Indirect Effectiveness of Influenza Vaccination: A Systematic Review of Cluster-randomized Controlled Trials
Notice bibliographique
Résumé
Abstract Rationale: Indirect vaccine effectiveness (IVE) is the measure of protection conferred from vaccinated individuals to others who are susceptible to infection. Conceptually, by vaccinating sufficient numbers of persons against influenza and reducing primary infections and/or contagiousness, the risk of unvaccinated persons developing influenza decreases. To inform public health expectations, we conducted a systematic review of cluster-randomized influenza vaccination trials designed to measure IVE. Methods: We searched MEDLINE and EMBASE for relevant articles from inception through September 23, 2024. We identified cluster-randomized, controlled trials published in English that measured IVE against laboratory-confirmed influenza illness (LCI) outcomes in humans and reported overall IVE as a percentage or provided sufficient data to calculate it. We then extracted and collated article data to analyze studies and report both indirect and direct vaccine effectiveness. Results: We identified four relevant publications, describing seven separate influenza vaccine trials: one article from Canada described a single trial conducted in 2008-09, two articles from Senegal described three separate trials conducted from 2008-11, and one article from India described three separate trials conducted from 2009-12. Among the seven trials, four (57%) measured significant direct vaccine effectiveness ranging from 25.6% (95% CI 6.8% to 40.6%) to 74.2% (95% CI 57.8% to 84.3%). Two (29%) of the trials measured significant IVE ranging from 38.1% (95% CI 7.4% to 58.6%) to 61% (95% CI 8%, 83%), while five (71%) did not find significant evidence of IVE (with 95% CI crossing the null). Each of the five studies without significant IVE reported mismatch between a vaccine strain and a circulating viral strain, including one study conducted during the emergence of the 2009 pandemic influenza A (H1N1). Three studies that measured significant direct vaccine effectiveness failed to measure significant IVE. Conclusions: Our study indicates that seasonal influenza vaccination programs may not necessarily confer measurable indirect protections to unvaccinated populations. Among the seven published cluster-randomized influenza vaccination trials, five failed to detect any significant IVE, with each implicating vaccine mismatch against circulating viruses as contributing to the findings. Furthermore, among the four studies that measured significant overall direct influenza vaccine effectiveness, three did not measure significant IVE. In the future, we will expand our analysis to include observational research studies as well as measures of strain-specific IVE. While currently available influenza vaccines are moderately effective at preventing influenza illness among vaccinated persons, they may be inconsistent at conferring indirect protections.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,049 | 0,179 |
| Méta-épidémiologie (sens strict) | 0,003 | 0,002 |
| Méta-épidémiologie (sens large) | 0,019 | 0,017 |
| Bibliométrie | 0,013 | 0,012 |
| Études des sciences et des technologies | 0,001 | 0,002 |
| Communication savante | 0,005 | 0,004 |
| Science ouverte | 0,004 | 0,002 |
| Intégrité de la recherche | 0,003 | 0,003 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,006 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».