Effectiveness of one and two doses of acellular pertussis vaccines against laboratory-confirmed pertussis requiring hospitalisation in infants: Results of the PERTINENT sentinel surveillance system in six EU/EEA countries, December 2015 - December 2019.

Abstract

BACKGROUND:

Monitoring effectiveness of pertussis vaccines is necessary to adapt vaccination strategies. PERTINENT, Pertussis in Infants European Network, is an active sentinel surveillance system implemented in 35 hospitals across six EU/EEA countries. We aim to measure pertussis vaccines effectiveness (VE) by dose against hospitalisation in infants aged <1 year.

METHODS:

From December 2015 to December 2019, participating hospitals recruited all infants with pertussis-like symptoms. Cases were vaccine-eligible infants testing positive for Bordetella pertussis by PCR or culture; controls were those testing negative to all Bordetella spp. For each vaccine dose, we defined an infant as vaccinated if she/he received the corresponding dose >14 days before symptoms. Unvaccinated were those who did not receive any dose. We calculated (one-stage model) pooled VE as 100*(1-odds ratio of vaccination) adjusted for country, onset date (in 3-month categories) and age-group (when sample allowed it).

RESULTS:

Of 1,393 infants eligible for vaccination, we included 259 cases and 746 controls. Median age was 16 weeks for cases and 19 weeks for controls (p < 0.001). Median birth weight and gestational age were 3,235 g and week 39 for cases, 3,113 g and week 39 for controls. Among cases, 119 (46 %) were vaccinated: 74 with one dose, 37 two doses, 8 three doses. Among controls, 469 (63 %) were vaccinated: 233 with one dose, 206 two doses, 30 three doses. Adjusted VE after at least one dose was 59 % (95 %CI: 36-73). Adjusted VE was 48 % (95 %CI: 5-71) for dose one (416 eligible infants) and 76 % (95 %CI: 43-90) for dose two (258 eligible infants). Only 42 infants were eligible for the third dose.

CONCLUSIONS:

Our results suggest moderate one-dose and two-dose VE in infants. Larger sample size would allow more precise estimates for dose one, two and three.

• Authors: Lore Merdrignac, Fatima Aït El Belghiti, Elisabetta Pandolfi, Lesly Acosta, Kateřina Fabiánová, Adele Habington, Manuel García Cenoz, Håkon Bøås, Julie Toubiana, Alberto E Tozzi, Iolanda Jordan, Jana Zavadilová, Niam O'Sullivan, Ana Navascués, Elmira Flem, Ilena Croci, Mireia Jané, Pavla Křížová, Suzanne Cotter, Leticia Fernandino, Terese Bekkevold, Carmen Muñoz-Almagro, Sabrina Bacci, Piotr Kramarz, Esther Kissling, Camelia Savulescu, Renacoq Group, PERTINENT Group
• Journal: Vaccine (Vaccine) Vol. 42 Issue 9 Pg. 2370-2379 (Apr 02 2024) ISSN: 1873-2518 [Electronic] Netherlands
• PMID: 38472070 (Publication Type: Journal Article)
• Copyright: Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Chemical References

• Pertussis Vaccine

Topics

• Infant
• Female
• Humans
• Whooping Cough (epidemiology, prevention & control)
• Sentinel Surveillance
• Case-Control Studies
• Pertussis Vaccine
• Vaccination (methods)
• Hospitalization