If you've ever been curious about how flu vaccinations make their way to your local clinic or doctor's office, we have briefly highlighted the primary steps that are involved. Each year, this same process is followed; read on to learn more.
WHO Selects Top Virulent Strains -
Since influenza is a virus, it mutates every single year. The World Health Organization's Global Influenza Surveillance Network selects the top three strains every year, usually during the fall months. These strains serve as the basis for that year's flu vaccine. The three strains that are chosen represent the most troublesome strains and are the ones that give the WHO the most concern.
Eggs' Roles In Developing The Flu Vaccine -
Once the three virus strains are chosen, scientists get to work on developing the flu vaccine in earnest. They use fertilized chicken eggs to do this. It's a simple process, really: a chicken egg is cracked and one of the three viruses is injected inside. Once the embryo becomes infected, the virus is harvested and purified two days later. The same thing is done for all three strains of the virus.
Viral Fragments Combined -
Fragments from all three virus strains that have been harvested from the eggs are collected and combined. Incredibly, one egg is required for every dose of the influenza vaccine, meaning that millions and millions of eggs are used every single year. At least all of those eggs are going to a good cause - keeping people healthy and free from the influenza virus.
Final Preparations Are Made -
Over the winter, the vaccine is tested rigorously to ensure its safety and its effectiveness. Time is of the essence during this period, since new flu viruses are being mutated all the time. Even as the vaccine is being readied, new strains are emerging. That is why the cycle never ends and is repeated each and every year. Generally, the vaccine is ready to be manufactured by August.
The Flu Vaccine Goes Public -
In September, the new flu vaccine for the year is shipped out all around the world. From Australia to North America to Europe, Asia and Africa, millions upon millions of doses are delivered. Once that is complete, vaccinations begin in earnest getting the vaccine as soon as possible is important; it takes ten to fifteen days to take effect, and flu season is usually from May to early October.