Is the Flu Shot Effective? Here’s What Science Says

The flu shot is our greatest weapon against influenza. It’s something we do to protect not only ourselves but those around us. Getting vaccinated is especially necessary for those with a high risk of developing severe complications, like young kids, pregnant women, people over 65, and those with underlying health issues. 

The flu is not the same as a cold, and it can be a severe illness. Some people experience mild symptoms and recover after several days. But others fight for their lives in the hospital due to life-threatening complications that can lead to death. Getting the vaccine is your best bet in fighting the flu and also protecting the people around you. 

How Effective is the Flu Shot?

Two weeks after vaccination, your system produces antibodies, helping the immune system recognize and fight influenza viruses. According to the CDC, a flu shot lessens the risk of infection by around 40% to 60%. You might be thinking, “What’s the point of getting the seasonal flu vaccine if it’s not 100% effective?” Not only are you less likely to get sick, but if you do, your symptoms will be less severe and shorter in time.

So, is the flu shot effective? Absolutely.

Factors that Affect the Flu Vaccine’s Effectiveness

The health status of the vaccine recipient and how well the vaccine matches circulating flu viruses contribute to the flu shot’s effectiveness. Every year, the CDC works to find out which types of flu viruses are going around. Then, depending on the data gathered, they predict which ones are most likely to circulate the following year. 

A mismatch between the most common circulating strains and the vaccines may result in lower effectiveness against infection. However, it’s still crucial to get the vaccine, especially for those considered high-risk for infection. This is because it still offers some protection against the other circulating viruses and lowers the chances of falling ill.

doctor preparing flu shot

Why Should You Get the Flu Vaccine Every Year?

The vaccine that protected you last year may not work for the strains that are circulating this season. New vaccines are released annually to keep up with the constantly evolving, mutating, and adapting influenza viruses. So, even if you are completely healthy, a yearly flu vaccine can provide you with continuous protection from illness. 

Children, elderly people, pregnant women, and other people in the higher risk groups are most likely to develop severe complications from flu. Whether you are among these vulnerable groups or you live with someone who is, getting vaccinated is crucial! 

The Benefits of the Flu Vaccine

We’ve already touched on some of these, but let’s dive deeper.

1. The flu vaccine prevents infection and reduces hospitalization rates in people who get sick despite receiving the vaccine.

From 2019 to 2020, flu vaccination in the US prevented roughly 7.5 million flu infections and millions of influenza-associated medical visits, hospitalizations, and deaths. Another study from 2021 connected flu shots with a 31% lower risk of death and 26% lower risk of ICU admission. Despite not being 100% effective, the flu vaccine has helped millions survive the flu season. 

2. The seasonal flu vaccine reduces hospitalizations for those suffering from chronic health conditions.

The vaccine was linked with fewer hospitalizations in two separate studies involving chronic lung disease and diabetes patients who had gotten the vaccine. Furthermore, based on new research, heart failure patients vaccinated in any given year are 50% less likely to die during the flu season. There was also a 20% decrease in the risk of death for the rest of the year. The flu shot is undeniably a massive lifesaver for those suffering from chronic illnesses. 

3. The flu vaccine helps protect pregnant women. 

The World Health Organization (WHO) recommends flu vaccination for all pregnant women worldwide for a good reason. Getting the flu shot during pregnancy is completely safe and may lessen the chances of severe infection by 40%. Immunization is all the more essential for pregnant women with underlying health issues like asthma and diabetes. 

4. Flu vaccines can save children.

In 2017, the CDC published a study showing that flu shots can significantly decrease a child’s risk of dying from influenza. The research, citing data from 2010 and 2014, showed that flu vaccines reduced death by 65% among healthy children and 51% among those with underlying medical conditions. 

Since their immune systems are still developing, kids have a higher chance of acquiring flu viruses and experiencing complications. Flu shots, therefore, help their vulnerable immune systems fight invading viruses.

mom taking daughter's temperature

5. Flu vaccines help the elderly strengthen their immune defenses.

As we get older, our immune responses weaken, making us more vulnerable to illnesses. This means that adults 65 years and older have an increased risk of severe influenza complications compared to younger people. 

The CDC estimates that around 50% to 60% of hospitalizations related to flu transpired among adults in this age group in recent years. In addition, 70% to 85% of flu-associated deaths involved elders 65 years and older. However, seniors who got the flu vaccine lessened their risks of hospitalization by up to 43%, proving that vaccination indeed saves lives, even for people with weaker immune systems. 

Who Can Get the Flu Vaccine?

People as young as six months should get the flu shot every year. (Be sure to read my blog on childhood vaccines!) There are different kinds of flu vaccines. Some are only appropriate for people 65 and older, while others are best for younger adults. All of these vaccines are safe, but just like any other vaccine, they may cause mild side effects that typically go away on their own within a few days. Severe reactions, however, are rare and usually occur hours after getting the shot. 

If you’re concerned that you (or your child) shouldn’t get the vaccine, speak to your doctor first.

The Flu Shot Save Lives

Influenza is an infectious respiratory illness that affects millions of people in the US each year. The 2019-2020 flu season alone saw about 35 million flu-related infections and millions more flu-associated hospitalizations and deaths. Yet, despite the many benefits of the seasonal flu vaccine, only around half of Americans get the vaccine annually. According to the CDC, merely 51.8% of people in the U.S. received the vaccine in 2019 and 2020. 

Protecting ourselves from influenza is more important than ever, especially amid the pandemic.

Want to keep reading? Head to my blog on vaccine myths next.

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Author: Jonathan Baktari MD

CEO of e7health and US Drug Test Centers

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Jonathan Baktari MD

Jonathan Baktari, MD brings over 20 years of clinical, administrative and entrepreneurial experience to lead the current e7 Health team. He has been a triple board-certified physician with specialties in internal medicine, pulmonary and critical care medicine. He has been the Medical Director of The Valley Health Systems, Anthem Blue Cross Blue Shield, Culinary Health Fund and currently is the CEO of two healthcare companies.
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