Every year, we see those signs pop up reminding us to get our yearly flu shot. If you have ever wondered how they make each year’s shot, read on.
In 1938, the first flu vaccine was created by Jonas Salk and Thomas Francis, and was used to protect soldiers who fought in World War II. Vaccines were improved from the 1940s to the 1960s, but still were not as purified as vaccines are today. Side effects of fever and aches were common, and were blamed on the flu shot.
However, the flu shot has always been made from non-live virus, so flu shots cannot give you the flu. The side effects some have to the flu shot are from one’s own body building an immune response.
Flu nasal spray like FluMist is made from weakened virus so is only recommended for those without health problems, those aged 2 to 49 years old, and those who meet other restrictions.
Prior to 2009, there had not been a widespread outbreak of swine flu in humans. The outbreak started in Mexico and by June, had spread to 74 countries.
“On Oct. 25, 2009, President Obama declared a national emergency as a result of the outbreak,” which had reached 46 states in the United States, reported Emedicinehealth.com.
A new vaccine against the H1N1 virus was quickly made. The swine influenza virus H1N1 was named based on the two main proteins in the flu virus hemagglutinin and neuraminidase.
A second strain called H3N2v needed to be added to the swine flu vaccine due a mutation of the virus. Each year, there are only a few flu virus strains that circulate, but viruses can continue to mutate through alterations in the eight RNA strands that make up the influenza virus genome.
The yearly seasonal flu shot is made up from strains that currently have been circulating worldwide. Labs from 142 National Influenza Centers in 113 countries study influenza disease trends and send influenza viruses to five World Health Organization Collaborating Centers for Reference and Research on Influenza.