This season’s flu and COVID-19 vaccines

Judith A. O’Donnell of the Perelman School of Medicine answers common questions about this year’s flu shot and the new COVID-19 vaccines.

Four bottles of Influenza vaccine beside one medical syringe.
Image: Bernard Chantal for Adobe Stock

With flu season around the corner and the ongoing uptick in COVID-19 cases, many have questions about the vaccines for both viruses. 

Penn Today spoke with Judith A. O’Donnell, a physician and section chief of the Division of Infectious Diseases at Penn Presbyterian Medical Center and a professor of infectious diseases at the Perelman School of Medicine, to learn about this year’s flu shot and the new COVID-19 vaccines. “Flu and COVID vaccines provide real-world, real-life benefits, and I strongly recommend that everybody considers getting them,” O’Donnell says.

Who should get the annual flu shot, and when?

Anybody 6 months and older should get the flu vaccine. It has benefits for everyone.

In terms of timing, you never know exactly when flu season is going to start, but most typically flu season kicks off in December, peaks in January, and then kind of peters out through February, and it’s usually gone by March. The vaccine is going to give you good protection for about four to six months, so October is a good time to get your flu vaccine; it’s safely before the season starts, and, if for some reason flu season gets a late start and doesn’t peak until March, you’re still going to be protected.

How effective is this year’s formulation expected to be?

The flu vaccine changes year to year, and the components that are used in the flu vaccine are decided upon based on what’s circulating in the southern hemisphere before we move into our winter season here in the northern hemisphere. We won’t be able to definitively determine if it’s a good match, and therefore provides good protection, until we know what’s circulating here in the northern hemisphere.

But the important thing to recognize is that, even if it’s not a great match, everybody gets some level of an immunity boost when they get the flu vaccine, and what is most important about the flu vaccine is that it prevents you from getting severely ill and it keeps you out of the hospital. I’ve taken care of many patients who were completely healthy and could be considered low risk for a serious flu infection but got flu, were very sick, required hospitalization, and in some cases were in the hospital for several weeks. The bottom line is that anybody can get flu and become severely ill, and the flu vaccine prevents severe illness.

Is there anything different about this year’s flu shot recommendations?

One thing that’s new this year is that if a patient reports a history of an egg allergy, they can still safely receive the vaccine, and they can be treated like anybody else in terms of getting the vaccine without any additional period of observation after vaccination to ensure no allergic side effects.

The CDC recently approved two new COVID-19 vaccines, produced by Moderna and Pfizer-BioNTech. How are these new vaccines different from last year’s booster shots?

These are new updated vaccines, and the great news is that they are going to give you immunity to what is circulating right now in the community.

The new vaccines are different from the bivalent booster vaccines that came out about a year ago in that these are now monovalent vaccines, meaning they only target one COVID subvariant. The bivalent vaccine used two strains of COVID—the original strain from 2020 and then an early Omicron strain—but at this point we know the only virus strains circulating are the Omicron subvariants, so there was no reason to keep that original virus strain in the updated vaccine formulation.

Who should get the new COVID-19 vaccine?

Everyone can benefit from this vaccine, and I would encourage everyone to strongly consider getting it. We are seeing a consistent uptick in COVID cases over the last six weeks, and we don’t expect that to reverse course anytime soon. Getting the vaccine now will really help prevent you from getting infected.

I would highly recommend it in anybody who is 50 or older, anybody who has any chronic medical conditions, including being overweight, having asthma as well as more serious diseases like heart disease, cancer, diabetes, liver disease, kidney disease, and anybody who smokes.

There are benefits for young, healthy people as well. I know from having conversations with patients that in that situation there’s some questioning—I’m young, I feel fine, I work out regularly, I’m a normal weight, and I don’t smoke—so what’s the benefit to me? My conversations with those patients are usually around who do you know, because you may want to get the vaccine so that you don’t get infected and pass it on to someone in your life like your new baby or your elderly grandparent or your sibling who’s just undergone a transplant.

When should people get the new COVID-19 vaccine?

If you haven’t had COVID in 2023, you should get the COVID vaccine now, or soon, even if you were boosted last fall or in the spring.

If you had COVID in the summertime of this year, I would say to wait a little bit because that infection is going to give you a fair amount of immunity, so you really don’t need the boost from this new vaccine yet. An infection usually gives you a boost in immunity for around four to six months, so I suggest timing the new vaccine to be at least three or four months from your infection. However, if you are one of these people who is immunocompromised and don’t really know if you’re not making good antibodies to infections or vaccines, then you may want to get the vaccine soon, even if you were recently infected. You should discuss this with your health care provider.

Another thing to layer into your decision about timing is, what are your plans for the late fall and early winter in terms of holiday gatherings or traveling? The vaccines give you the most immunity for around three months after you get them, and after that the antibodies wane a little bit, so some people may want to time their COVID booster for the end of October or early November so that they’re getting peak immunity in time for Thanksgiving and the winter holidays. But the people who have that luxury are the people who are otherwise fairly healthy.

What sort of protection does the COVID booster offer?

It doesn’t completely protect you from getting infected, and none of the earlier vaccines have done that, either, but it absolutely does prevent against severe disease. The data tell us that vaccination prevents patients from ending up in the hospital with COVID, requiring supplemental oxygen, requiring a ventilator, or having to go to an ICU setting and dying from COVID.

Does vaccination help prevent long COVID?

We don’t know a lot about these new vaccines and prevention of long COVID, but what the published studies have told us thus far is that vaccination, with or without having had infection, seems to somewhat prevent long COVID. There is still much that is unknown about long COVID, but what we have learned is that those who are vaccinated are at lower risk of developing it.

Can you get the flu shot and the new COVID vaccine at the same time?

Yes, you can do it, and, yes, I would recommend it. It’s a personal decision, but, if you’re like me and you want to get everything over at once, just roll up both sleeves, get one in each arm, and you’re good to go, and you don’t have to make two separate appointments.

Wellness at Penn is hosting its annual flu clinic in the first week of October. The Candyland-themed Flu Clinic will take place over three days: Wednesday and Thursday, Oct. 4-5 from 10 a.m.–6 p.m, and on Friday, Oct. 6, from 10 a.m.–4 p.m. The clinic will be held in the Gimbel Gymnasium, at Pottruck Health and Fitness Center and is free and open to the University community, including students, faculty, postdocs, and staff. Penn Cards are required.