We are underestimating, again, the true burden of H5N1 in humans

• Published in: BMJ global health Vol. 8; no. 8; p. e013146
• Main Authors: Gomaa, Mokhtar, Moatasim, Yassmin, El Taweel, Ahmed, Mahmoud, Sara H, El Rifay, Amira S, Kandeil, Ahmed, McKenzie, Pamela P, Webby, Richard J, El-Shesheny, Rabeh, Ali, Mohamed Ahmed, Kayali, Ghazi
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group LTD 01.08.2023; BMJ Publishing Group
• Subjects: Antibodies; Avian flu; Bird migration; Ethics; Field study; Infections; Meta-analysis; Pathogens; Poultry; Serology; Viruses; United States > US; Egypt
• ISSN: 2059-7908; 2059-7908
• DOI: 10.1136/bmjgh-2023-013146

Correspondence to Dr Ghazi Kayali; ghazi@human-link.org Summary box From mid-2021, a dramatic increase in activity and geographical distribution of clade 2.3.4.4b H5N1 viruses in animals occurred. Similar to the situation in Egypt, a meta-analysis concluded that 2% of humans exposed to sick or dead poultry were expected to be infected.11 Similarly, a meta-analysis conducted on Chinese H5 seroprevalence studies concluded that the seroprevalence may reach 3.2% in poultry-exposed populations.12 The true burden of H5 infection in humans has been underestimated as global surveillance systems tend to detect only severe cases that require hospitalisation and miss asymptomatic, mild or moderate cases.3 The extent of clade 2.3.4.4b human infections is unknown, but almost certainly more than the reported number, especially as this virus has shown an ability to infect several non-human mammals on a large scale. The well-recognised limitations of our global zoonotic disease surveillance systems highlight the importance of supplementing data generated from such surveillance systems by data from field research studies at the human-animal-environment interfaces including seroprevalence studies. Ethics approval This study was approved by the Institutional Review Board of St. Jude Children’s Research Hospital, USA and by the Ethics Committee of the National Research Centre, Egypt.