H1N1 in 2009 was declared as a pandemic by WHO and there was no known vaccine till that time. However it was made available in the same year but it had limited supply. ACIP (Advisory Committee on Immunization Practices of CDC) recommended the vaccine then for people with utmost risk including pregnant women, people who live with or take care of children less than 6 years of age, healthcare and emergency medical service personnel, people up to 24 years of age and for people who are suffering from any other chronic health issues from age 25- 64.
But as supply of vaccine rose, CDC recommended it for people in age group 25-64 also as many deaths have been reported in this age group also. Since in 2009 there was a major outbreak of the virus and the same year the vaccine was identified, the vaccine itself is called “2009 vaccine”. CDC now encouraged people to get vaccinated against the virus for everybody.
The companies engaged in manufacturing these vaccines are CSL Limited, MedImmune LLC, Novartis Vaccines & Diagnostics limited and Sanofi Pasteur. All four companies use the same process to manufacture the vaccines. Like all other seasonal influenza vaccines, the 2009 H1N1 vaccines also come in formulations with or without thimerosal, which is preservative containing mercury.
The USFDA has recommended the use of one vaccine for people who are more than 10 years old and 2 vaccines with a dose separation of 4 weeks for people from 6months to 9 years. Infants beyond 6 months are too young for this vaccination program.
People having severe allergies from eggs or any other substance in the vaccine should refrain from vaccination.
Though in clinical trials, the vaccines have been well tolerated, yet there are few side effects that might occur like soreness of the injection site, mild fever, fatigue, body ache etc. If the vaccine is taken in the form of nasal spray runny nose or nasal congestion might occur for adults while for children fever is common.