The risk of acquiring avian influenza from commercial poultry products and hen eggs: A qualitative assessment

Abstract

High pathogenicity and low pathogenicity avian influenza (HPAI and LPAI) viruses primarily infect birds, but they can also cause illness in other species, including humans. Some avian influenza (AI) strains can cause fatality rates of over 50 % in human infections. In October 2021, there was a substantial increase in the number of AI infections reported in birds in the UK. Given concerns that more infected and/or contaminated poultry products might reach retail, a risk assessment was performed to ensure that advice relating to the handling and consumption of these products remained appropriate.

The products considered in this risk assessment were commercial chicken and turkey products, farmed duck and geese products, and table eggs. The risk pathway included the likelihood animals or eggs from an infected flock would be sent for further processing, whether the resulting products would be released to retail after inspection, viral persistence during distribution and storage, and the ability of AI viruses to infect humans via the gastrointestinal route. The risk from any AI virus, not just the A(H5N1) strain that began circulating in 2021, was considered. Data was obtained from literature searches and FSA surveys.

The risk assessment determined that the likelihood of human infection with AI from poultry products for the UK population from handling and consuming commercial chicken or turkey products was negligible with low uncertainty, and for farmed duck and geese products was very low with medium uncertainty. The likelihood of infection for people in the UK from handling and consuming hen table eggs was very low with low uncertainty. The uncertainty rankings relate to the differing amounts of data available for each group of poultry products. The severity of illness in humans from AI infection was considered high with medium uncertainty. The conclusions of this risk assessment for UK consumers largely reflected advice and assessments from other countries and previous UK assessments. Given this, current guidance for handling and consuming poultry products was considered appropriate despite the increase in infections in birds during the 2021/22 and 2022/23 avian flu seasons. Since AI viruses were considered generally, these risk characterisations may need to be revisited based on evidence specific to a circulating virus to support risk management decisions.