Is a Combo COVID/Flu Shot on the Way?

WEDNESDAY, Sept. 15, 2021 (HealthDay News) -- During the next few weeks or months, you might find yourself dropping by the doctor's office or pharmacy to get your annual flu shot along with a dose of COVID vaccine.

Unfortunately, you'll have to get two individual jabs. Though at least two drug companies are working on a combo flu/COVID booster, the single-dose shot won't be ready for this flu season.

But rest assured that it's perfectly safe to get your flu shot and COVID vaccination during the same visit, infectious disease doctors say.

Getting several vaccinations at once has been standard medical practice for decades now, and these combos have never caused any harm, said Dr. William Schaffner, medical director of the Bethesda, Md.-based National Foundation for Infectious Diseases.

"It certainly hasn't inhibited the armed forces," said Schaffner, a professor of infectious disease and preventive medicine at the Vanderbilt University School of Medicine in Nashville, Tenn. "When you're a recruit, you get needled. You get a whole bunch of vaccines simultaneously."

It doesn't overwhelm your immune system, he said.

"And the CDC [U.S. Centers for Disease Control and Prevention] has said explicitly you can get your first, second or -- if they're recommended -- booster COVID vaccines at the same time that you get your flu shot," Schaffner added.

Anticipating that annual COVID boosters will be needed in the future, the pharmaceutical companies Moderna and Novavax both have announced that they are developing a combination flu/COVID vaccine.

Moderna told investors last week it hopes eventually to build an annual combo vaccine that protects against a variety of respiratory viruses, including influenza, COVID and respiratory syncytial virus (RSV).

Meanwhile, Novavax said it has initiated early-stage clinical trials to test a combined flu/COVID vaccine.

Don't go looking for either combo shot this flu season, said Dr. Amesh Adalja, senior scholar with the Johns Hopkins Center for Health Security in Baltimore.

"I do not think that this is going to be something available in the short term, especially not for this flu season as flu vaccinations have already become available," he said.

Schaffner agreed.

"They're looking to the future," Schaffner said of the drug companies. "They think COVID boosters will be necessary, and they're even laying their bet this might be a good idea on an annual basis, because that would be the schedule in which you would need to get flu vaccine. They're thinking about that pretty seriously and have invested a bunch of science in it."

Adalja says the combo COVID/flu shot could be a smart idea, if it turns out we do need boosters against COVID.

"The more vaccines that can be packed into one shot the better, as it makes getting vaccinated and staying on schedule convenient," he said. "Whether this is a vaccine everyone needs depends upon the data supporting the need for booster COVID vaccinations, which has not been fully presented."

Lots of other combination vaccines are already on the market, like the tetanus/diphtheria/pertussis (Tdap) and the measles/mumps/rubella (MMR) shots, Adalja said.

Whether a COVID/flu combo would be safe and effective will depend on the immune reaction that's produced by a single jab, Adalja said.

He noted that the MMR and varicella (chickenpox) vaccines are separated for the first dose, and then combined into a single MMRV shot for a person's second dose.

That's because when the combo MMRV is given as one shot for the first dose, it produces more adverse reactions than breaking it into two separate jabs, Adalja said.

Either way, infectious disease doctors like Schaffner and Adalja are bracing for a flu season that could be worse than last year. According to the CDC, flu cases were at an all-time low in 2020-2021 as pandemic protections such as masking and social distancing also served to keep influenza at bay.

"People are concerned because we're doing exactly the opposite of what we did last year," Schaffner said. "We're going out instead of staying home. The kids are in school rather than learning virtually. So we anticipate there will be influenza this year. We can't tell you how much, but we think there will be influenza, so we're going to have to reintroduce everyone to this other respiratory virus which is also nasty -- influenza."

Schaffner is also worried that public health experts will be promoting flu shots "at a time of vaccine fatigue," during which people might also be touting COVID booster shots among some groups.

But it's still anyone's guess what will happen this flu season, Adalja noted.

"It's unclear whether influenza will be a major factor this season because there has not been much flu circulating even in the Southern Hemisphere, and there are some residual COVID-19 mitigation measures that people are taking," Adalja said. "But influenza has a special status, and it is very important to be prepared for whatever the season may hold."

More information

The U.S. Centers for Disease Control and Prevention has more about influenza.

SOURCES: William Schaffner, MD, professor, infectious disease and preventive medicine, Vanderbilt University School of Medicine, Nashville, and medical director, National Foundation for Infectious Diseases, Bethesda, Md.; Amesh Adalja, MD, senior scholar, Johns Hopkins Center for Health Security, Baltimore