Influenza 2009 H1N1

Type: Viral

Geography: Worldwide

Cases Per Year: 491,432

Fatality Rate: <1%

First Discovered: 2009 in Veracruz, Mexico

In the spring of 2009, a novel influenza A (H1N1) virus emerged. The pandemic lasted for about 19 months. Despite being called a “swine flu”, the H1N1 virus cannot be spread by eating pork products. Similar to other influenza viruses, it is typically contracted by person to person transmission through respiratory droplets.

Symptoms usually last 4 to 6 days and include fever, cough, headache, muscle or joint pain, sore throat, chills, fatigue, and runny nose. Diarrhea, vomiting, and neurological problems have also been reported in some cases. People at higher risk of serious complications include people over 65, children younger than 5, children with neurodevelopmental conditions, pregnant women in the third trimester, and people with underlying medical conditions or weakened immune systems. In severe cases, patients generally begin to deteriorate around three to five days after symptom onset. Deterioration is rapid and many patients progress to respiratory failure within 24 hours, requiring intensive care and mechanical ventilation.

Antivirals are used to treat those with more severe symptoms or in high-risk groups. A vaccine was made available to protect people from the virus.

Photo: H1N1 – Electron micrograph.