Situation at a Glance

On 16 January 2024, Brazil notified the World Health Organization (WHO) of a laboratory-confirmed human infection with swine-origin influenza A(H1N1) variant (v) virus, in the municipality of Toledo, State of Paraná. The patient, who had underlying medical conditions, developed symptoms and was hospitalized on 16 December 2023. He had no history of exposure to pigs and has fully recovered. From the epidemiological investigation, no close contacts were identified. This is the first human infection caused by an influenza A(H1N1)v virus reported in Brazil in 2024, and the ninth case of a human infection with a swine variant virus reported in the state of Paraná, Brazil, since 2015. According to the International Health Regulations (IHR) 2005, a human infection caused by a novel influenza A virus subtype is an event that has the potential for high public health impact and must be notified to the WHO. Based on the information currently available, WHO considers this a sporadic case. The likelihood of community-level spread among humans and/or international disease spread through humans is considered low. 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.