Influenza b

Influenza B is a contagious viral respiratory infection caused by the type B virus, one of the two influenza virus types that drive seasonal epidemics. It occurs worldwide and affects all age groups, with a higher risk of severe illness in pregnant women, young children, older people and those with chronic medical or immunosuppressive conditions. It spreads through droplets when an infected person coughs or sneezes, and through contaminated hands, especially in crowded settings such as schools. Symptoms begin suddenly with fever, dry cough, sore throat, headache, muscle pain and exhaustion; severe cases can lead to pneumonia and sepsis. Most cases are diagnosed clinically, while nose or throat swabs tested by rapid or laboratory methods confirm the virus. Care is mainly supportive, with rest, fluids and simple pain relief; antibiotics do not work against viral infections, whereas antiviral medicines are advised for people at high risk or with severe illness.

Seek urgent care for a high fever with a stiff neck, rash, confusion, difficulty breathing, or fever after travel to a malaria area. See a doctor when a fever lasts more than three days, when symptoms return after treatment, or when you may have been exposed to an infection that needs testing. Call the local emergency number for any symptom that is sudden and severe. This page is a reference for healthcare professionals and does not replace an assessment.