Infant Pneumococcal Carriage During Influenza, RSV, and hMPV Respiratory Illness Within a Maternal Influenza Immunization Trial.

Alastair F Murray,Jane Kuypers,Janet A Englund,Joanne Katz,Helen Y Chu,Subarna K Khatry,Steven C Leclerq,James M Tielsch

doi:10.1093/infdis/jiz212

Abstract

In this post-hoc analysis of midnasal pneumococcal carriage in a community-based, randomized prenatal influenza vaccination trial in Nepal with weekly infant respiratory illness surveillance, 457 of 605 (75.5%) infants with influenza, respiratory syncytial virus (RSV), or human metapneumovirus (hMPV) illness had pneumococcus detected. Pneumococcal carriage did not impact rates of lower respiratory tract disease for these 3 viruses. Influenza-positive infants born to mothers given influenza vaccine had lower pneumococcal carriage rates compared to influenza-positive infants born to mothers receiving placebo (58.1% versus 71.6%, P = 0.03). Maternal influenza immunization may impact infant acquisition of pneumococcus during influenza infection. Clinical Trials Registration. NCT01034254.

Highlights

While Streptococcus pneumoniae is often detected in the nasopharyngeal flora, colonization with this organism is prerequisite to the development of clinically significant invasive pneumococcal disease (IPD)
High rates of pneumococcal carriage were observed with influenza, respiratory syncytial virus (RSV), and human metapneumovirus (hMPV) illness episodes in a birth cohort of infants in rural Nepal prior to the introduction of infant pneumococcal vaccination
Rates of pneumococcal colonization were significantly decreased in influenza-infected infants born to mothers who received influenza vaccine compared to placebo

Summary

Introduction

While Streptococcus pneumoniae is often detected in the nasopharyngeal flora, colonization with this organism is prerequisite to the development of clinically significant invasive pneumococcal disease (IPD). Two decades of experience with a multivalent pneumococcal conjugate vaccine has shown a substantial reduction in the burden of IPD in infants globally. A time-series analysis of the 7-valent pneumococcal conjugate vaccine in South African children younger than 5 years showed a significant reduction in all pneumonia hospital admissions [6]. Inactivated influenza vaccine is often not administered until later in infancy, leaving a window of vulnerability to influenza disease during the first months of life. Our study observed respiratory illness in a birth cohort of infants younger than 6 months in rural Nepal during the period prior to implementation of pneumococcal vaccination in any age group. We studied pneumococcal colonization rates and respiratory illness severity for 3 viruses with a high burden of disease in young infants: influenza, RSV, and hMPV. We further sought to investigate the effect of influenza immunization during pregnancy on pneumococcal carriage in infant influenza illness episodes

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Conclusion