Perinatal Outcomes of Asynchronous Influenza Vaccination, Ceará, Brazil, 2013-2018.

José Q Filho,Álvaro M Leite,Aldo A.M Lima,Alberto M Soares,Vânia A.F Viana,Francisco S Junior,Jason A Papin,Sean R Moore,Simone A Herron,Kunaal S Sarnaik,Hunter L Newland,Jaqueline S.V Burgoa,Thaisy B.R Lima,Gabriel F Hanson

doi:10.3201/eid2709.203791

Abstract

In Ceará, Brazil, seasonal influenza transmission begins before national annual vaccination campaigns commence. To assess the perinatal consequences of this misalignment, we tracked severe acute respiratory infection (SARI), influenza, and influenza immunizations during 2013–2018. Among 3,297 SARI cases, 145 (4.4%) occurred in pregnant women. Statewide vaccination coverage was >80%; however, national vaccination campaigns began during or after peak influenza season. Thirty to forty weeks after peak influenza season, birthweights decreased by 40 g, and rates of prematurity increased from 10.7% to 15.5%. We identified 61 children born to mothers with SARI during pregnancy; they weighed 10% less at birth and were more likely to be premature than 122 newborn controls. Mistiming of influenza vaccination campaigns adversely effects perinatal outcomes in Ceará. Because Ceará is the presumptive starting point for north-to-south seasonal influenza transmission in Brazil, earlier national immunization campaigns would provide greater protection for pregnant women and their fetuses in Ceará and beyond.

Highlights

In Ceará, Brazil, seasonal influenza transmission begins before national annual vaccination campaigns commence
We linked the SINAN and Sistema de Informações Sobre Nascidos Vivos (SINASC) databases to identify 61 children born to mothers who had >1 severe acute respiratory infection (SARI) during pregnancy
Cases occurred predominantly in younger children, especially children

Summary

Introduction

In Ceará, Brazil, seasonal influenza transmission begins before national annual vaccination campaigns commence. Because Ceará is the presumptive starting point for north-to-south seasonal influenza transmission in Brazil, earlier national immunization campaigns would provide greater protection for pregnant women and their fetuses in Ceará and beyond. Influenza epidemics are associated with excess rates of pneumonia, related hospitalizations, and death [4] Pregnant women and their infants are at heightened risk for severe influenza [5,6]. The state capital, which has a population of 2.7 million, has seasonal influenza peaks 2–3 months earlier than in South and Southeast Brazil [16,17] Despite these well-described epidemiologic differences, the entire country uses the same vaccination schedule, which is usually concurrent with or after peak influenza activity in the semiarid region (Figure 1). Because vaccine-acquired immunity against influenza usually develops 2 weeks after immunization, we hypothesized that pregnant women and their fetuses in the semiarid region might not be adequately protected against influenza

Methods

Results

Conclusion