You asked, we answered.
As we approach another flu season, in the middle of a pandemic, Sanford Health News answers the most common questions with help from Jeremy Cauwels, M.D., senior vice president of quality and chief medical officer for Sanford Health Plan.
1. Why do flu shots make your arm sore?
There’s a reason your arm is sore after getting a flu shot.
“You’re injecting something into a muscle and that muscle isn’t supposed to have any extra fluid in it. It’s not supposed to have anything else floating around. So, if you put a small bubble of just about anything in there, it’ll get sore. If you add that to the fact that what you’re putting in there is designed to have an immune response and whether that’s a tetanus shot or a flu shot or any other vaccination, there’s an immune response there. Those immune cells cause a little bit inflammation and caused a little bit of soreness.”
Over time, he says, the more relaxed you can get your arm before they put the needle in there, the better off you’re going to do.
“It turns out that that muscle contraction actually causes more discomfort than if you were totally relaxed. So, if you want a good tip, keep that arm good and loose.”
2. Side effects of flu shots?
Dr. Cauwels said the side effects are minimal for most people who get the flu shot.
“That being said, I’m not going to go as far as to say there are zero side effects. The vaccine contains small pieces of a virus and depending on your individual immune response, some people will feel a little bit like they got a mild case of the flu.”
The good news: there’s no live virus in there, so you won’t get the actual flu. However, if you get body aches or a little bit of muscle soreness after you’ve had a flu shot, it’s not considered to be unusual.
“I’ve heard many people say, many times: ‘I got the flu last time I got the flu shot’,” Dr. Cauwels explains. “And my response to that is ‘no, you had an immune response’, which means your immune system works and does what it’s supposed to, reacting to the things that you put in it, which is perfect.”
That doesn’t mean you shouldn’t get the flu shot anymore, he says.
“There are people that are truly allergic. There are very, very few,” Dr. Cauwels said. “For everyone else, we can find a vehicle to immunize you for the flu.”
3. When are flu shots available?
“They became available the middle of September and they will continue to be available throughout the winter season.”
The important part to remember about the flu shot though is, because it’s not like a vaccine for chicken pox or measles or mumps rubella, some of the things that we give kids is the duration of the flu shot is variable in people as to how long it’s effective. That’s the reason we don’t start giving flu shots in July.”
Medical providers want to make sure the flu shot is effective when the public needs it most which is why it is widely available beginning in October and November.
“Most of the time in this part of the country, we see the most flu in January or February.”
4. Where are flu shots available?
You can get your flu shot at any Sanford Health location in addition to other locations in your community.
“I would say this year, as much as any other, the less illness we can have from the flu, the better off we’re going to be as we try to continue to get through what’s going to be a very long COVID season,” Dr. Cauwels said.
5. How long are flu shots good for?
This varies from person to person.
“As a general rule, you can say, you’ll be covered for the season that you get it in,” Dr. Cauwels explains. If you get it in the winter months, you’ll be covered for the winter.
“Whether it’s three, four or six months, depending on the person you’re immunizing, is something that we don’t routinely test. I don’t know that there’s a way to do routine testing on that. The flu shot changes every year and because of that, and because the virus changes, what we can’t guarantee is that this year’s flu shot will do the job for next year’s flu.”
6. What is flu and COVID-19 season going to look like?
That’s hard to say at this point because so little is known.
“Right now, Australia is having the lowest flu season they’ve had in years,” Dr. Cauwels explains. “They have 10-times less cases than they’ve ever had before. We think that’s because they’re doing an excellent job of social distancing, an excellent job of wearing masks, and an excellent job of washing their hands. What we don’t know is whether or not the flu shot was also exceptionally effective this year. Australians were vaccinated before we were because their seasons are opposite of ours.”
“What we do know is that flu has been a very small portion of disease in Australia. What we don’t know is whether or not that will hold true to North America when we get into our colder months.”
7. Do flu shots work 100%?
No. Flu shots are not 100% effective.
“Many vaccines that we have are not 100% effective. There are a few that are greater than 95% effective, including childhood vaccines.”
He says the flu virus changes mid-year and in preparation for the upcoming season, experts have to choose which strains go into the vaccine.
“While we can generally put 3, maybe 4 different strains in that dose, there are hundreds of combinations of flu shots and flu viruses. The three we can make with the possibilities that might come into the country is an area of science that involves a lot of infectious disease doctors and epidemiologists. In the end, it’s a prediction of what they think is going to be the best way to go forward.”
8. What are the stages of the flu?
The flu comes in three phases. Interestingly, Dr. Cauwels says, this is where the flu varies somewhat from COVID-19.
“The flu tends to hit you like a ton of bricks. When you get the flu, you know you’re sick on that day.”
- In the beginning, there’s an acute illness phase which can last for 2-5 days
- After that, there’s a semi-recovery phase when you know you’re not feeling well but you’re not getting worse
- During the third, or “recovery” phase, you start feeling better, moving around and eating or drinking more normally
“During that recovery phase, this is the time where a patient is really debating as to whether or not they’re going to go back to work, school or various activities,” Dr. Cauwels explains.
“For most people, the flu is a week-long illness. It’s two days of feeling really crummy two days or three days of holding their own and then a couple of days of getting better.”
9. How long does the flu last?
About a week.
“I’ve certainly met people who’ve had a flu-like illness longer than a week,” he said. In most cases, it depends on the overall health of the individual before coming down with the virus and if there were any other illness or complications present.
“Some people will get out in five days and feel pretty good and others might be sick for closer to 10 days.”
10. What is the difference between Flu A and Flu B?
“If you think about influenza as Lego blocks kids play with,” Dr. Cauwels explains, “the A block and the B block are two different strains of the flu and each one of them can stack different ways to make you sick on top of them. But the A and the B blocks don’t fit together. You can get Influenza A, and you can get Influenza B, but they’re two distinctly different things.”
Dr. Cauwels said generally, the Upper Midwest sees more Influenza A which affects patients more severely. The course of illness is slightly different depending on the strain.
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