Sivan Gazit's research while affiliated with Academic College of Tel Aviv-Yafo and other places

Publications (57)

Article
Full-text available
This is the first Israeli case report of mpox (monkeypox) disease, as it is manifested in the current outbreak. This manuscript depicts two detailed patient journeys of Israeli men in their 30s who were diagnosed in recent months, depicting their symptoms, presumed exposure, and outcomes. The two cases were atypical compared to the clinical present...
Article
Background: The short-term effectiveness of a 2-dose regimen of the BioNTech/Pfizer BNT162b2 vaccine for adolescents has been demonstrated. However, little is known about the long-term effectiveness in this age group. It is known, however, that waning of vaccine-induced immunity against infection in adult populations is evident within a few months...
Article
Despite increasing awareness for diagnosing autism spectrum disorder (ASD) and initiating treatments early in life, many children and adolescents continue to be diagnosed at a relatively older age. Focusing on children who first received an ASD diagnosis at age six or older, this study aimed to describe the symptoms that parents reported when ASD w...
Article
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This report describes the development of a data-driven approach for identifying individuals who tested negative to a SARS-CoV-2 infection, despite their residence with individuals who had confirmed infections. Household studies have demonstrated efficiency in evaluating exposure to SARS-CoV-2. Leveraging earlier studies based on the household unit,...
Article
Background The effectiveness of the second BNT162b2 (Pfizer–BioNTech) mRNA COVID-19 booster vaccine dose (ie, fourth inoculation) is well established, but its safety has yet to be fully understood. The absence of sufficient vaccine safety information is one of the key contributors to vaccine hesitancy. In this study, we aimed to evaluate the safety...
Article
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Objective: Evaluating the prevalence of long-COVID symptoms in patients with a history of mild or asymptomatic infection with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and the factors associated with developing long-COVID. Design: A nationwide cohort study. Using a centralized database, we have identified patients with and wit...
Article
Background Data regarding the long-term protection afforded by vaccination for the SARS-CoV-2 infection are essential for allocation of scarce vaccination resources worldwide. Methods We conducted a retrospective cohort study aimed at studying the kinetics of IgG antibodies against SARS-CoV-2 in COVID-19-naïve patients fully vaccinated with two do...
Article
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The aim of this real-life, big data population-based study was to evaluate differences in symptomatic presentation of children infected with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) between the third and fourth waves of the pandemic in Israel, dominated by the Alpha and Delta variants, respectively. Our cohort included all child...
Article
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Objectives Data regarding women infected with SARS-CoV-2 during early trimesters are scarce. We aimed to assess preterm birth (PTB) and small-for-gestational-age (SGA) rates in a large and unselected cohort by trimester at infection and overall. Design A retrospective cohort study including all women with a positive SARS-CoV-2 RT-PCR test during a...
Preprint
Describing patient journeys of monkeypox in a developed country, as it is manifested in the current outbreak, as well as rapidly sharing information as a lesson from the early days of the SARS-CoV-2 pandemic.
Preprint
Objectives There are paucity of studies examining naturally acquired immunity against SARS-CoV-2 in children and adolescents, though they are generally the last group to be afforded the vaccine, and a significant portion of them are still unvaccinated. This study examined the duration of protection conferred by a previous SARS-CoV-2 infection among...
Article
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Halting the rapid clinical deterioration, marked by arterial hypoxemia, is among the greatest challenges clinicians face when treating COVID-19 patients in hospitals. While it is clear that oxygen measures and treatment procedures describe a patient’s clinical condition at a given time point, the potential predictive strength of the duration and ex...
Preprint
Newly emerging SARS-CoV-2 variants of concern (VOCs) play a major role in the persistence of the coronavirus disease 2019 (COVID-19) pandemic. While these VOCs are characterized by extraordinary evolutionary leaps and evasion from previously acquired immunity, their origins remain mostly unknown. In this study, we paired electronic health records o...
Article
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The duration of protection of the third (booster) dose of the BioNTech/Pfizer BNT162b2 mRNA Coronavirus Disease 2019 vaccine has been the subject of recent investigations, as global discussions around the necessity and effectiveness of a fourth dose are already underway. By conducting a retrospective study implementing a test-negative case-control...
Preprint
COVID-19 remains a global concern due to vaccine protection waning and the emergence of immune-evasive variants. While the effectiveness of a second booster vaccine dose (i.e., fourth inoculation) is well proven, its safety has yet to be fully understood, and vaccine compliance remains low. We conducted a prospective observational study to compare...
Article
Despite extensive technological advances in recent years, objective and continuous assessment of physiologic measures after vaccination is rarely performed. We conducted a prospective observational study to evaluate short-term self-reported and physiologic reactions to the booster BNT162b2 mRNA (Pfizer-BioNTech, https://www.pfizer.com) vaccine dose...
Article
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Objective To examine the relative effectiveness of a fourth dose of the Pfizer-BioNTech mRNA (BNT162b2) vaccine compared with three vaccine doses over the span of 10 weeks. Design Retrospective, test negative, case-control study, with a matched analysis and an unmatched multiple tests analysis. Setting Nationally centralised database of Maccabi H...
Article
Background Waning of protection against infection with SARS-CoV-2 conferred by 2 doses of the BNT162b2 vaccine begins shortly after inoculation and becomes substantial within four months. With that, the impact of prior infection on incident SARS-CoV-2 reinfection is unclear. Therefore, we examined the long-term protection of naturally acquired immu...
Preprint
Objectives The rapid spread of the Omicron variant (B.1.1.529) alongside evidence of a relatively rapid waning of the third dose prompted Israel to administer a fourth dose of the BNT162b2 vaccine on January 2022. Thus far, sufficient real-world evidence demonstrating the effectiveness of a fourth dose against infection and severe COVID-19 are lack...
Article
Full-text available
The BNT162b2 COVID-19 vaccine has been shown to reduce viral load of breakthrough infections (BTIs), an important factor affecting infectiousness. This viral-load protective effect has been waning with time post the second vaccine and later restored with a booster shot. It is currently unclear though for how long this regained effectiveness lasts....
Preprint
The duration of protection of the third (booster) dose of the BioNTech/Pfizer BNT162b2 mRNA Coronavirus Disease 2019 vaccine has yet to be sufficiently researched, while global discussions around the necessity and effectiveness of a fourth dose are already underway. By conducting a retrospective study implementing a test-negative case-control desig...
Article
Background: There is insufficient evidence regarding the magnitude and durability of protection conferred by a combined effect of naturally acquired immunity after SARS-CoV-2 infection and vaccine-induced immunity. Objective: To compare the incidence rate of SARS-CoV-2 reinfection in previously infected persons to that of previously infected per...
Article
The individual-level effectiveness of vaccines against COVID-19 is well established. However, few studies have examined vaccine effectiveness against transmission. We used a chain binomial model to estimate the effectiveness of vaccination with BNT162b2 (Pfizer-BioNTech mRNA-based vaccine) against household transmission of SARS-CoV-2 in Israel befo...
Article
BACKGROUND Although 3,000,000 Americans are afflicted with Inflammatory Bowel Disease (IBD) encompassing Crohn’s Disease (CD) and Ulcerative Colitis (UC)1, timely diagnosis is a challenge due to non-specific and overlapping symptoms.2 More than 20% of patients may be initially misdiagnosed3 causing delayed diagnosis and treatment, potentially leadi...
Preprint
Full-text available
Background: The short-term effectiveness of a two-dose regimen of the BioNTech/Pfizer mRNA BNT162b2 vaccine for adolescents has been demonstrated. However, little is known about the long-term effectiveness in this age group. It is known, though, that waning of vaccine-induced immunity against infection in adult populations is evident within a few m...
Preprint
Full-text available
The BNT162b2 COVID-19 vaccine has been shown to reduce viral load of breakthrough infections (BTIs), an important factor affecting infectiousness. This viral-load protective effect has been waning with time post the second vaccine and later restored with a booster shot. It is currently unclear though for how long this regained effectiveness lasts....
Article
Full-text available
The effectiveness of the coronavirus disease 2019 (COVID-19) BNT162b2 vaccine in preventing disease and reducing viral loads of breakthrough infections (BTIs) has been decreasing, concomitantly with the rise of the Delta variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, it is unclear whether the observed decreased ef...
Article
Full-text available
Background Red blood cell distribution width (RDW) has been assessed during COVID-19 patient hospitalization, however, further research should be done to evaluate RDW from routine community blood tests, before infection, as a risk factor for COVID-19 related hospitalization and mortality. Patients and methods RDW was measured as a predictor along...
Article
Importance With the evidence of waning immunity of the mRNA vaccine BNT162b2 (Pfizer-BioNTech), a nationwide third-dose (booster) vaccination campaign was initiated in Israel during August 2021; other countries have begun to administer a booster shot as well. Objective To evaluate the initial short-term additional benefit of a 3-dose vs a 2-dose r...
Article
Background While BNT162b2 vaccine-efficacy analyses were previously published, the effectiveness of the vaccine in preventing COVID-19 given confirmed exposure has not been previously demonstrated, even though it has policy implications, such as the need for self-quarantine when exposure has occurred or protective measures for vaccinated individual...
Article
Full-text available
The short-term effectiveness of a two-dose regimen of the BioNTech/Pfizer mRNA BNT162b2 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine was widely demonstrated. However, long term effectiveness is still unknown. Leveraging the centralized computerized database of Maccabi Healthcare Services (MHS), we assessed the correlation be...
Article
Quantifying the detection rate of the widely used SARS-CoV-2 RT-qPCR test and its dependence on patient demographics and disease progression is key in designing epidemiological strategies. Analyzing 843,917 test results of 521,696 patients, for each patient, a ‘positivity period’ was defined between COVID-19 diagnosis and last positive test result....
Preprint
Background: The rapid rise in hospitalizations associated with the Delta-driven COVID-19 resurgence, and the imminent risk of hospital overcrowding, led the Israeli government to initialize a national third (booster) COVID-19 vaccination campaign in early August 2021, offering the BNT162b2 mRNA vaccine to individuals who received their second dose...
Preprint
Full-text available
The BNT162b2 vaccine showed high real-life effectiveness both at preventing disease and in reducing viral loads of breakthrough infections, but coincidental with the rise of the Delta-variant SARS-CoV2, these protective effects have been decreasing, prompting a third, booster, vaccine inoculation. Here, analyzing viral loads of over 11,000 infectio...
Preprint
With the evidence of waning immunity of the BNT162b2 vaccine, a national third dose vaccination campaign was initiated in Israel during August 2021; other countries have announced their intention to administer a booster shot as well. Leveraging data from Maccabi Healthcare Services, we conducted a preliminary retrospective study aimed at evaluating...
Preprint
Background: Reports of waning vaccine-induced immunity against COVID-19 have begun to surface. With that, the comparable long-term protection conferred by previous infection with SARS-CoV-2 remains unclear. Methods: We conducted a retrospective observational study comparing three groups: (1)SARS-CoV-2-naive individuals who received a two-dose regim...
Article
Current COVID-19 screening efforts mainly rely on reported symptoms and the potential exposure to infected individuals. Here, we developed a machine-learning model for COVID-19 detection that uses four layers of information: (i) sociodemographic characteristics of the individual, (ii) spatio-temporal patterns of the disease, (iii) medical condition...
Article
Full-text available
Mass vaccination has the potential to curb the current COVID-19 pandemic by protecting individuals who have been vaccinated against the disease and possibly lowering the likelihood of transmission to individuals who have not been vaccinated. The high effectiveness of the widely administered BNT162b vaccine from Pfizer–BioNTech in preventing not onl...
Article
Deployment of the BNT162b2 mRNA Covid-19 Vaccine in Israel began in December 2020. This is a retrospective analysis of serological data, showing SARS-CoV-2 anti-S IgG kinetics in 116 Israeli health care workers receiving BNT162b2. Sero-conversion occurred in 14 days in all study participants, with IgG levels peaking approximately 30 days after init...
Preprint
Full-text available
The short-term effectiveness of a two-dose regimen of the BioNTech/Pfizer mRNA BNT162b2 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine was widely demonstrated. However, long term effectiveness is still unknown. A nationwide vaccination campaign was initiated early in Israel, allowing for a real-world evaluation of the interact...
Preprint
Full-text available
The individual-level effectiveness of vaccines against clinical disease caused by SARS-CoV-2 is well-established. However, few studies have directly examined the effect of COVID-19 vaccines on transmission. We quantified the effectiveness of vaccination with BNT162b2 (Pfizer-BioNTech mRNA-based vaccine) against household transmission of SARS-CoV-2...
Preprint
Importance While the mRNA BNT162b2 vaccine effectiveness was demonstrated in general population, the question of effectiveness given confirmed exposure has yet been answered, though it has policy implications, as the need for self-quarantine when exposed and protective measures for vaccinated in high-risk areas. Objective Assessing the BNT162b2 vac...
Article
Full-text available
Importance The BNT162b2 vaccine showed high efficacy against COVID-19 in a phase III randomized clinical trial. A vaccine effectiveness evaluation in a real-world setting is needed. Objective To assess the short-term effectiveness of the first dose of the BNT162b2-vaccine against SARS-CoV-2 infection 13 to 24 days after immunization in a real-worl...
Article
Background COVID-19 mRNA vaccines were shown to be highly efficacious in preventing the disease in randomized controlled trials; nonetheless, evidence on the real-world effectiveness of this vaccine is limited. Study objective was to evaluate the effectiveness of BNT162b2 vaccine in preventing SARS-CoV-2 infection and COVID-19-related hospitalizati...
Article
Full-text available
Beyond their substantial protection of individual vaccinees, coronavirus disease 2019 (COVID-19) vaccines might reduce viral load in breakthrough infection and thereby further suppress onward transmission. In this analysis of a real-world dataset of positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) test results after inoculation...
Preprint
Following the widespread vaccination program for COVID-19 carried out in Israel, a survey was conducted to preliminarily assess behavior changes in the vaccinated population, prior to the expected upcoming policy change as to mask wearing and social distancing regulation in Israel. 200 people answered at least one question pertaining to preventive...
Preprint
Full-text available
Mass vaccination has the potential to curb the current COVID-19 pandemic by protecting vaccinees from the disease and possibly lowering the chance of transmission to unvaccinated individuals. The high effectiveness of the widely-administered BNT162b vaccine in preventing not only the disease but also infection suggests a potential for a population-...
Preprint
Full-text available
Vaccinations are considered the major tool to curb the current SARS-CoV-2 pandemic. A randomized placebo-controlled trial of the BNT162b2 vaccine has demonstrated a 95% efficacy in preventing COVID-19 disease. These results are now corroborated with statistical analyses of real-world vaccination rollouts, but resolving vaccine effectiveness across...
Preprint
With more than 100 million confirmed COVID-19 cases as of March 2021, reinfection is still considered to be rare. In light of increasing reports of reinfected COVID-19 patients, the need to better understand the real risk for reinfection is critical, with potential effects on public health policies aimed at containing the spread of SARS-CoV-2. In t...
Preprint
Deployment of the BNT162b2 mRNA Covid-19 Vaccine in Israel began in December 2020. This is a retrospective analysis of serological data, describing SARS-CoV-2 anti-S IgG kinetics in 116 Israeli healthcare workers administrated the BNT162b2 vaccine. Seroconversion occurred by day 14 in all individuals, with IgG levels peaking approximately 30 days p...
Preprint
Current efforts for COVID-19 screening mainly rely on reported symptoms and potential exposure to infected individuals. Here, we developed a machine-learning model for COVID-19 detection that utilizes four layers of information: 1) sociodemographic characteristics of the tested individual, 2) spatiotemporal patterns of the disease observed near the...
Preprint
Full-text available
Beyond their substantial protection of individual vaccinees, it is hoped that the COVID-19 vaccines would reduce viral load in breakthrough infections thereby further suppress onward transmission. Here, analyzing positive SARS-CoV-2 test results following inoculation with the BNT162b2 mRNA vaccine, we find that the viral load is reduced 4-fold for...
Preprint
Background BNT162b2 vaccines showed high efficacy against COVID-19 in a randomized controlled phase-III trial. A vaccine effectiveness evaluation in real life settings is urgently needed, especially given the global disease surge. Hence, we assessed the short-term effectiveness of the first dose of BNT162b2-vaccine against SARS-CoV-2 infection. Giv...

Citations

... 8 Vaccine effectiveness (VE) has been found to decline at 6 months after the second dose of the BNT162b2 vaccine in adults 9,10 and adolescents. 11 VE was also reduced during periods predominated by Omicron BA.1, which contains more than 30 mutations in its S protein, enabling dramatic neutralisation escape. 12,13 Further Omicron sublineages have emerged, with a BA.2 epidemic wave affecting Hong Kong in January 2022, whilst BA.5 has become predominant worldwide since July 2022. ...
... Another retrospective cohort study analyzed 5609 individuals taking immune suppressants and found that three doses of BNT162b2 and mRNA-1273 provide effectiveness of 50% and 60% against the Omicron variant, respectively [116]. Furthermore, three doses of BNT162b2 and mRNA-1273 can both provide effectiveness of 87% against hospitalization caused by the Omicron variant in immunosuppressed individuals [117]. ...
... The available data showed that asymptomatic infected cases had a significantly reduced risk of long-term COVID-19 consequences compared to symptomatic infected cases. There is an increasing amount of evidence showing that the long-term consequences of COVID-19 are related to the severity of SARS-CoV-2 infection at the time of onset, that is, the more severe the disease, the higher the risk, and the greater the severity, of long-COVID [22,30]. Maddalena Peghin et.al found that a proportional increase in the number of symptoms during the onset of COVID-19 was one of the independent risk factors for post-COVID-19 syndrome [14]. ...
... Another study including 402 pregnant women with SARS-CoV-2 infection in the first or second trimester and 11,705 uninfected women likewise found that infection in the first or second trimester was associated with increased risk of preterm birth, but not increased risk of moderately to extremely preterm birth (here defined as less than 34 weeks gestation), and with a slightly increased risk of fetal or neonatal death [76]. In contrast, a larger retrospective cohort study from Israel including 2753 SARS-CoV-2-infected pregnant women (478 with first trimester infection, 943 with second trimester infection, and 1332 with third trimester infection) found that third trimester infection, but not first or second trimester infection, was associated with increased risk of preterm birth [77]. Another study followed outcomes in 16 first trimester SARS-CoV-2-infected women and found no difference compared to uninfected women [78]. ...
... A major topic of ongoing research is how the emergence of the new SARS-CoV-2 variants impacts a patient's clinical presentation and outcome. New variants have been associated with increased transmission, different clinical features, more severe cases in some instances, and a reduced response to COVID-19 vaccines (14,23). Fever has been shown to be the most commonly reported symptom, and other symptoms vary depending on the virus variant that predominates at specific point in time (19,23). ...
... Whilst we report highly detailed data from two hospitals, this study design lacks the large participant numbers available in some other data-linkage studies, which show VE waning against Omicron and Delta SARS-CoV-2 infection. [30][31][32] Our analysis has several strengths. All COVID-19 vaccinations are available in the UK solely through the NHS without cost or requirement for insurance at the point of delivery. ...
... Among the initially searched 376 documents, 116 duplicate publications were removed; the title and abstract of the remaining 260 documents were screened initially, and 249 irrelevant documents were excluded. The full-texts of the remaining 11 documents were reviewed; then, two opinion articles [24,25], three on the impact of SARS-CoV-2 infection [26][27][28], and one on human rhinovirus [29] were excluded, and the remaining five observational studies [21,[30][31][32][33] were included in this review ( Figure 1). ...
... 48,49 The requirement of re-scheduling of the booster vaccine delivery route is further suggested by the preliminary data on the fourth dose administration of BNT162b2 mRNA vaccine in Israel showing a reinforcement of protection against severe outcomes, but only a short-lived defense against the infection. 50 ...
... Research done by Ingrid Tojersen has shown that the Covid-19 vaccination has been causing the deaths of the elder population [4,5]. Research done by Sivan Gazid and co-authors is confirming that the natural immunity of unvaccinated people is far better protection than Covid-19 vaccines [6]. At this point, it is clear that it is necessary to calculate the effectiveness of Covid-19 as we are proposing. ...
... The vaccine is given intramuscularly (IM) in two doses, 21 days apart [11,12]. A third booster dose is scheduled approximately 6 months after the two-dose regimen, while the administration of a fourth one (four months later) has been proven effective in reducing short-term COVID-19-related outcomes when tested in certain "at-risk" patient groups in several countries [13,14]. ...