Asian HPAI H5N1 Virus Infection Can Cause Severe Illness in People
Asian HPAI H5N1 viruses have infected the respiratory tract of humans, causing severe illness (e.g. pneumonia and respiratory failure) and death in some people.
The majority of human infections with Asian HPAI H5N1 have occurred among children and adults younger than 40 years old. Mortality has been highest in people aged 10-19 years old and in young adults. Most human Asian HPAI H5N1 cases have presented for medical care late in their illness and have been hospitalized with severe respiratory disease. However, some clinically mild cases have been reported, especially in children.
Of the few avian influenza A viruses that have crossed the species barrier to infect humans, Asian HPAI H5N1 virus has caused the largest number of detected cases of severe disease and death in humans. However, it is possible that the most severely ill people are more likely to be diagnosed and reported, while milder cases are less likely to be detected and reported. Despite the high mortality, human cases of Asian HPAI H5N1 remain rare to date, even among persons exposed to infected poultry.