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Association between the severity of influenza A(H7N9) virus infections and length of the incubation period

journal contribution
posted on 2023-07-14, 05:34 authored by V Virlogeux, J Yang, VJ Fang, L Feng, TK Tsang, H Jiang, P Wu, J Zheng, EHY Lau, Y Qin, Z Peng, JSM Peiris, H Yu, BJ Cowling
Background In early 2013, a novel avian-origin influenza A(H7N9) virus emerged in China, and has caused sporadic human infections. The incubation period is the delay from infection until onset of symptoms, and varies from person to person. Few previous studies have examined whether the duration of the incubation period correlates with subsequent disease severity. Methods and Findings We analyzed data of period of exposure on 395 human cases of laboratory-confirmed influenza A(H7N9) virus infection in China in a Bayesian framework using a Weibull distribution. We found a longer incubation period for the 173 fatal cases with a mean of 3.7 days (95% credibility interval, CrI: 3.4-4.1), compared to a mean of 3.3 days (95% CrI: 2.9-3.6) for the 222 non-fatal cases, and the difference in means was marginally significant at 0.47 days (95% CrI: -0.04, 0.99). There was a statistically significant correlation between a longer incubation period and an increased risk of death after adjustment for age, sex, geographical location and underlying medical conditions (adjusted odds ratio 1.70 per day increase in incubation period; 95% credibility interval 1.47-1.97). Conclusions We found a significant association between a longer incubation period and a greater risk of death among human H7N9 cases. The underlying biological mechanisms leading to this association deserve further exploration.

History

Journal

PLoS ONE

Volume

11

Pagination

e0148506-e0148506

Location

United States

ISSN

1932-6203

eISSN

1932-6203

Language

en

Editor/Contributor(s)

Merler S

Issue

2

Publisher

Public Library of Science (PLoS)