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The v-safe after vaccination health checker: Active vaccine safety monitoring during CDC’s COVID-19 pandemic response
Abstract
The Centers for Disease Control and Prevention (CDC) developed and implemented the v-safe after vaccination health checker (v-safe) to monitor COVID-19 vaccine safety and as an active surveillance supplement to existing CDC vaccine safety monitoring programs. V-safe allows persons who received COVID-19 vaccines to report on post-vaccination experiences and how symptoms affected their health at daily, weekly, and monthly timepoints after vaccination. Text message reminders are sent linking to Internet-based health check-in surveys. Surveys include questions to identify v-safe participants who may be eligible to enroll in a separate pregnancy registry activity that evaluates maternal and infant outcomes in those pregnant at the time of vaccination or receiving vaccine in the periconception period. We describe the development of and enhancements to v-safe, data management, promotion and communication to vaccination sites and partners, publications, strengths and limitations, and implications for future systems. We also describe enrollment in v-safe over time and demographics of persons participating in v-safe during the first year of operation (December 14, 2020 - December 13, 2021). During this time, 9,342,582 persons submitted 131,543,087 v-safe surveys. The majority of participants were female (62.3 %) and non-Hispanic White (61.2 %); median age was 49.0 years. Most participants reported receiving an mRNA COVID-19 vaccine as their first recorded dose (95.0 %). V-safe contributed to CDC's vaccine safety assessments for FDA-authorized COVID-19 vaccines by enabling near real-time reporting of reactogenicity once the COVID-19 vaccination program began in the community, encouraging reports to the Vaccine Adverse Event Reporting System and facilitating enrollment in a large post-vaccination pregnancy registry. Given that v-safe is an integral component of the most comprehensive safety monitoring program in U.S. history, we believe that this approach has promise as a potential application for future pandemic response activities as well as rollout of novel vaccines in a non-pandemic context.
... VAERS, acting as an early warning system, can identify AEFIs requiring further investigation, which can be accomplished through active monitoring systems including V-Safe, VSD, the biologics effectiveness and safety system (BEST) and the center for Medicare and Medicaid services (CMS) [93]. V-safe is a smartphone based platform which prompts users to complete health surveys after vaccination. ...
... Surveys ask about injection site reactions, as well as systemic reactions such as muscle aches, chills or headaches. Participants may also record any other symptoms in a free text field [93]. ...
... During the COVID-19 pandemic, the large volumes of AE reports received by industry and regulators surpassed the projected numbers. Much was done (pre-and intrapandemic) to augment the reporting platforms (from mobile applications to digital AE reporting forms and digital self-reporting surveillance systems) [5][6][7]. These digital tools were critical in allowing timely reporting and further supplemented active surveillance of post-vaccination symptoms [5]. ...
... Much was done (pre-and intrapandemic) to augment the reporting platforms (from mobile applications to digital AE reporting forms and digital self-reporting surveillance systems) [5][6][7]. These digital tools were critical in allowing timely reporting and further supplemented active surveillance of post-vaccination symptoms [5]. Beyond these digital tools, there is an equal if not more important need to enhance the global data management capabilities and implement digital innovations that can further integrate reporting tools into healthcare systems, thereby allowing active surveillance through primary and secondary data analysis. ...
... To respond to the unprecedented COVID-19 pandemic and control its public health impact, the development, approval, and distribution of safe and effective vaccines were rapidly accelerated [1]. Consequently, each country has been establishing and implementing a monitoring system for the safety of COVID-19 vaccines [1][2][3]. In Korea, a web-based passive vaccine safety surveillance system and a text message-based active vaccine safety surveillance system have been implemented [4,5]. ...
... When interpreting the results of this study, in addition to the limitations reported in a previous study [3], the following points need to be kept in mind. Because similar responses were mixed, local, and systemic adverse reactions were not analyzed separately. ...
Background Unstructured text data collected through a surveillance system for vaccine safety monitoring can identify previously unreported adverse reactions and provide the information necessary to improve the surveillance system. Therefore, this study explored adverse reactions using text data gathered through an active surveillance system following monovalent XBB.1.5 COVID-19 vaccination. Methods A text mining analysis was conducted on 2,608 records from 1,864 individuals who reported any health conditions experienced within 7 days after vaccination in text format. Frequency analysis of key terms was performed, with subsequent analysis by sex, age, and concurrent influenza vaccination. Furthermore, semantic network analysis was conducted on terms reported simultaneously. Results The analysis identified various common (≥ 1%) adverse events, such as sleep disturbances, lumbago, and indigestion, which had not been frequently reported in prior literature. Moreover, although not common (≥ 0.1% to < 1%), adverse reactions affecting the eyes, ears, and oral cavity were also noted. These adverse reactions showed no significant differences in occurrence with or without simultaneous influenza vaccination. Through cooccurrence analysis and correlation coefficient assessments, associations were found between diarrhea and abdominal pain, as well as between musculoskeletal symptoms and cold-related symptoms. Conclusion This study used text mining to reveal previously unrecognized adverse reactions related to COVID-19 vaccination, thus expanding our understanding of the vaccine’s safety profile. The insights gained could further the scope of future investigations into adverse reactions to vaccines and improve the processing of text data in surveillance systems.
... From December 15, 2020, through June 21, 2021, women who reported a pregnancy to V-safe internet-based health check-in surveys (Myers et al. 2023) were screened for eligibility in the CDC COVID-19 Vaccine Pregnancy Registry (C19VPR), which was developed to monitor the safety of COVID-19 vaccines in pregnancy at the beginning of the implementation of the US COVID-19 vaccination program (Gee et al. 2024). At the time of C19VPR eligibility, only first-generation monovalent index virus vaccines were available (i.e., two-dose Moderna and Pfizer-BioNTech mRNA vaccines and the one-dose Janssen adenoviral-vector vaccine) (Centers for Disease Control and Prevention 2023). ...
Background
We calculated prevalences of birth defects among infants of participants in the Centers for Disease Control and Prevention's (CDC) COVID‐19 Vaccine Pregnancy Registry (C19VPR).
Methods
C19VPR enrolled women receiving COVID‐19 vaccines ≤ 30 days before the last menstrual period or during pregnancy from December 2020 through June 2021. We included 19,931 participants with singleton pregnancies ending ≥ 20 weeks' gestation who did not report COVID‐19 illness during pregnancy. Clinicians identified birth defects from participant‐reported infant health information up to 4 months after birth. We compared C19VPR birth defect prevalences to published pre‐pandemic estimates. For seven defects originating during embryogenesis (cleft lip with/without cleft palate, atrial septal defect, coarctation of the aorta, ventricular septal defect, esophageal atresia or stenosis, hypospadias, kidney agenesis/hypoplasia/dysplasia), we estimated prevalence ratios comparing those vaccinated < 14 weeks' to those vaccinated ≥ 14 weeks' gestation.
Results
Participants reported receiving Pfizer‐BioNTech vaccines (59.0%), Moderna (38.2%), and Janssen (2.8%) vaccines. Most (65.2%) participants received their first COVID‐19 vaccine after the first trimester. The prevalence of major birth defects was 3.8%. Among defects with comparator estimates available ( n = 50), 35 were below or within expected ranges. C19VPR prevalences were higher than the comparator confidence interval for 15 defects; however, C19VPR confidence intervals included comparator estimates. Prevalences did not differ by the timing of vaccination for seven defects examined.
Conclusions
Birth defects prevalence estimates among infants born to women receiving COVID‐19 vaccines during or just prior to pregnancy were generally similar to pre‐pandemic estimates. While there was no strong evidence of associations between vaccination and specific defects, statistical power was low.
... This comprehensive approach included clinical consultations, long-term follow-up on individual cases of myocarditis after immunization, both active and passive surveillance, and monitoring of pregnancy and infant outcomes. The most efficient methods for disseminating the latest information to stakeholders and the public involved updating agency websites, engaging through social media, presenting findings to federal advisory bodies, and publishing safety results in scientific journals (48,49). ...
Vaccination is considered to be one of the most effective means of protecting individuals and populations from the risks associated with exposure to various pathogens. The COVID-19 pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), affected people of all ages worldwide. In response, several pharmaceutical companies rapidly leveraged their resources to develop vaccines within a very short period of time, leading to the introduction of new, improved, and combination vaccines for community-wide immunization. This review aims to provide a summary of the available literature on the efficacy and safety of COVID-19 vaccines in the pediatric population ranging from 0 to 18 years. An analysis of recent published studies reveals that the majority of clinical trials have reported a sustained immune response following COVID-19 vaccination in children across various age groups worldwide. The majority of the authors highlighted the effectiveness and safety of immunization schedules in children and adolescents. The population-level efficacy of this vaccination remains to be determined, provided that the benefits outweigh the potential risks. Long-term side effects must still be monitored to enable the development of safer and more effective vaccines for future pandemics.
... Esta estrategia de vigilancia centinela permite detectar señales de alerta al comparar la frecuencia de eventos esperados y de eventos observados (4). Si bien existen publicaciones que muestran datos de líneas de base (8) y experiencias con otras modalidades de vigilancia activa (9,10) no se dispone de estudios a nivel nacional que utilicen la metodología de las unidades centinelas para la vigilancia de ESAVI y EVADIE posterior a la vacunación contra la COVID-19. ...
RESUMEN
Objetivo
Analizar los resultados de la vigilancia de eventos adversos de interés especial (EVADIE) en contexto de la campaña de vacunación contra la COVID-19 en una unidad centinela (UC) de Argentina; se comparó el período retrospectivo (prevacunación) con el prospectivo (vacunal) para identificar señales de alerta.
Método
Búsqueda de EVADIE en forma retrospectiva y prospectiva a partir de los códigos CIE-10 de egreso hospitalario. Se realizó un análisis descriptivo, suavizamiento de la tendencia por media móvil y cartas de control para detección de cambios en el comportamiento de EVADIE.
Resultados
Se identificaron 1 586 EVADIE. El análisis de la proporción según egresos reveló un aumento durante el período pandémico (2020) con descenso progresivo en el período de vacunación (2021-2022), a expensas de síndrome de dificultad respiratoria aguda (SDRA). Se comparó el suavizamiento por media móvil y cartas de control, y se destacaron momentos en los que la proporción de EVADIE superó los límites de control superior. En el período vacunal esto ocurrió para SDRA, trombosis, miocarditis, meningoencefalitis, síndrome inflamatorio multisistémico y anafilaxia. No se observaron diferencias para síndrome de Guillain-Barré, trombocitopenia ni pericarditis. Los eventos de encefalomielitis diseminada aguda, meningoencefalitis y pericarditis en el período vacunal no tenían antecedente de vacunación.
Conclusión
La vigilancia activa en la UC permitió identificar los EVADIE que presentaron mayor frecuencia en el período vacunal en comparación con la línea de base prevacunal, como así también se observó el efecto protector de la vacuna contra la COVID -19, en especial en la disminución de los casos del SDRA en el período posvacunal. Esta estrategia es útil para evaluar la seguridad de las vacunas identificando señales de alerta.
... Serious AEs included death; suspected anaphylaxis; AESIs such as myocarditis, pericarditis, or thrombocytopenia syndrome (TTS); intensive care unit (ICU) admission; life-threatening events; permanent disability or sequelae; and others. Another method of data collection for AEs was a text messaging-based survey, benchmarked from the v-safe after vaccination health checker in the US [18]. ...
Objectives:
This study analyzed the safety of coronavirus disease 2019 (COVID-19) bivalent and monovalent booster vaccines, including the frequency of adverse events (AEs) such as myocarditis and pericarditis, in adolescents aged 12 to 17 years in the Republic of Korea. We aimed to share the safety profile of the COVID-19 bivalent vaccine booster doses.
Methods:
We analyzed the frequencies of AEs reported to the COVID-19 vaccination management system (CVMS) or self-reported through the text message survey (TMS). Diagnostic eligibility and causality with vaccines were compared using odds ratios (ORs) by vaccine type, and incidence rates per 100,000 person-days were calculated for confirmed cases of myocarditis and pericarditis following monovalent and bivalent booster doses.
Results:
In the CVMS, the AE reporting rate (per 100,000 doses) was lower after the bivalent booster (66.5) than after the monovalent booster (264.6). Among the AEs reported for both monovalent and bivalent vaccines, 98.2% were non-serious and 1.8% were serious. According to the TMS, both local and systemic AEs were reported less frequently after the bivalent vaccination than after the monovalent vaccination in adolescents aged 12 to 17 years (p<0.001). The incidence rates per 100,000 person-days for confirmed myocarditis/pericarditis following monovalent and bivalent booster doses were 0.03 and 0.05, respectively; this difference was not statistically significant (OR, 1.797; 95% confidence interval, 0.210-15.386).
Conclusion:
AEs in 12- to 17-year-olds following the bivalent booster were less frequent than those following the monovalent booster in the Republic of Korea, and no major safety issues were identified. However, the reporting rates for AEs were low.
... V-safe is a voluntary smartphone-based vaccine safety surveillance system established by CDC in December 2020 to collect data on reactions and health impacts for registrants reporting COVID-19 vaccination. 5 through November 21, 2021. On November 22, 2021, V-safe began prospectively collecting the type of vaccine administered during the same visit. ...
Introduction COVID-19 vaccines may be administered with other vaccines during the same healthcare visit. COVID-19 monovalent (Fall 2021) and bivalent (Fall 2022) vaccine recommendations coincided with annual seasonal influenza vaccination. Data describing the frequency of the co-administration of COVID-19 vaccines with other vaccines are limited. Methods We used V-safe, a voluntary smartphone-based U.S. safety surveillance system established by the CDC, to describe trends in the administration of COVID-19 vaccines with other vaccines reported to V-safe during December 14, 2020 – May 19, 2023. Results Of the 21 million COVID-19 vaccinations reported to V-safe, 2.2% (459,817) were administered with at least 1 other vaccine. Co-administration most frequently occurred during the first week of October 2023 (27,092; 44.1%). Most reports of co-administration included influenza vaccine (393,003; 85.5%). Co-administration was most frequently reported for registrants aged 6 months-6 years (4,872; 4.4%). Conclusion Reports of co-administration to V-safe peaked during October 2023, when influenza vaccination most often occurs, possibly reflecting increased opportunities for multiple vaccinations and greater acceptability of the co-administration of COVID-19 vaccine with other vaccines, especially influenza vaccine.
... Rates of engagement (19.1%) for those receiving TM may seem low compared with other text-based public health programs, such as the Centers for Disease Control and Prevention v-safe vaccine safety monitoring program, which uses an opt-in model of recruitment (ie, potential participants chose to enroll), likely resulting in a more motivated study sample. 25 In contrast, SCALE-UP Counts used an optout model of recruitment where participants were automatically enrolled unless they actively chose to opt out of participating. Thus, participants may not have felt it necessary to respond to messages, particularly when they had no COVID-19 symptoms or exposure. ...
Objectives:
SCALE-UP Counts tests population health management interventions to promote coronavirus disease 2019 (COVID-19) testing in kindergarten through 12th-grade schools that serve populations that have been historically marginalized.
Methods:
Within 6 participating schools, we identified 3506 unique parents/guardians who served as the primary contact for at least 1 student. Participants were randomized to text messaging (TM), text messaging + health navigation (HN) (TM + HN), or usual care. Bidirectional texts provided COVID-19 symptom screening, along with guidance on obtaining and using tests as appropriate. If parents/guardians in the TM + HN group were advised to test their child but either did not test or did not respond to texts, they were called by a trained health navigator to address barriers.
Results:
Participating schools served a student population that was 32.9% non-white and 15.4% Hispanic, with 49.6% of students eligible to receive free lunches. Overall, 98.8% of parents/guardians had a valid cell phone, of which 3.8% opted out. Among the 2323 parents/guardians included in the intervention, 79.6% (n = 1849) were randomized to receive TM, and 19.1% (n = 354) engaged with TM (ie, responded to at least 1 message). Within the TM + HN group (40.1%, n = 932), 1.3% (n = 12) qualified for HN at least once, of which 41.7% (n = 5) talked to a health navigator.
Conclusions:
TM and HN are feasible ways to reach parents/guardians of kindergarten through 12th-grade students to provide COVID-19 screening messages. Strategies to improve engagement may strengthen the impact of the intervention.
Purpose
Reports of Raynaud's phenomenon following vaccination have been steadily increasing; however, research on vaccine-associated Raynaud's phenomenon remains limited. This study aims to provide a comprehensive analysis of the association between Raynaud's phenomenon and various vaccines.
Method
This study used data from international pharmacovigilance, which contains over 35 million adverse event cases from more than 140 countries. Two established pharmacovigilance indicators, the information component (IC) and reporting odds ratio (ROR), were employed in the analysis with 95% confidence interval (CI). The IC was derived using a Bayesian methodology to compare the reporting and non-reporting groups, while the ROR, a frequentist measure of association, was calculated using contingency tables based on the number of adverse events.
Results
The signal with Raynaud's phenomenon was highest for papillomavirus vaccines (ROR: 11.49 [95% CI, 9.66–13.67]; IC: 3.45 [IC0.25, 3.16]), followed in order by typhoid (5.86 [2.93–11.72]), hepatitis B (5.63 [4.25–7.45]; 2.42 [1.95]), COVID-19 mRNA (5.00 [4.70–5.31]; 2.00 [1.91]), and hepatitis A vaccines (4.35 [2.87–6.62]; 2.02 [1.30]). The signal was higher in females (ROR: 3.74 [95% CI, 3.54–3.95]; IC: 1.67 [IC0.25, 1.59]) compared to males (3.44 [3.12–3.78]; 1.57 [1.43]), and it increased monotonically with age (0–11 years: IC [IC0.25] 0.03 [-0.56]; 12–17 years: 1.54 [1.25]; 18–44 years: 1.64 [1.52]; 45–64 years: 2.00 [1.87]; ≥ 65 years: 2.12 [1.91]).
Conclusion
This study suggests the potential signal association between various vaccines and Raynaud's phenomenon. Although our study does not imply causality, we propose the need to strengthen post-vaccination monitoring and establish support policies to address such adverse events.
Introduction: SARS-CoV-2 (COVID-19) infection has been implicated in the onset of neuropsychiatric symptoms in adults and children. While outcomes of COVID-19 infection and vaccination have been tracked in the general pediatric population, little is known of their impact on children with preexisting neuropsychiatric syndromes, including pediatric acute-onset neuropsychiatric syndrome (PANS) and pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS). The aim of this study is to understand the prevalence and severity of COVID-19 symptoms and PANS/PANDAS symptoms following COVID-19 infection or vaccination in children with PANS/PANDAS. Methods: We analyzed retrospective COVID-19 survey data from caregivers of youth with PANS/PANDAS at Massachusetts General Hospital (MGH; n = 57) and the International PANS Registry (IPR; n = 478). Surveys were conducted online between late 2021 and early 2022 to collect COVID-19 infection and vaccination histories, side effects, and changes in PANS/PANDAS symptoms. Descriptive results are reported, stratified by case and sibling groups within the IPR sample. Results: Among patients with test-confirmed COVID-19 (MGH: n = 20, IPR: n = 65 cases, n = 16 siblings), mild/minor COVID-19 symptoms were common (62-75%). All patients with preexisting PANS/PANDAS-related symptoms at the time of COVID-19 infection experienced an exacerbation of PANS/PANDAS symptoms, while remitted patients did not report any PANS/PANDAS symptoms. Following the first COVID-19 vaccine dose (MGH: n = 45, IPR: n = 150 cases, n = 44 siblings), fatigue was the predominant side effect (30-56%). Most patients did not report new (59-81%) or worsened (71-82%) PANS symptoms post-vaccination, irrespective of symptomatic status at vaccination. Vaccine hesitancy often stemmed from concerns that the vaccination would cause an exacerbation of PANS/PANDAS symptoms. Conclusions: In two samples of children with PANS/PANDAS, symptoms of COVID-19 following infection and vaccination were common and generally mild to moderate. Children experiencing PANS/PANDAS symptoms at the time of COVID-19 infection experienced an increase in PANS/PANDAS symptom severity.
Introduction: In 2021, the European Medicines Agency supported the “Covid Vaccine Monitor (CVM),” an active surveillance project spanning 13 European countries aimed at monitoring the safety of COVID-19 vaccines in general and special populations (i.e., pregnant/breastfeeding women, children/adolescents, immunocompromised people, and people with a history of allergies or previous SARS-CoV-2 infection). Italy participated in this project as a large multidisciplinary network called the “ilmiovaccinoCOVID19 collaborating group.”
Methods: The study aimed to describe the experience of the Italian network “ilmiovaccinoCOVID19 collaborating group” in the CVM context from June 2021 to February 2023. Comprising about 30 partners, the network aimed to facilitate vaccinee recruitment. Participants completed baseline and follow-up questionnaires within 48 h from vaccination over a 6-month period. Analyses focused on those who completed both the baseline and the first follow-up questionnaire (Q1), exploring temporal trends, vaccination campaign correlation, and loss to follow-up. Characteristics of recruited vaccinees and vaccinee-reported adverse drug reactions (ADRs) were compared with passive surveillance data in Italy.
Results: From June 2021 to November 2022, 22,384,663 first doses and 38,207,452 booster doses of COVID-19 vaccines were administered in Italy. Simultaneously, the study enrolled 1,229 and 2,707 participants for the first and booster doses, respectively. Of these, 829 and 1,879 vaccinees, respectively, completed both baseline and at least Q1 and were included in the analyses, with a significant proportion of them (57.8%/34.3%) belonging to special cohorts. Most vaccinees included in the analyses were women. Comirnaty ® (69%) and Spikevax ® (29%) were the most frequently administered vaccines. ADR rates following Comirnaty ® and Spikevax ® were higher after the second dose, particularly following Spikevax ® . Serious ADRs were infrequent. Differences were observed in ADR characteristics between CVM and Italian passive surveillance.
Conclusion: This study confirmed the favorable safety profile of COVID-19 vaccines, with findings consistent with pivotal clinical trials of COVID-19 vaccines, although different proportions of serious ADRs compared to spontaneous reporting were observed. Continuous evaluation through cohort event monitoring studies provides real-time insights crucial for regulatory responses. Strengthening infrastructure and implementing early monitoring strategies are essential to enhance vaccine safety assessment and prepare for future pandemics.
Background
In response to the 2022 mpox outbreak in the United States, people with higher potential for exposure to mpox were recommended to receive two doses of the JYNNEOS vaccine. Vaccine safety was monitored using two complementary systems.
Methods
The Vaccine Adverse Event Reporting System (VAERS) is a passive surveillance system that accepts reports of adverse events following vaccination. VAERS is capable of rapidly identifying rare adverse events and unusual reporting patterns. Medical records were requested and reviewed for adverse events of special interest, including myocarditis. Adverse event reporting rates were calculated as the number of verified adverse event cases divided by the number of JYNNEOS doses administered. V-safe for mpox was a voluntary smartphone-based vaccine safety surveillance system that sent enrolled persons text messages linked to health surveys asking about reactions and health impact events occurring after vaccination.
Results
There were 1,207,056 JYNNEOS doses administered in the United States. VAERS received 1,927 reports for JYNNEOS. The myocarditis reporting rate per million doses was 2.69 after dose 1 and 8.64 after dose 2. V-safe had 213 participants complete at least one health survey. Rates of injection site and systemic reactions were similar in the first week following dose 1 and dose 2.
Conclusions
JYNNEOS vaccine safety surveillance findings from VAERS and v-safe did not identify any unexpected safety concerns. The VAERS reporting rate for myocarditis was similar to previously published population background rates.
Background:
On 2/27/2021, FDA authorized Janssen COVID-19 Vaccine (Ad.26.COV2.S) for use in individuals 18 years of age and older. Vaccine safety was monitored using the Vaccine Adverse Event Reporting System (VAERS), a national passive surveillance system, and v-safe, a smartphone-based surveillance system.
Methods:
VAERS and v-safe data from 2/27/2021 to 2/28/2022 were analyzed. Descriptive analyses included sex, age, race/ethnicity, seriousness, AEs of special interest (AESIs), and cause of death. For prespecified AESIs, reporting rates were calculated using the total number of doses of Ad26.COV2.S administered. For myopericarditis, observed-to-expected (O/E) analysis was performed based on the number verified cases, vaccine administration data, and published background rates. Proportions of v-safe participants reporting local and systemic reactions, as well as health impacts, were calculated.
Results:
During the analytic period, 17,018,042 doses of Ad26.COV2.S were administered in the United States, and VAERS received 67,995 reports of AEs after Ad26.COV2.S vaccination. Most AEs (59,750; 87.9 %) were non-serious and were similar to those observed during clinical trials. Serious AEs included COVID-19 disease, coagulopathy (including thrombosis with thrombocytopenia syndrome; TTS), myocardial infarction, Bell's Palsy, and Guillain-Barré syndrome (GBS). Among AESIs, reporting rates per million doses of Ad26.COV2.S administered ranged from 0.06 for multisystem inflammatory syndrome in children to 263.43 for COVID-19 disease. O/E analysis revealed elevated reporting rate ratios (RRs) for myopericarditis; among adults ages 18-64 years, the RR was 3.19 (95 % CI 2.00, 4.83) within 7 days and 1.79 (95 % CI 1.26, 2.46) within 21 days of vaccination. Of 416,384 Ad26.COV2.S recipients enrolled into v-safe, 60.9 % reported local symptoms (e.g. injection site pain) and 75.9 % reported systemic symptoms (e.g., fatigue, headache). One-third of participants (141,334; 33.9 %) reported a health impact, but only 1.4 % sought medical care.
Conclusion:
Our review confirmed previously established safety risks for TTS and GBS and identified a potential safety concern for myocarditis.
As of February 20, 2022, only BNT162b2 (Pfizer-BioNTech) COVID-19 vaccine has been authorized for use in persons aged 12-17 years in the United States (1). The Food and Drug Administration (FDA) amended the Emergency Use Authorization (EUA) for Pfizer-BioNTech vaccine on December 9, 2021, to authorize a homologous* booster dose for persons aged 16-17 years ≥6 months after receipt of dose 2 (1). On January 3, 2022, authorization was expanded to include persons aged 12-15 years, and for all persons aged ≥12 years, the interval between dose 2 and booster dose was shortened to ≥5 months (1). To characterize the safety of Pfizer-BioNTech booster doses among persons aged 12-17 years (adolescents), CDC reviewed adverse events and health impact assessments during the week after receipt of a homologous Pfizer-BioNTech booster dose reported to v-safe, a voluntary smartphone-based safety surveillance system for adverse events after COVID-19 vaccination, and adverse events reported to the Vaccine Adverse Event Reporting System (VAERS), a passive vaccine safety surveillance system managed by CDC and FDA. During December 9, 2021-February 20, 2022, approximately 2.8 million U.S. adolescents received a Pfizer-BioNTech booster dose.† During this period, receipt of 3,418 Pfizer-BioNTech booster doses were reported to v-safe for adolescents. Reactions were reported to v-safe with equal or slightly higher frequency after receipt of a booster dose than after dose 2, were primarily mild to moderate in severity, and were most frequently reported the day after vaccination. VAERS received 914 reports of adverse events after Pfizer-BioNTech booster dose vaccination of adolescents; 837 (91.6%) were nonserious and 77 (8.4%) were serious. Health care providers, parents, and adolescents should be advised that local and systemic reactions are expected among adolescents after homologous Pfizer-BioNTech booster vaccination, and that serious adverse events are rare.
During September 22, 2021-February 6, 2022, approximately 82.6 million U.S. residents aged ≥18 years received a COVID-19 vaccine booster dose.* The Food and Drug Administration (FDA) has authorized a booster dose of either the same product administered for the primary series (homologous) or a booster dose that differs from the product administered for the primary series (heterologous). These booster authorizations apply to all three COVID-19 vaccines used in the United States (1-3).† The Advisory Committee on Immunization Practices (ACIP) recommended preferential use of an mRNA COVID-19 vaccine (mRNA-1273 [Moderna] or BNT162b2 [Pfizer-BioNTech]) for a booster, even for persons who received the Ad26.COV2.S (Janssen [Johnson & Johnson]) COVID-19 vaccine for their single-dose primary series.§ To characterize the safety of COVID-19 vaccine boosters among persons aged ≥18 years during September 22, 2021-February 6, 2022, CDC reviewed adverse events and health impact assessments following receipt of a booster that were reported to v-safe, a voluntary smartphone-based safety surveillance system for adverse events after COVID-19 vaccination, and adverse events reported to the Vaccine Adverse Event Reporting System (VAERS), a passive vaccine safety surveillance system managed by CDC and FDA. Among 721,562 v-safe registrants aged ≥18 years who reported receiving a booster, 88.8% received homologous COVID-19 mRNA vaccination. Among registrants who reported a homologous COVID-19 mRNA booster dose, systemic reactions were less frequent following the booster (58.4% [Pfizer-BioNTech] and 64.4% [Moderna], respectively) than were those following dose 2 (66.7% and 78.4%, respectively). The adjusted odds of reporting a systemic reaction were higher following a Moderna COVID-19 vaccine booster, irrespective of the vaccine received for the primary series. VAERS has received 39,286 reports of adverse events after a COVID-19 mRNA booster vaccination for adults aged ≥18 years, including 36,282 (92.4%) nonserious and 3,004 (7.6%) serious events. Vaccination providers should educate patients that local and systemic reactions are expected following a homologous COVID-19 mRNA vaccine booster; however, these reactions appear less common than those following dose 2 of an mRNA-based vaccine. CDC and FDA will continue to monitor vaccine safety and provide data to guide vaccine recommendations and protect public health.
On October 29, 2021, the Food and Drug Administration (FDA) amended the Emergency Use Authorization (EUA) for Pfizer-BioNTech COVID-19 (BNT162b2) mRNA vaccine to expand its use to children aged 5-11 years, administered as 2 doses (10 μg, 0.2mL each) 3 weeks apart (1). As of December 19, 2021, only the Pfizer-BioNTech COVID-19 vaccine is authorized for administration to children aged 5-17 years (2,3). In preauthorization clinical trials, Pfizer-BioNTech COVID-19 vaccine was administered to 3,109 children aged 5-11 years; most adverse events were mild to moderate, and no serious adverse events related to vaccination were reported (4). To further characterize safety of the vaccine in children aged 5-11 years, CDC reviewed adverse events after receipt of Pfizer-BioNTech COVID-19 vaccine reported to the Vaccine Adverse Event Reporting System (VAERS), a passive vaccine safety surveillance system co-managed by CDC and FDA, and adverse events and health impact assessments reported to v-safe, a voluntary smartphone-based safety surveillance system for adverse events after COVID-19 vaccination,* during November 3-December 19, 2021. Approximately 8.7 million doses of Pfizer-BioNTech COVID-19 vaccine were administered to children aged 5-11 years† during this period; VAERS received 4,249 reports of adverse events after vaccination with Pfizer-BioNTech COVID-19 vaccine in this age group, 4,149 (97.6%) of which were not serious. Approximately 42,504 children aged 5-11 years were enrolled in v-safe after vaccination with Pfizer-BioNTech COVID-19 vaccine; after dose 2, a total of 17,180 (57.5%) local and 12,223 systemic (40.9%) reactions (including injection-site pain, fatigue, or headache) were reported. The preliminary safety findings are similar to those from preauthorization clinical trials (4,5). The Advisory Committee on Immunization Practices (ACIP) recommends the Pfizer-BioNTech COVID-19 vaccine for children aged 5-11 years for the prevention of COVID-19 (6). Parents and guardians of children aged 5-11 years vaccinated with Pfizer-BioNTech COVID-19 vaccine should be advised that local and systemic reactions are expected after vaccination. Vaccination is the most effective way to prevent COVID-19. CDC and FDA will continue to monitor vaccine safety and will provide updates as needed to guide COVID-19 vaccination recommendations.
( New Engl J Med . 2021;384:2273–2282)
When the Moderna and Pfizer-BioNTech COVID-19 vaccines were granted Emergency Use Authorization by the Food and Drug Administration in December 2020, there was limited data concerning the safety of these vaccines during pregnancy. Pregnant individuals with COVID-19 are at higher risk for severe illness, death and adverse pregnancy outcomes. The Centers for Disease Control and Prevention (CDC) and other organizations have indicated that pregnant people can receive the COVID-19 vaccines. Monitoring pregnant individuals who have received the COVID-19 vaccines, and establishing safety profiles is important to inform future recommendations. This study reports on preliminary data on COVID-19 vaccine safety in pregnant patients.
On August 12, 2021, the Food and Drug Administration (FDA) amended Emergency Use Authorizations (EUAs) for the Pfizer-BioNTech and Moderna COVID-19 vaccines to authorize administration of an additional dose after completion of a primary vaccination series to eligible persons with moderate to severe immunocompromising conditions (1,2). On September 22, 2021, FDA authorized an additional dose of Pfizer-BioNTech vaccine ≥6 months after completion of the primary series among persons aged ≥65 years, at high risk for severe COVID-19, or whose occupational or institutional exposure puts them at high risk for COVID-19 (1). Results from a phase 3 clinical trial conducted by Pfizer-BioNTech that included 306 persons aged 18-55 years showed that adverse reactions after receipt of a third dose administered 5-8 months after completion of a 2-dose primary mRNA vaccination series were similar to those reported after receipt of dose 2; these adverse reactions included mild to moderate injection site and systemic reactions (3). CDC developed v-safe, a voluntary, smartphone-based safety surveillance system, to provide information on adverse reactions after COVID-19 vaccination. Coincident with authorization of an additional dose for persons with immunocompromising conditions, the v-safe platform was updated to allow registrants to enter information about additional doses of COVID-19 vaccine received. During August 12-September 19, 2021, a total of 22,191 v-safe registrants reported receipt of an additional dose of COVID-19 vaccine. Most (97.6%) reported a primary 2-dose mRNA vaccination series followed by a third dose of the same vaccine. Among those who completed a health check-in survey for all 3 doses (12,591; 58.1%), 79.4% and 74.1% reported local or systemic reactions, respectively, after dose 3, compared with 77.6% and 76.5% who reported local or systemic reactions, respectively, after dose 2. These initial findings indicate no unexpected patterns of adverse reactions after an additional dose of COVID-19 vaccine; most of these adverse reactions were mild or moderate. CDC will continue to monitor vaccine safety, including the safety of additional doses of COVID-19 vaccine, and provide data to guide vaccine recommendations and protect public health.
The Emergency Use Authorization (EUA) originated in 2004 because of the need for emergency medical countermeasures (MCMs) against potential bioterrorist attacks. The EUA also proved useful in dealing with subsequent pandemics and has emerged as a critical regulatory pathway for therapeutics and vaccines throughout the Coronavirus Disease 2019 (COVID-19) pandemic. With the EUA process in the USA, we witnessed emergency authorizations, their expansions, as well as withdrawal of previously authorized products, which exemplifies the dynamic nature of scientific review of EUA products. EUAs proved vital for the first group of COVID-19 vaccines, including the temporary pause of one vaccine while emergency safety issues were evaluated. Although this review on the EUA is primarily focused on the USA, distinctions were made with other jurisdictions such as Europe and Canada with respect to the emergency authorizations of the vaccines. Finally, we discuss some important differences following EUA and formal new drug/vaccine application (NDA/BLA) approvals.
What is already known about this topic? In preauthorization trials of the Pfizer-BioNTech COVID-19 vaccine, adolescents aged 12-17 years reported local and systemic mild and moderate reactions. Myocarditis has been observed after vaccination with mRNA vaccines in postauthorization monitoring. What is added by this report? Local and systemic reactions after vaccination with Pfizer-BioNTech vaccine were commonly reported by adolescents aged 12-17 years to U.S. vaccine safety monitoring systems, especially after dose 2. A small proportion of these reactions are consistent with myocarditis. What are the implications for public health practice? Mild local and systemic reactions are common among adolescents following Pfizer-BioNTech vaccine, and serious adverse events are rare. The Advisory Committee on Immunization Practices conducted a risk-benefit assessment and continues to recommend the Pfizer-BioNTech COVID-19 vaccine for all persons aged ≥12 years. © 2021 Department of Health and Human Services. All rights reserved.
On February 27, 2021, the Food and Drug Administration (FDA) issued an Emergency Use Authorization (EUA) for Janssen (Ad.26.COV2.S) COVID-19 vaccine (Janssen Biotech, Inc., a Janssen Pharmaceutical company, Johnson & Johnson) (1). The Janssen COVID-19 vaccine, the third COVID-19 vaccine authorized for use in the United States, uses a replication-incompetent human adenoviral type 26 vector platform* (2) and is administered as a single intramuscular dose, whereas the first two authorized vaccines use an mRNA platform and require 2 doses. On February 28, 2021, the Advisory Committee on Immunization Practices (ACIP) issued interim recommendations for use of Janssen COVID-19 vaccine among persons aged ≥18 years (3). During April 13-23, CDC and FDA recommended a pause in use of Janssen vaccine after reports of six cases of cerebral venous sinus thrombosis (CVST) with thrombocytopenia (platelet count <150,000/μL of blood) among Janssen vaccine recipients (4). Similar thrombotic events, primarily among women aged <60 years, have been described in Europe after receipt of the AstraZeneca COVID-19 vaccine, which uses a replication-incompetent chimpanzee adenoviral vector (5-7). The U.S. CVST cases that prompted the pause in Janssen vaccination, as well as subsequently detected CVST cases, are described elsewhere (8). This report summarizes adverse events among Janssen vaccine recipients, including non-CVST cases of thrombosis with thrombocytopenia syndrome (TTS), reported to the Vaccine Adverse Events Reporting System (VAERS), a passive surveillance system, and through v-safe, an active monitoring system. As of April 21, 2021, 7.98 million doses of the Janssen COVID-19 vaccine had been administered. Among 13,725 VAERS reports reviewed, 97% were classified as nonserious and 3% as serious,† including three reports among women of cases of thrombosis in large arteries or veins accompanied by thrombocytopenia during the second week after vaccination. These three cases and the previously detected CVST cases are consistent with 17 cases of TTS,§ a newly defined condition. Approximately 338,700 Janssen COVID-19 vaccine recipients completed at least one v-safe survey during the week after vaccination; 76% reported a systemic reaction, 61% reported a local reaction, and 34% reported a health impact.¶ Fatigue and pain were commonly reported symptoms in both VAERS and v-safe. The overall safety profile is consistent with preauthorization clinical trials data. Prompt review of U.S. vaccine safety data detected three additional cases of non-CVST TTS, in addition to the previously recognized CVST cases that initiated the pause in use of the Janssen COVID-19 vaccine. Ongoing monitoring of adverse events after COVID-19 vaccination, including vaccination with the Janssen single-dose vaccine, is essential for evaluating the risks and benefits of each vaccine.
Background
Many pregnant persons in the United States are receiving messenger RNA (mRNA) coronavirus disease 2019 (Covid-19) vaccines, but data are limited on their safety in pregnancy.
Methods
From December 14, 2020, to February 28, 2021, we used data from the “v-safe after vaccination health checker” surveillance system, the v-safe pregnancy registry, and the Vaccine Adverse Event Reporting System (VAERS) to characterize the initial safety of mRNA Covid-19 vaccines in pregnant persons.
Results
A total of 35,691 v-safe participants 16 to 54 years of age identified as pregnant. Injection-site pain was reported more frequently among pregnant persons than among nonpregnant women, whereas headache, myalgia, chills, and fever were reported less frequently. Among 3958 participants enrolled in the v-safe pregnancy registry, 827 had a completed pregnancy, of which 115 (13.9%) resulted in a pregnancy loss and 712 (86.1%) resulted in a live birth (mostly among participants with vaccination in the third trimester). Adverse neonatal outcomes included preterm birth (in 9.4%) and small size for gestational age (in 3.2%); no neonatal deaths were reported. Although not directly comparable, calculated proportions of adverse pregnancy and neonatal outcomes in persons vaccinated against Covid-19 who had a completed pregnancy were similar to incidences reported in studies involving pregnant women that were conducted before the Covid-19 pandemic. Among 221 pregnancy-related adverse events reported to the VAERS, the most frequently reported event was spontaneous abortion (46 cases).
Conclusions
Preliminary findings did not show obvious safety signals among pregnant persons who received mRNA Covid-19 vaccines. However, more longitudinal follow-up, including follow-up of large numbers of women vaccinated earlier in pregnancy, is necessary to inform maternal, pregnancy, and infant outcomes.
Two coronavirus disease 2019 (COVID-19) vaccines are currently authorized for use in the United States. The Food and Drug Administration (FDA) issued Emergency Use Authorization (EUA) for the Pfizer-BioNTech COVID-19 vaccine on December 11, 2020, and for the Moderna COVID-19 vaccine on December 18, 2020; each is administered as a 2-dose series. The Advisory Committee on Immunization Practices issued interim recommendations for Pfizer-BioNTech and Moderna COVID-19 vaccines on December 12, 2020 (1), and December 19, 2020 (2), respectively; initial doses were recommended for health care personnel and long-term care facility (LTCF) residents (3). Safety monitoring for these vaccines has been the most intense and comprehensive in U.S. history, using the Vaccine Adverse Event Reporting System (VAERS), a spontaneous reporting system, and v-safe,* an active surveillance system, during the initial implementation phases of the COVID-19 national vaccination program (4). CDC conducted descriptive analyses of safety data from the first month of vaccination (December 14, 2020-January 13, 2021). During this period, 13,794,904 vaccine doses were administered, and VAERS received and processed† 6,994 reports of adverse events after vaccination, including 6,354 (90.8%) that were classified as nonserious and 640 (9.2%) as serious.§ The symptoms most frequently reported to VAERS were headache (22.4%), fatigue (16.5%), and dizziness (16.5%). A total of 113 deaths were reported to VAERS, including 78 (65%) among LTCF residents; available information from death certificates, autopsy reports, medical records, and clinical descriptions from VAERS reports and health care providers did not suggest any causal relationship between COVID-19 vaccination and death. Rare cases of anaphylaxis after receipt of both vaccines were reported (4.5 reported cases per million doses administered). Among persons who received Pfizer-BioNTech vaccine, reactions reported to the v-safe system were more frequent after receipt of the second dose than after the first. The initial postauthorization safety profiles of the two COVID-19 vaccines in current use did not indicate evidence of unexpected serious adverse events. These data provide reassurance and helpful information regarding what health care providers and vaccine recipients might expect after vaccination.
Background
Risk of experiencing a systemic adverse event (AE) after mRNA coronavirus disease 2019 (COVID-19) vaccination may be greater among persons with a history of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection; data on serious events are limited. We assessed if adults reporting systemic AEs resulting in emergency department visits or hospitalizations during days 0–7 after mRNA COVID-19 vaccine dose 1 were more likely to have a history of prior SARS-CoV-2 infection compared with persons who reported no or non-severe systemic AEs.
Methods
We conducted a nested case-control study using v-safe surveillance data. Participants were ≥18 years and received dose 1 during December 14, 2020─May 9, 2021. Cases reported severe systemic AEs 0–7 days after vaccination. Three controls were frequency matched per case by age, vaccination date, and days since vaccination. Follow-up surveys collected SARS-CoV-2 histories.
Results
Follow-up survey response rates were 38.6% (potential cases) and 56.8% (potential controls). In multivariable analyses including 3,862 case-patients and 11,586 controls, the odds of experiencing a severe systemic AE were 2.4 (Moderna, mRNA-1273; 95% confidence interval [CI]: 1.89, 3.09) and 1.5 (Pfizer-BioNTech, BNT162b2; 95% CI: 1.17, 2.02) times higher among participants with pre-vaccination SARS-CoV-2 histories compared with those without. Medical attention of any kind for symptoms during days 0–7 following dose 2 was not common among case-patients or controls.
Conclusions
History of SARS-CoV-2 infection was significantly associated with severe systemic AEs following dose 1 of mRNA COVID-19 vaccine; the effect varied by vaccine received. Most participants who experienced severe systemic AEs following dose 1 did not require medical attention of any kind for symptoms following dose 2. Vaccine providers can use these findings to counsel patients who had pre-vaccination SARS-CoV-2 infection histories, experienced severe systemic AEs following dose 1, and are considering not receiving additional mRNA COVID-19 vaccine doses.
Background
In December, 2020, two mRNA-based COVID-19 vaccines were authorised for use in the USA. We aimed to describe US surveillance data collected through the Vaccine Adverse Event Reporting System (VAERS), a passive system, and v-safe, a new active system, during the first 6 months of the US COVID-19 vaccination programme.
Methods
In this observational study, we analysed data reported to VAERS and v-safe during Dec 14, 2020, to June 14, 2021. VAERS reports were categorised as non-serious, serious, or death. Reporting rates were calculated using numbers of COVID-19 doses administered as the denominator. We analysed v-safe survey reports from days 0–7 after vaccination for reactogenicity, severity (mild, moderate, or severe), and health impacts (ie, unable to perform normal daily activities, unable to work, or received care from a medical professional).
Findings
During the study period, 298 792 852 doses of mRNA vaccines were administered in the USA. VAERS processed 340 522 reports: 313 499 (92·1%) were non-serious, 22 527 (6·6%) were serious (non-death), and 4496 (1·3%) were deaths. Over half of 7 914 583 v-safe participants self-reported local and systemic reactogenicity, more frequently after dose two (4 068 447 [71·7%] of 5 674 420 participants for local reactogenicity and 4 018 920 [70·8%] for systemic) than after dose one (4 644 989 [68·6%] of 6 775 515 participants for local reactogenicity and 3 573 429 [52·7%] for systemic). Injection-site pain (4 488 402 [66·2%] of 6 775 515 participants after dose one and 3 890 848 [68·6%] of 5 674 420 participants after dose two), fatigue (2 295 205 [33·9%] participants after dose one and 3 158 299 participants [55·7%] after dose two), and headache (1 831 471 [27·0%] participants after dose one and 2 623 721 [46·2%] participants after dose two) were commonly reported during days 0–7 following vaccination. Reactogenicity was reported most frequently the day after vaccination; most reactions were mild. More reports of being unable to work, do normal activities, or of seeking medical care occurred after dose two (1 821 421 [32·1%]) than after dose one (808 963 [11·9%]); less than 1% of participants reported seeking medical care after vaccination (56 647 [0·8%] after dose one and 53 077 [0·9%] after dose two).
Interpretation
Safety data from more than 298 million doses of mRNA COVID-19 vaccine administered in the first 6 months of the US vaccination programme show that most reported adverse events were mild and short in duration.
Funding
US Centers for Disease Control and Prevention.
The Centers for Disease Control and Prevention (CDC) and the U.S. Food and Drug Administration (FDA) conduct post-licensure vaccine safety monitoring using the Vaccine Adverse Event Reporting System (VAERS), a spontaneous (or passive) reporting system. This means that after a vaccine is approved, CDC and FDA continue to monitor safety while it is distributed in the marketplace for use by collecting and analyzing spontaneous reports of adverse events that occur in persons following vaccination. Various methods and statistical techniques are used to analyze VAERS data, which CDC and FDA use to guide further safety evaluations and inform decisions around vaccine recommendations and regulatory action. VAERS data must be interpreted with caution due to the inherent limitations of passive surveillance. VAERS is primarily a safety signal detection and hypothesis generating system. Generally, VAERS data cannot be used to determine if a vaccine caused an adverse event. VAERS data interpreted alone or out of context can lead to erroneous conclusions about cause and effect as well as the risk of adverse events occurring following vaccination. CDC makes VAERS data available to the public and readily accessible online. We describe fundamental vaccine safety concepts, provide an overview of VAERS for healthcare professionals who provide vaccinations and might want to report or better understand a vaccine adverse event, and explain how CDC and FDA analyze VAERS data. We also describe strengths and limitations, and address common misconceptions about VAERS. Information in this review will be helpful for healthcare professionals counseling patients, parents, and others on vaccine safety and benefit-risk balance of vaccination.
Copyright © 2015. Published by Elsevier Ltd.
The Vaccine Safety Datalink (VSD) is a collaborative project between the Centers for Disease Control and Prevention (CDC) and 9 health care organizations. Established in 1990, VSD is a vital resource informing policy makers and the public about the safety of vaccines used in the United States. Large linked databases are used to identify and evaluate adverse events in over 9 million individuals annually. VSD generates rapid, important safety assessments for both routine vaccinations and emergency vaccination campaigns. VSD monitors safety of seasonal influenza vaccines in near-real time, and provided essential information on the safety of monovalent H1N1 vaccine during the 2009 pandemic. VSD investigators have published important studies demonstrating that childhood vaccines are not associated with autism or other developmental disabilities. VSD prioritizes evaluation of new vaccines; searches for possible unusual health events after vaccination; monitors vaccine safety in pregnant women; and has pioneered development of biostatistical research methods.
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