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Volume 28, Number 5—May 2022

Determining Existing Human Population Immunity as Part of Assessing Influenza Pandemic Risk

Jonathan Tin Lai Cheung, Tim K. Tsang, Hui-ling Yen, Ranawaka A.P.M. Perera, Chris Ka Pun Mok, Yong Ping Lin, Benjamin J. Cowling, and Malik PeirisComments to Author 
Author affiliations: University of Hong Kong, Hong Kong (J.T.L. Cheung, T.K. Tsang, H. Yen, R.A.P.M. Perera, C.K.P. Mok, B.J. Cowling, M. Peiris); Chinese University of Hong Kong, Hong Kong (C.K.P. Mok); First Affiliated Hospital of Guangzhou Medical University, Guangdong, China (Y.P. Lin)

Main Article

Table 4

Estimations of overall population-level immunity against historical H2 and H1 pandemic viruses and the potential effect of population immunity on reproduction number among persons in Hong Kong, China*

Virus strain Proportion of population immune (95% CI) Relative reduction in R0 (95% CI) Smallest R0 needed to cause pandemic (95% CI)
A/Singapore/1/1957 (H2N2)
0.37 (0.346–0.394)
0.321 (0.295–0.348)
1.472 (1.419–1.535)
A/California/04/2009 (H1N1) 0.117 (0.098–0.14) 0.115 (0.096–0.138) 1.13 (1.106–1.16)

*Serum samples for testing antibodies to the 1957 virus were collected in 2011 and those for testing antibodies to the 2009 virus were collected in 2008–2009.

Main Article

Page created: February 24, 2022
Page updated: April 19, 2022
Page reviewed: April 19, 2022
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