Does the flu shot make you sick and do you need it every year? California doctors answer
The flu vaccine has been around for nearly a century, and still, the misconceptions and conspiracies surrounding it cause hesitation.
One thing remains true: Influenza, also known as the flu, can cause severe illness.
According to the U.S. Centers for Disease Control and Prevention, flu activity typically peaks between December and February, so California health officials are urging people 6 months and older to get vaccinated now. In a November statement, the California Department of Public Health said it’s the “best way to protect yourself and your family.”
Roughly 4,600 Californians died from the flu or pneumonia, which can be a complication, in 2021, according to CDC data.
That’s a more than 1,400 decrease from one year prior.
“These viruses don’t care that we are tired, they don’t care that we are tired of getting stuck with needles,” said family medicine specialist Dr. Kristin Gates with Kaiser Permanente South Sacramento.
“I think the key thing is just realizing illnesses won’t make an exception for us so you just want to make sure that you’re making your decisions with that understanding.”
The following responses were edited for brevity and clarity. The Sacramento Bee posed the same questions to three Northern California doctors in phone interviews.
Our experts include:
Dr. Kristin Gates, family medicine specialist at Kaiser Permanente South Sacramento
Dr. Peter Chin-Hong, doctor and professor at the University of California, San Francisco, specializing in infectious diseases
Dr. Dean Blumberg with UC Davis Health, chief of pediatric infectious disease
Here’s what the doctors said:
1. The flu vaccine makes you sick
Completely false: The flu vaccine cannot make you sick but you could be infected with a different virus around the time of your vaccination.
Gates: It doesn’t make you sick, but people aren’t crazy in thinking, ‘when I got the flu shot, I feel like I got sick right after.’ It makes it easy for another virus to knock on the door and not have as much resistance because your immune system is distracted.
Chin-Hong: No, the flu vaccine doesn’t make you sick. A lot of things are going around at the same time when people are getting these shots usually. The second thing is, you can get local reactions to the vaccine because your immune cells are training.
Blumberg: All medications, all vaccines can have side effects. This generally lasts a day or two and then it goes away but it does not cause the flu. There‘s no way that the injected flu vaccine can cause the flu because there’s no live virus in there.
2. Flu vaccine symptoms are contagious
Completely false: Flu vaccine symptoms are not contagious because the virus in the vaccine is not infectious.
Gates: It all depends on what’s causing the symptoms. If the symptoms were caused by the vaccination, you wouldn’t be able to spread.
Chin-Hong: No, flu vaccine symptoms are not contagious because nothing is live that’s causing the symptoms. You can’t transmit something that’s not alive.
Blumberg: There’s no way that they can be contagious because it’s not an infection. It’s not a live virus, it’s completely inactivated.
3. You can catch the flu from the flu vaccine
Completely false: The flu injection is made from an inactive flu virus and the nasal spray is created from live, weakened influenza viruses. Neither causes the flu.
Gates: If you got the shot, it’s a killed virus. You cannot get the flu from the vaccine itself.”
Chin-Hong: You can’t catch the flu from the flu vaccine. The most common flu vaccine is not live, so you can’t catch the flu from it. The flu mist is so weak that you can’t really get flu from it.
Blumberg: That just can’t happen. The nasal spray vaccine, which is not widely available, that’s an attenuated form of influenza virus. You can get an extremely mild case of influenza but certainly not anything like getting influenza itself.
4. You don’t need the flu vaccine every year
Completely false: The flu virus is constantly changing and your protection from the annual vaccination weakens over time.
Gates: Your immune system’s awareness of what the flu was last year doesn’t give it any protection for this year because it changes. Also, the immunity doesn’t last indefinitely.
Chin-Hong: You need a flu vaccine every year because there are different kinds of flu that circulate and you want to match the type of vaccine you get to one that experts have predicted would circulate in the same time.
Blumberg: Even if you had the flu vaccine last year, you still need to get one this year for protection for this year. In addition to that, the strains of influenza that are circulating change slightly every year. The vaccine changes to match up better with them.
5. Getting the flu shot in the winter protects you from the virus longer
Misunderstood: The general advice is to get vaccinated in the fall season ahead of peak flu activity in the winter months.
Gates: You want to be protected before you’re at the greatest risk of exposure. Really why you’re trying to get it early is because you just can’t predict when the peak is going to be.
Chin-Hong: You want to have the antibodies that you develop after getting the vaccine peak at the time when flu is circulating. You want to get it anytime before Thanksgiving, but because the flu season can last longer, getting it at any time is going to be so beneficial.
Blumberg: You normally get about four to six months of protection from influenza vaccine, so that’s why it’s recommended to get it sometime around the fall so it can protect you through about April or so. It’s impossible to time it perfectly.
6. I don’t need the flu vaccine because I’ve had the flu before
Misunderstood: Your chances of contracting influenza or your symptoms being severe are greater when you’re not vaccinated.
Gates: Yes, you are protected if the same version was going to be the only version of the virus that you were going to be exposed to. But because it changes, you end up being vulnerable to another infection.
Chin-Hong: If you’ve gotten the flu before, there are lots of different kinds of flu. Being protected against one type doesn’t mean you have protection against the other types.
Blumberg: If you got the flu last year, then you’re still going to be susceptible this year. Even if you get infected with one of the strains this year, there’s still two more stains out there that can get you.
7. I don’t need the flu vaccine because I’ve never had the flu
Completely false: The annual flu shot protects you from influenza.
Gates: What helps the most is that everyone is protected so that there’s minimal flu that’s going around.
Chin-Hong: Never having had the flu doesn’t mean that you’re protected against getting the flu in the future. Every year there’s differences in what circulates and you want to be as prepared as possible.
Blumberg: Even if you’ve never had the flu, you’re still at risk every year for getting influenza and you never know what contact is going to lead to that infection.
8. Contracting the flu builds my immune system more than the vaccine
Misunderstood: The flu vaccine is the safest way to protect yourself and those around you from influenza.
Gates: A lot of times, we don’t see ourselves in relationship to the people who are around us. If it was something where it was only going to impact us, I think there’s a little bit more room to have that level of thought. But the risks are too great and the impact on the larger community is too great.
Chin-Hong: Contracting the flu certainly can give you antibodies, but it can also make you really, really sick. It can kill you, particularly in the very young and very old.
Blumberg: If you get the flu, you do get immunity to that strain of influenza. But then you have to suffer through getting the flu. The vaccine is going to have less symptoms than getting an actual infection.
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