Indirect Protection from Vaccinating Children against Influenza A Virus Infection in Households

Tim K Tsang; Can Wang; Vicky J Fang; Ranawaka A P M Perera; Hau Chi So; Dennis K M Ip; J S Malik Peiris; Gabriel M Leung; Simon Cauchemez; Benjamin J Cowling

doi:10.3390/v14102097

Indirect Protection from Vaccinating Children against Influenza A Virus Infection in Households

Viruses. 2022 Sep 21;14(10):2097. doi: 10.3390/v14102097.

Authors

Tim K Tsang^{1

2}, Can Wang¹, Vicky J Fang¹, Ranawaka A P M Perera^{1

3}, Hau Chi So¹, Dennis K M Ip¹, J S Malik Peiris^{1

3}, Gabriel M Leung^{1

2}, Simon Cauchemez⁴, Benjamin J Cowling^{1

2}

Affiliations

¹ WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
² Laboratory of Data Discovery for Health Limited, Hong Kong Science and Technology Park, New Territories, Hong Kong, China.
³ HKU-Pasteur Research Pole, The University of Hong Kong, Hong Kong, China.
⁴ Mathematical Modelling of Infectious Diseases Unit, Institut Pasteur, UMR2000, CNRS, 75015 Paris, France.

Abstract

Influenza vaccination is an important intervention to prevent influenza virus infection. Our previous analysis suggested that indirect protection is limited in an influenza B epidemic in Hong Kong. We further analyzed six influenza A epidemics to determine such potential. We applied a statistical model to estimate household transmission dynamics in the 3 influenza A(H3N2) and 3 pandemic influenza A(H1N1) epidemics. Then, we estimated the reduction in infection risk among unvaccinated household members when all children in households are vaccinated, with different assumptions on vaccine efficacy (VE). In the optimal scenario that VE was 70%, the reduction to the total probability of infection was only marginal, with relative probabilities ranged from 0.91-0.94 when all children in households were vaccinated because community was by far the main source of infection during the six epidemics in our study. The proportion of cases attributed to household transmission was 10% (95% CrI: 7%, 13%). Individual influenza vaccination is important even when other household members are vaccinated, given the degree of indirect protection is small.

Keywords: indirect protection; influenza; vaccination.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Child
Humans
Influenza A Virus, H1N1 Subtype*
Influenza A Virus, H3N2 Subtype
Influenza Vaccines*
Influenza, Human* / epidemiology
Influenza, Human* / prevention & control
Vaccination

Substances

Influenza Vaccines

Grants and funding

This study was supported by the Research Fund for the Control of Infectious Diseases of the Health, Welfare and Food Bureau of the Hong Kong SAR Government (grant CHP-CE-03), the Theme-based Research Scheme project no. T11-712/19N from the Hong Kong Government, the Health and Medical Research Fund, Food and Health Bureau, Government of the Hong Kong Special Administrative Region (grant no. 05190097), and the Laboratory of Excellence Integrative Biology of Emerging Infectious Diseases (research funding to SC), AXA Research Fund to SC. The funding bodies had no role in study design, data collection and analysis, preparation of the manuscript, or the decision to publish.