The U.S. Food and Drug Administration (FDA) has approved H1N1 flu vaccines from four manufacturers. The vaccines, which are identical, should be available at clinics around the country by mid October, according to the agency. An FDA press release reported that “the 2009 H1N1 vaccines induce a robust immune response in most healthy adults eight to 10 days after a single dose.”
The U.S. Center’s for Disease Control (CDC) has encouraged people to get their seasonal flu vaccines as soon as possible, although it is possible to get both the H1N1 and seasonal vaccines at the same time. Possible side effects from both types of flu vaccine are similar, and include: soreness at the injection site, mild fever, body aches, and fatigue. For nasal spray versions of the vaccine, possible side effects include runny nose or nasal congestion, sore throats in adults, and — in children 2 to 6 years old — fever.
According to the FDA release: “As with the seasonal influenza vaccines, the 2009 H1N1 vaccines are being produced in formulations that contain thimerosal, a mercury-containing preservative, and in formulations that do not contain thimerosal. People with severe or life-threatening allergies to chicken eggs, or to any other substance in the vaccine, should not be vaccinated.”