Serological evidence of human infections with highly pathogenic avian influenza A(H5N1) virus: a systematic review and meta-analysis

Chen, X. and Wang, W. and Wang, Y. and Lai, S. and Yang, J. and Cowling, B. J. and Horby, P. W. and Uyeki, T. M. and Yu, H.

BMC Med (2020) 18: 377

DOI: 10.1186/s12916-020-01836-y

Abstract

BACKGROUND: Highly pathogenic avian influenza A(H5N1) virus poses a global public health threat given severe and fatal zoonotic infections since 1997 and ongoing A(H5N1) virus circulation among poultry in several countries. A comprehensive assessment of the seroprevalence of A(H5N1) virus antibodies remains a gap and limits understanding of the true risk of A(H5N1) virus infection. METHODS: We conducted a systematic review and meta-analysis of published serosurveys to assess the risk of subclinical and clinically mild A(H5N1) virus infections. We assessed A(H5N1) virus antibody titers and changes in titers among populations with variable exposures to different A(H5N1) viruses. RESULTS: Across studies using the World Health Organization-recommended seropositive definition, the point estimates of the seroprevalence of A(H5N1) virus-specific antibodies were higher in poultry-exposed populations (range 0-0.6%) and persons exposed to both human A(H5N1) cases and infected birds (range 0.4-1.8%) than in close contacts of A(H5N1) cases or the general population (none to very low frequencies). Seroprevalence was higher in persons exposed to A(H5N1) clade 0 virus (1.9%, range 0.7-3.2%) than in participants exposed to other clades of A(H5N1) virus (range 0-0.5%) (p \textless 0.05). Seroprevalence was higher in poultry-exposed populations (range 0-1.9%) if such studies utilized antigenically similar A(H5N1) virus antigens in assays to A(H5N1) viruses circulating among poultry. CONCLUSIONS: These low seroprevalences suggest that subclinical and clinically mild human A(H5N1) virus infections are uncommon. Standardized serological survey and laboratory methods are needed to fully understand the extent and risk of human A(H5N1) virus infections.

Citation

Chen, X., Wang, W., Wang, Y., Lai, S., Yang, J., Cowling, B. J., Horby, P. W., Uyeki, T. M., & Yu, H. (2020). Serological evidence of human infections with highly pathogenic avian influenza A(H5N1) virus: a systematic review and meta-analysis. BMC Med, 18(1), 377. https://doi.org/10.1186/s12916-020-01836-y Animals, Humans, Seroepidemiologic Studies, Birds, *Influenza A(H5N1), *Influenza in humans, *Serological evidence, Influenza A Virus, H5N1 Subtype/*pathogenicity, Zoonoses/*epidemiology, Influenza in Birds/*epidemiology, Influenza, Human/*epidemiology, none of this research funding is related to avian influenza, Pharmaceutical Company, S.L., J.Y., B.J.C., P.W.H., and T.M.U. declare no competing interests., viruses. BJC has received honoraria from Roche and Sanofi Pasteur. X.C., W.W., Y.W.,

Keywords

• Animals
• Humans
• Seroepidemiologic Studies
• Birds
• *Influenza A(H5N1)
• *Influenza in humans
• *Serological evidence
• Influenza A Virus
• H5N1 Subtype/*pathogenicity
• Zoonoses/*epidemiology
• Influenza in Birds/*epidemiology
• Influenza
• Human/*epidemiology
• none of this research funding is related to avian influenza
• Pharmaceutical Company
• S.L.
• J.Y.
• B.J.C.
• P.W.H.
• and T.M.U. declare no competing interests.
• viruses. BJC has received honoraria from Roche and Sanofi Pasteur. X.C.
• W.W.
• Y.W.,