A Combination COVID-Flu Vaccine May Be Just Around the Corner

Convenience of single shot would boost protection for older adults against both viruses

Rachel Nania,

AARP

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En español

Published October 01, 2024

/ Updated October 17, 2024

Photo Collage: AARP (Source: Shutterstock)

Millions of Americans are making plans this fall to get their flu and COVID vaccines — two separate shots that ramp up the body’s defenses against two different viruses. But pretty soon, these same people may need only one poke instead of two for the same protection.

Vaccine manufacturers are racing to develop a combination vaccine for influenza and COVID-19, and one maker says its version could be available as early as 2025.

In a late-stage clinical trial with thousands of study participants ages 50 and older, individuals who received a combined coronavirus-influenza shot from Moderna generated a better immune response against flu and COVID-19 than participants who received the individual vaccines. What’s more, the side effects of the hybrid jab experienced during the phase 3 trial were nothing new, with the most common reactions being injection site pain, fatigue, muscle pain and headache.

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Pfizer-BioNTech is also working on a combination vaccine, though the team recently faced a setback when the experimental inoculation failed to meet one of the main goals of a phase 3 clinical trial. In a news release, Pfizer said “the companies are evaluating adjustments to the candidate and will discuss next steps with health authorities.”

Similarly, Novavax, another COVID-19 vaccine manufacturer, has a combination COVID-flu vaccine that just wrapped phase 2 clinical trials. Further research is currently on hold to investigate "a spontaneous report of a serious adverse event of motor neuropathy" in a trial participant, Novavax said in an Oct. 16 news release. The company said it does not believe the condition was caused by the vaccine, and that it hopes to resolve the matter and begin the phase 3 trial "as soon as possible."

Single shot could boost vaccination rates

Plenty of people have received their flu and COVID vaccines at the same time — some even in the same arm. Still, health experts are hopeful that combining the two into a single shot will increase the number of people who get vaccinated against both illnesses.

“A lot of times, people just don’t want to get two pokes at the same time, so they schedule one [vaccine] now and then have the intention to come back in a few weeks and get the second one. And then what happens, if they never get the second one, they just go without that vaccine,” says Ann Philbrick, a pharmacist and associate professor and director of community engagement in the University of Minnesota College of Pharmacy. A two-in-one shot “might help with completion of getting both of the vaccines,” she adds.

William Schaffner, M.D., professor of preventive medicine and infectious diseases at Vanderbilt University School of Medicine, says one jab instead of two may also appeal to more people and could potentially boost the number of individuals getting vaccinated.

Vaccination rates have been declining in recent years, national data shows. About 23 percent of adults in the U.S. received last year’s coronavirus vaccine, according to the Centers for Disease Control and Prevention (CDC), and less than half of adults got a flu shot last year. A new report from the National Foundation for Infectious Diseases finds that only 38 percent of U.S. adults say they definitely plan to get a flu shot this year, and 26 percent plan to get the updated COVID vaccine.

Plus, Schaffner says, combining the two vaccines just makes a lot of sense. Both viruses are especially active in the fall and winter months, and the recommendations “are identical for the two vaccines,” he explains. The CDC says most people ages 6 months and older should receive a flu shot and an updated COVID vaccine this fall.

Side effects should be similar

If a blend of two different vaccines sounds strange, know that it’s “very common to put more than one vaccine in a shot,” Philbrick says. Several vaccines given to young children are combination vaccines; a few examples include the measles, mumps and rubella (MMR) vaccine and the tetanus, diphtheria and pertussis (Tdap) vaccine.

Squeezing two vaccines into one shouldn’t double the side effects or cause any new reactions. “Many people have already elected to get both shots at the same time [in the same or different arm],” Schaffner says. “And there’s no evidence that there is a notable increase in adverse reactions, and these early trials by Moderna don’t indicate that there is any concern in that regard.”

Get both standalone vaccines this year

Schaffner says Moderna’s results, while not yet published in a peer-reviewed journal, “[makes us] optimistic that the vaccine will be at least as good as our current vaccines, and maybe even better.” But until a combination COVID-flu vaccine is approved and available — Moderna says it expects to start the federal approval process in 2024 — it’s crucial to get the two separate shots this fall.

“We know that there’s going to be a big outbreak of flu. We know that there’s going to be a big outbreak of COVID. How big? We don’t know, but there will be an outbreak of each and these viruses bring many people into the hospital, and obviously, as a consequence, cause many deaths. We want to protect as many people as possible this winter,” Schaffner says.

Also: Adults 75 and older who didn’t get the RSV vaccine last year should plan to get it this year, health officials say. It’s recommended that adults ages 60–74 with underlying health conditions like heart and lung disease get the RSV vaccine, as well.

Editor's note: This story, first published Oct. 1, 2024, has been updated to include new information. 