Everyone keeps telling you to get a flu shot. There’s a good reason for it.

university of illinois immunology do I need a flu shot

Not only will it prevent or make it easier to cope with the flu, but it will also protect the people around you, especially those who cannot get vaccinated themselves for medical reasons.

If you haven’t gotten your flu shot yet, don’t worry, we’ve got you covered. On September 25th, we’re bringing you Shots4Shots, where you’ll get a flu shot and a drink shot on us! Susan R. Ross, Ph.D., Sweeney Basic Science Professor and Head, Microbiology and Immunology Department, University of Illinois at Chicago, will be there to answer all your questions about the flu shot.

We sat down with Dr. Ross before the event to learn more about the flu shot: how it’s made and why it’s so important.

Why is the flu vaccine important? The flu doesn’t seem that bad.

Although most years, coming down with the flu is not bad for most individuals, certain groups of people can die from it. This includes young children (who have no have never been exposed to the flu before), pregnant women, and adults older than 65, whose immune systems might not be as good as it once was. The flu also poses a risk to people with pre-existing conditions that make it more likely they’ll develop complications such as pneumonia. This includes people who are on immunosuppressive therapies and have chronic lung diseases and other disorders. The vaccine helps prevent people from getting infected, and even if it doesn’t, it still helps reduce the severity of their illness — maybe shortening the time frame from two weeks to a couple of days.

Why do doctors keep telling us that getting vaccines protects others? How does that work?

If people get vaccinated and don’t get the flu, they can’t pass the virus to others who aren’t vaccinated. If enough people get vaccinated, the flu can’t spread. This is called herd immunity. This happens even if the vaccine does not fully protect against the disease – if enough individuals are protected or are contagious for a shorter amount of time, the virus won’t spread. We depend on herd immunity to protect those who can’t get vaccinated for medical reasons, such as newborns.

Why is the flu vaccine so ineffective every year? 

There are several reasons why the vaccine is not always effective. First, the viral strain that spreads each year is different than the one that spread the year before, and it’s hard to select which one to put into the vaccine. The Center for Disease Control and Prevention (CDC) and the World Health Organization (WHO) select which strains of flu will go into the vaccine based on data from five international centers. These centers monitor flu outbreaks and determine which strains are most likely to spread and cause illness in the upcoming flu season.

The vaccine is made months before flu season starts so enough of the vaccine can be manufactured for everyone. Sometimes, the strain the CDC and WHO picked is not the one that spreads that season. The strains can also mutate slightly by the time they reach people, and when this happens, it’ll only be partially protective. Researchers also found that the virus used to make vaccines may change as it grows (in chicken eggs) and won’t work as well. But still, even while less effective vaccines may not completely protect someone from the flu, they can help lessen the amount of time someone is sick.

If the flu vaccine is different every year, how do we know it’s safe?

The three to four viral strains put into the flu vaccine vary from year to year, the process of how vaccines are made stays the same and this process has been proven safe. As for the viruses themselves, they generally cannot make you sick. There are two types of vaccines – one contains inactivated, or dead, viruses which cannot infect you. The other type contains live but weakened viruses, so they infect you but not strongly enough to make you sick. Doctors only give this latter vaccine to people between two and 49 years of age because infants and the elderly don’t have strong enough immune systems to handle a live virus.

How does injecting the flu virus into someone’s body protect them from getting the flu? 

When we get the flu vaccine, we make antibodies to the virus. These antibodies are like “lookouts” for your body’s defenses, your immune system. When the virus appears, these lookouts alert the immune system that a foreign invader is present, and your body kills the virus before it can make you sick. Your body also responds like this when you get the flu, but it takes much longer to mount a defense, and in the meantime, you get sick. The vaccine allows your body to make a rapid, often more effective response.

Are there any other vaccines adults should get?

The CDC recommends several vaccines for adults to protect them from tetanus, whooping cough, hepatitis, shingles, and other diseases. You can see their recommended schedule on the CDC website. Talk to your doctor to learn more.


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