Swine Flu Symptoms - Swine Flu (H1N1)

Swine flu is a respiratory infection. The CDC recommends that swine influenza be considered in people who have fever and respiratory symptoms, especially cough or a sore throat. Ill people may also have fatigue, chills, headache, or body aches. Nausea, vomiting, or diarrhea has also occurred in people with swine flu.

Children and young adults (ages 0-24 years) have the highest rate of infection. Older adults (>65 years) are less likely to have infections, leading some to speculate that older individuals might have "partial immunity." Partial immunity occurs when people make antibodies against one virus that have some effect on another virus. Thus, older people who were exposed to a similar virus may be partly protected against swine flu. The key words here are may and partly. There is no guarantee that an older person is protected, and if they do get infected, they are at risk for complications requiring hospitalization.

Although the infection is usually mild, some people with swine flu have experienced serious respiratory illness, including pneumonia or respiratory failure leading to death. Pregnant women are at high risk for severe disease. Of concern, most deaths have occurred in adults under age 65, including people under age 25. This is the opposite of what happens in a normal influenza season, when most deaths occur in the elderly.

People with chronic medical conditions are always at higher risk for complications from influenza and this is also true of swine flu. These chronic medical conditions include asthma, chronic lung disease, heart disease, diabetes, suppressed immune systems (including from chemotherapy), and kidney failure.

People with swine influenza are assumed to be contagious from one day before getting sick until 24 hours after symptoms resolve. Children and people with weak immune systems may be infectious for longer periods (for example, 10 days).