Transmission of Bordetella pertussis to young infants

Baylor College of Medicine, Houston, Texas, United States
The Pediatric Infectious Disease Journal (Impact Factor: 3.14). 04/2007; 26(4):293-9. DOI: 10.1097/01.inf.0000258699.64164.6d
Source: PubMed

ABSTRACT Pertussis vaccination has reduced the number of notified cases in industrialized countries from peak years by more than 95%. The effect of recently recommended adult and adolescent vaccination strategies on infant pertussis depends, in part, on the proportion of infants infected by adults and adolescents. This proportion, however, remains unclear, because studies have not been able to determine the source case for 47%-60% of infant cases.
A prospective international multicenter study was conducted of laboratory confirmed infant pertussis cases (aged <or=6 months) and their household and nonhousehold contacts. Comprehensive diagnostic evaluation (including PCR and serology) was performed on all participants independent of symptoms. Source cases were identified and described by relationship to the infant, age and household status.
The study population comprised 95 index cases and 404 contacts. The source of pertussis was identified for 48% of infants in the primary analysis and up to 78% in sensitivity analyses. In the primary analysis, parents accounted for 55% of source cases, followed by siblings (16%), aunts/uncles (10%), friends/cousins (10%), grandparents (6%) and part-time caretakers (2%). The distribution of source cases was robust to sensitivity analyses.
This study provides solid evidence that among infants for whom a source case was identified, household members were responsible for 76%-83% of transmission of Bordetella pertussis to this high-risk group. Vaccination of adolescents and adults in close contact with young infants may thus eliminate a substantial proportion of infant pertussis if high coverage rates can be achieved.

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    ABSTRACT: يعد السعال الديكي أو الشاهوق من األمراض املعدية التي ميكن الوقاية منها أو توقيها بالتطعيم. انخفض ظهور املرض بشدة منذ ظهور لقاح اخلناق، والكزاز، والشاهوق DTP. لوحظ بكثرة إعادة ظهور املرض لدى العديد من األشخاص املطعمني في الدول الغربية منذ 1990م. بعض األسباب التي كانت مسؤولة بشكل رئيسي على حاالت السعال الديكي كانت ضعف جودة اللقاح املقدم، وانخفاض املناعة الناجتة بعد التطعيم، وتالؤم املرض، وتعزيز نظام املراقبة، وتطور التشخيص في املرافق الصحية. أن تشخيص السعال الديكي مهمل وقد ال يالحظ نظراً ً للمظاهر الشاذة في األشخاص احملصنني جزئيا أو األشخاص ضعيفي املناعة. في هذا التقرير نستعرض مراجعات بخصوص عودة السعال الديكي من دول عديدة ومحاولة التحقق من األسباب خلف إعادة ظهور املرض. كما تركز على احلقيقة أن السعال الديكي من األمراض املعدية غير املبلغ عنها إلى اآلن. كما أن اإلحصائيات املقدمة من الدول النامية ال تعكس الصورة احلقيقية للمرض. لذلك، حتتاج هذه الدول إلى تطوير نظام املراقبة. Pertussis or whooping cough is a highly infectious, vaccine preventable disease. The incidence of the disease has greatly been reduced since the introduction of the diphtheria and tetanus toxoids and pertussis (DTP) vaccine. Pertussis resurgence has been observed in highly vaccinated populations of Western countries since 1990s. Poor vaccine quality, waning vaccine induced immunity, pathogen adaptation, and enhanced surveillance as well as advancements in diagnostic facilities are some of the reasons considered responsible for the increased reporting of pertussis cases. Pertussis may have been ignored and unnoticed due to its atypical manifestations in partially immunized population or people with waning immunity. We review the reports of pertussis resurgence from different countries and attempt to investigate reasons behind the reappearance of the disease. Pertussis is still an under reported disease and the available data from the developing countries is not a true picture of the story. Therefore, developing countries need to improve their surveillance systems.
    Saudi medical journal 10/2014; 35(10). · 0.55 Impact Factor
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    ABSTRACT: Recent pertussis outbreaks have prompted re-examination of post-exposure prophylaxis (PEP) strategies, when immunization is not immediately protective. Chemoprophylaxis is recommended to household contacts; however there are concerns of clinical failure and significant adverse events, especially with erythromycin among infants who have the highest disease burden. Newer macrolides offer fewer side effects at higher drug costs. We sought to determine the cost-effectiveness of PEP strategies from the health care payer perspective. A Markov model was constructed to examine 4 mutually exclusive strategies: erythromycin, azithromycin, clarithromycin, or no intervention, stratified by age group of contacts ("infant", "child", and "adult"). Transition probabilities, costs and quality-adjusted life years (QALYs) were derived from the literature. Chronic neurologic sequelae were modeled over a lifetime, with costs and QALYs discounted at 5%. Associated health outcomes and costs were compared, and incremental cost-effectiveness ratios (ICER) were calculated in 2012 Canadian dollars. Deterministic and probabilistic sensitivity analyses were performed to evaluate the degree of uncertainty in the results. Azithromycin offered the highest QALYs in all scenarios. While this was the dominant strategy among infants, it produced an ICER of $16,963 per QALY among children and $2,415 per QALY among adults. Total QALYs with azithromycin were 19.7 for a 5-kg infant, 19.4 for a 10-year-old child, and 18.8 for a 30-year-old adult. The costs of azithromycin PEP among infants, children and adults were $1,976, $132 and $90, respectively. While results were sensitive to changes in PEP effectiveness (11% to 87%), disease transmission (variable among age groups) and hospitalization costs ($379 to $59,644), the choice of strategy remained unchanged. Pertussis PEP is a cost-effective strategy compared with no intervention and plays an important role in contact management, potentially in outbreak situations. From a healthcare payer perspective, azithromycin is the optimal strategy among all contact groups.
    PLoS ONE 01/2015; 10(3):e0119271. DOI:10.1371/journal.pone.0119271 · 3.53 Impact Factor
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    ABSTRACT: Objectifs Décrire la couverture vaccinale de la coqueluche dans la population lyonnaise afin de vérifier l’adéquation avec les recommandations vaccinales en France. Patients et méthodes Entre octobre 2010 et mars 2012, une étude transversale en collaboration avec les laboratoires d’analyses de biologie médicale a inclus 1930 adultes de plus de 19 ans dans la région lyonnaise. Les adultes rapportaient un document preuve (DP) de vaccination pour vérifier le statut vaccinal. Résultats Un pourcentage de 30,3 % (585/1930) des adultes inclus ont rapporté un DP. La couverture vaccinale contre la coqueluche confirmée à l’aide du DP était de 10,7 % [IC 95 % 8,45–13,48] (63/585) et ne variait pas en fonction du sexe (p = 0,57), de l’âge (p = 0,06), ou du niveau d’éducation (p = 0,41). Un pourcentage de of 84,2 % (64/76) [IC 95 % 74,7–91,2] des personnes ayant un projet parental et 83,6 % [IC 95 % 75,6–89,8] (87/104) des personnes en contact avec des enfants de moins de 6 mois ne sont pas à jour de leur vaccination coqueluche. Le statut vaccinal n’était pas confirmé pour 80,0 % (124/155) des personnes pensant être à jour de leur vaccination. Conclusion La stratégie cocooning mise en place depuis 2004 est très peu suivie. La couverture vaccinale de la coqueluche confirmée par un DP chez les adultes pointe l’insuffisance d’adéquation de cette vaccination avec les objectifs. Il est nécessaire de renforcer la politique vaccinale pour ce vaccin de rappel.
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