Is There a Combination COVID-19 and Flu Vaccine? Not Yet, But There Could Be Soon

As flu season approaches and concerns about COVID-19 continue, you may be wondering whether a single vaccine could protect against both illnesses. Today, flu and COVID vaccines are available separately. But a combination vaccine that protects against the flu and COVID may be a reality sooner than you think. Here's what you should know.

Are there any combination COVID and flu vaccines available?

No, there isn't a combination COVID and flu vaccine available yet. But there could be one as early as 2025.

As of now, the flu and COVID vaccines are administered separately. And since many people are eligible for both vaccines at the same time, they're sometimes given during the same vaccine appointment. In this case, a combination vaccine could cut down on the number of shots you receive. It can also help ensure that you're up to date with recommended vaccines.

Challenges in developing a combination vaccine

Developing a combination COVID and flu vaccine has its own unique set of challenges. The process is more complex than simply combining two shots.

One challenge is that the flu vaccine needs to be reformulated each year to match the most prevalent strains of the influenza virus. The COVID vaccines may require different adjustments depending on new viral variants. And the variants change frequently, causing surges throughout the year. This is different from vaccines given routinely during childhood, some of which are available in combination shots. Unlike the flu and COVID vaccines, the formulations of these vaccines do not change.

Another challenge is ensuring that combining both vaccines into a single shot doesn't affect how well they work for each illness. Researchers also need to make sure that the combination vaccine doesn't cause new, unexpected side effects. This testing process takes time to confirm if the vaccine is both safe and effective.

Combination COVID and flu vaccines in testing

Moderna, Pfizer, and Novavax manufacture the COVID vaccines available in the U.S. All three companies are testing their specific COVID vaccine in a combination COVID and flu shot. Each company is also testing its own flu vaccines in separate studies.

The Moderna and Pfizer combination vaccines use messenger RNA (mRNA) technology that provides your immune cells with instructions to make parts of the viruses. The Novavax combination vaccine contains proteins from each virus, along with a substance to boost the immune response (called an adjuvant).

Here's where they're at in the development process.

Moderna flu and COVID vaccine

Moderna, the manufacturer of the Spikevax COVID vaccine, has a combination COVID and flu vaccine in development with promising results.

A phase 3 trial studied the Moderna combination vaccine in adults ages 50 and older. Results showed that the combination vaccine resulted in a better immune response compared to either vaccine given separately in people ages 65 and older. This age group is especially vulnerable to severe illness. A better immune response was also seen with adults ages 50 to 64 years old.

Based on these results, Moderna expects to submit an approval request to the FDA by the end of 2024. Moderna also has a combination vaccine for adults ages 18 to 49 years old in early stage clinical trials.

Pfizer flu and COVID vaccine

Pfizer, the manufacturer of the Comirnaty COVID vaccine, also has a combination shot in phase 3 trials. The vaccine is being studied in adults ages 18 to 64 years old.

Results from the trial showed that the Pfizer combination shot resulted in a comparable immune response compared to Comirnaty given separately. It also resulted in a higher immune response to influenza A compared to the flu vaccine. But the immune response to influenza B was lower. Influenza A and B are the two types of flu viruses circulating during flu season.

Based on these results, Pfizer is looking at adjusting the combination vaccine for better protection against influenza B.

Novavax flu and COVID vaccine

Novavax is planning to launch a phase 3 trial for its combination COVID and flu vaccine during the second half of 2024. The vaccine, which was developed in collaboration with Sanofi, will be studied in adults ages 50 to 75 years old in this trial.

Earlier, a phase 2 trial tested different formulations of the Novavax combination vaccine, with positive results. This was to determine which ones had comparable responses to the COVID and flu vaccines given separately. These formulations will be tested in the phase 3 trial.

When could a combination COVID and flu vaccine be available?

As covered above, there are three combination COVID and flu vaccines in phase 3 clinical trials - the last step before the manufacturer applies for FDA approval.

Moderna appears to be the furthest along. If everything goes as planned, it's possible that the Moderna flu and COVID vaccine could be available as early as the 2025-2026 respiratory virus season. The Novavax combination vaccine could launch in 2026. Timing on Pfizer's vaccine may be available later on.

Keep in mind that even if a combination vaccine is approved, the flu and COVID vaccines will still be available separately. This is important since you may not need to get both at the same time. For example, people who recently had COVID may postpone their COVID vaccine dose for 3 months. But they may want to get their flu shot sooner. And sometimes, certain groups of people are advised to get additional COVID vaccine doses.

For those who are eligible for both vaccines around the same time, a combination vaccine could simplify their annual vaccination routine.