Flu Vaccine – The Educated Guess

If you have ever wondered how the flu vaccine is made, or better yet, determined as to what strain it will need to fight, here’s the scoop. From what I’ve uncovered, scientists consider it as difficult as finding a needle in a haystack. These intense professionals spend countless hours and months closely observing and tracking flu patterns from all over the world and plug information into models to ultimately make an educated guess on how to develop the upcoming year’s vaccine. It’s never the same either. From year to year, everything must start from the beginning. 

According to the experts, the flu is constantly changing, mutating in ways that give it the ability to push past our body’s immune defenses, even if we’ve had the flu virus before or have received the vaccine. They refer to it as much like predicting the weather as it changes by the minute and makes forecasting seem like playing with pure luck. Scientists begin their process in February of each year for the approaching flu season, which generally begins in the fall. The World Health Organization (WHO) hosts a meeting where these brilliant minds can gather together and discuss the current and previous strains discovered and then cohesively make a decision on which strain to combat.

In the US, our division of the World Health Organization is run out of the CDC (Centers for Disease Control and Prevention) in Atlanta, Georgia. This team performs year-round genetic sequencing to determine how the flu is “behaving” as well as whether or not it’s showing resistance to the antiviral drug developed to treat it. As the testing and analyzing advances, lead microbiologists in the CDC’s genomics team will dissect 7,000 specimens sent from sick patients. From there, the process heads north to Swiftwater, Pennsylvania where the Sanofi Pasteur plant will begin manufacturing the vaccine. 

In the Sanofi pharmaceutical plant, 1 million chicken eggs are prepared to be injected with the virus the WHO experts have determined will be the most likely strain of flu to attack us in the upcoming season. The eggs are left to incubate for a few days and then the virus is extracted and “inactivated” for use in the development of the flu vaccine. Those 1 million eggs make up the 1 million doses of the vaccine to be shipped out to medical practices and drugstores all over the country by August of that year. 

Of course, there are several other factors in the development of the vaccine, such as adjusting the formula to work differently in older patients since they are more susceptible due to weakened immune systems naturally occurring with age. The flu shot is said to be roughly 50% effective although that number can rise or fall in any given year. In those lower cases, it’s the result of a vaccine formula that just didn’t get predicted well enough to match the strain going around. Again, this is like forecasting the weather, it can change at any given moment. 

As the flu continues to change, scientists continue to stay committed to finding the right potion. Studies advance and evolve with the changes and in the long-run, regardless of the chance it might not be the perfect blend, get your flu shot. The chances are in your favor and let’s be honest, no one wants the flu. Here’s to you! May you have a happy and healthy new year!  

~Shannon Hadeed

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