Outbreak Action Guide
What to do — before, during and after exposure
Plain-language guidance drawn from CDC and WHO, organized into Prevention, Possible exposure, and Symptoms or illness. Educational only — not a diagnosis.
COVID-19
COVID-19 is a respiratory illness caused by the SARS-CoV-2 virus. Most people have mild illness, but it can be severe, especially for older adults and people with certain health conditions.
Action guide · What Should I Do? →
Seasonal influenza
Flu is a contagious respiratory illness caused by influenza viruses. It can cause mild to severe illness and sometimes leads to hospitalization or death, especially in young children, older adults and people with certain conditions.
Action guide · What Should I Do? →
Avian influenza (H5N1)
H5N1 bird flu mainly infects wild birds and poultry and has also spread among some mammals, including U.S. dairy cattle. Human infections are rare and have mostly followed close contact with infected animals. No sustained person-to-person spread has been identified, and CDC rates the risk to the general public as low.
Action guide · What Should I Do? →
Measles
Measles is one of the most contagious diseases in the world. It can cause pneumonia, brain swelling (encephalitis) and death, especially in young children. The MMR vaccine is very effective at preventing it.
Action guide · What Should I Do? →
Mpox
Mpox is a viral illness that causes a painful rash and sometimes fever and swollen lymph nodes. There are two main types (clade I and clade II). Most people recover in 2–4 weeks, but it can be severe for some.
Action guide · What Should I Do? →
RSV
RSV is a common respiratory virus that usually causes mild, cold-like symptoms. It can be serious for infants and older adults; before RSV immunizations became available, it was the leading cause of hospitalization in U.S. babies.
Action guide · What Should I Do? →
Dengue
Dengue is a viral infection spread by mosquitoes, common in tropical and subtropical regions. About 1 in 4 infections causes illness. Most people recover in about a week, but dengue can become severe and life-threatening.
Action guide · What Should I Do? →
Other & emerging diseases
Other outbreaks reported by WHO and national public-health authorities (for example Ebola, Marburg, cholera, Nipah, MERS).
Official outbreak reports →