News Rendezvous

On 25 November 2023, the International Health Regulations National Focal Point (IHR NFP) of the United Kingdom of Great Britain and Northern Ireland (United Kingdom) notified the World Health Organization (WHO) of a human case of swine-origin influenza A(H1N2) virus infection.

This is the first swine influenza A(H1N2)v case reported in the United Kingdom. Human infections with swine-origin influenza viruses have been sporadically detected in the past in countries in the Americas, Asia, Australia and Europe.

When a human is infected with a swine-origin influenza virus, the virus is referred to as a variant (or “v”) virus. Most human cases result from exposure to swine influenza viruses through direct contact with infected swine or contaminated environments. Current evidence suggests that these swine-origin influenza viruses have limited ability for sustained transmission among humans.

This case was identified as part of routine surveillance of respiratory illnesses. The source of infection for this case is under investigation and contact tracing is in process. To date, no other confirmed cases associated with this event have been reported.

WHO is in communication with national authorities to monitor the situation closely. Ongoing investigations are in place to identify the source of the infection and to characterize the risks of this influenza variant virus.

WHO assesses the risk of spread of swine-origin influenza viruses through humans and/or community-level spread among humans as low. However, because these viruses continue to be detected in swine populations worldwide, further human cases following direct or indirect contact with infected swine can be expected.

Current evidence suggests that these viruses have not acquired the ability to sustain transmission among humans. Due to the constantly evolving nature of influenza viruses,

WHO continues to stress the importance of global surveillance to detect virological, epidemiological and clinical changes associated with circulating influenza viruses that may affect human (or animal) health and timely virus sharing for risk assessment.