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The History of the Flu Shot and Some Common Misconceptions

Mar 21st, 2018 | By: Grace Donnelly , fortune.com

Nearly 6% of all Americans seeking medical care now have flu symptoms and at least 22 children have been killed by the influenza virus so far this year. The flu kills about 12,000 Americans in a mild year and up to 56,000 in particularly severe years, according to estimates from the Centers for Disease Control.

But in the 13 years that the CDC has used its current flu-tracking system, this is the first season that flu activity has been so widespread across the entire U.S., according to Dan Jernigan, director of the influenza division at the national Center for Immunization and Respiratory Diseases.

“Flu is everywhere in the U.S. right now,” Jernigan said, “This is the first year we have had the entire continental U.S. be the same color on the graph, meaning there is widespread activity in all of the continental U.S. at this point.”

The state of Alabama declared a public health emergency due to the size of the outbreak there and 34 people in San Francisco died from flu-related causes during the last week of 2017.

Experts have said we may be at peak volume for flu cases, but it’s not too late to get a flu shot.

Although the flu vaccine varies in effectiveness from year to year and works best when administered in the fall before the season ramps up, flu shots can still save lives even when they don’t prevent people from contracting the virus. Here’s why it’s important that everyone take advantage of this modern medicine during flu season.

How was the flu vaccine created?

Scientists had a working flu vaccine by the 1940s, after the influenza virus was first discovered in the early 1930s.

Soldiers fighting in World War II were the first patients to receive the flu vaccine when it was approved for military use in 1945 and civilian use was approved the following year.

Thomas Francis Jr., MD, and Jonas Salk, MD, who are more famously known for developing a vaccine for polio, were both integral to developing the flu vaccine.The earliest flu shots protected against a single strain of the disease, influenza A. In 1942, after the discovery of influenza B, a bivalent vaccine, which protected against influenza A and influenza B, was produced. As scientists learned more about the virus and the ways it mutates, the World Health Organization (WHO) developed a more rigorous process for targeting the strains that affect the most people which was instituted in 1973.

How effective are flu shots?

Today, flu shots contain three strains of the virus. The WHO determines which strains to include based on how the virus has mutated over the past year and where it is spreading. The trivalent vaccine combines two strains of the influenza A virus and one strain of influenza B in order to prompt your immune system to develop antibodies for all three versions of the flu.

It takes about two weeks after you get a flu shot for your body to build immunity.

But it’s still a guessing game. There are four species of the flu virus — A, B, C, and D — with the most common being strains of A or B viruses. Most years the flu shots produced are between 40% and 60% effective.

The holy grail is to target a piece of the virus by antibody or t cell,” Tom Evans, the CEO of a company called Vaccitech that is working on a universal vaccine they hope can be used to treat all strains of influenza A, told National Geographic.

Typically two A strains are the most common during peak flu season: H1N1 and H3N2. This year, the H3N2 strain is particularly nasty and prevalent — more than 80% of all cases this season involve this type of flu virus, according to CDC data.

“H3N2 is a bad virus,” Jernigan, the CDC official, said. “We hate H3N2.”

To make matters worse, the 2017 vaccine doesn’t combat this more severe strain of H3N2 very well. It’s still too soon to know for sure, but public health experts predict the current flu shot will only have 10% to 30% efficacy.

What is the flu vaccine made of?

The flu vaccine contains a cocktail of three or four strands of either the inactivated influenza virus or particles designed to look like those viruses to your immune system. Early versions of the flu shot were not as purified as modern vaccines which sometimes contributed to side effects like fever, aches, and fatigue.

This likely led to the misconception that you can contract the flu from the flu shot, but that simply isn’t true. Some people do still experience side effects like headache, fever, and nausea after getting vaccinated, but it’s not possible to contract the influenza virus from the shot, according to the CDC.

Another common concern is that flu shots contain mercury. The flu vaccine does contain a preservative called thimerosal, which breaks down to ethylmercury once inside the body. However this is not the form of the element that causes mercury toxicity. That, in case you’re wondering, is methylmercury.