What’s next with COVID-19 vaccines or boosters?

Updated 4/4/2023 – This post was updated with a link to the Center for Disease Control and Prevention’s website for the current schedule of COVID-19 vaccinations.

Available in Spanish

photo of someone getting a vaccination in their arm

A lot of people want to know the answer to this question. For example, will federal health officials authorize a second dose of the bivalent booster? Will there be an entirely new vaccine formula available next fall? And if so, will it be a flu-COVID-19 combo shot?

At this point we don’t have a lot of concrete answers, but we can shed some light on a few possibilities and developments.

The near future

The most likely scenario is that there won’t be another booster shot available until the fall (for those who are up to date on their COVID-19 vaccinations). Fall is when the respiratory virus season ramps up, and although COVID-19 has not yet followed a seasonal pattern, fall is the ideal time for vaccinating against respiratory viruses because people start to spend more time indoors. It’s also when most people get the annually updated flu vaccine.

Fortunately, the single-dose bivalent booster that became available in September (replacing the monovalent booster) has proven to be effective against Omicron subvariants. That includes the predominant strains currently circulating in the U.S.—XBB and its offspring, XBB.1.5, perhaps the most contagious COVID-19 subvariants yet. Data show those who are up to date on their vaccinations, including the bivalent booster, have significant, long-term protection against severe COVID-19 illness, and shorter-term protection (a few months) against being infected with mild to no symptoms.

But if we start to witness a notable rise in COVID-19 cases and hospitalizations before the fall, federal authorities could authorize a second dose of the bivalent booster.

The next vaccine

The U.S. Food and Drug Administration’s (FDA) advisory committee last month voted unanimously to simplify the next phase of COVID-19 vaccines, also discussing guidance for who gets what shot, how many shots they need and when they receive them. Visit the Centers for Disease Control and Prevention’s website for the current schedule of recommended COVID-19 vaccinations.

Yes, it’s complicated.

The FDA panelists shared a desire to simplify the entire process, starting with the vaccine composition. The panel voted unanimously that the next vaccine should contain the same formula for both the primary series and boosters. Whether the formula is monovalent or bivalent (to be determined), there would be no difference between the primary series vaccine and the booster doses in terms of ingredients and manufacturing. It is likely the formula would be updated each year, like the flu vaccine, in time for a fall rollout.

Whatever vaccine formula is created for the U.S. population, it may not be the same formula used in other countries. COVID-19 strains and levels of transmission vary across regions, and creating a uniform COVID-19 vaccine to protect everyone in the world equally is nearly impossible.

Incidentally, scientists have tried for decades to develop a uniform flu vaccine for the world—a “game changer” that could save hundreds of thousands of lives every year. Although those efforts have been unsuccessful so far, the research and development of COVID-19 vaccines has advanced that research.

Beyond the vaccine formula, the FDA panel also discussed (but did not vote on) potential guidelines for administering the vaccines.

Possible future guidelines and key points

  • People who haven’t received a primary series will still need one. Receiving a primary series would be a one-time event, followed by an annual booster received in the fall.
  • People who have completed a primary series would receive a single booster dose periodically—perhaps annually—with an updated vaccine formula introduced each fall.
  • The primary series might be a two-dose series for certain populations, such as young children, older adults, those with compromised immune systems and people who have not been infected with the COVID-19 virus. For everyone else (with a prior COVID-19 infection essentially acting as the first dose), the primary vaccination series would consist of one dose.
  • Pfizer and Moderna would likely continue to be the primary vaccine suppliers, using mRNA technology in their vaccines.
  • The federal government has just extended its partnership with Novavax, agreeing to purchase 1.5 million doses of its non-mRNA vaccine for the public. Novavax would likely also update its vaccine formula annually.
  • The future of Johnson & Johnson’s (J&J) COVID-19 vaccine is unknown, but the federal government has not extended its relationship with J&J and purchased more doses. That means the J&J vaccine would likely disappear in the U.S.

A flu-COVID-19 combo shot

Pfizer is conducting a clinical trial with people ages 18 and older to study an mRNA combo vaccine against COVID-19 and the flu. It is conceivable this combo vaccine, if authorized, would become available in 2023, but it is too early in the process to predict.

Pfizer is also conducting a separate clinical trial with people ages 18 and older to study an mRNA vaccine against only the flu. Both products would be unprecedented, as there has never been a flu vaccine using mRNA technology authorized for use in the United States. Additionally, Moderna has been working on an mRNA flu vaccine for years and is also currently conducting clinical trials for it.

mRNA technology is important because it allows for the frequent and speedy updates to the vaccine formula required for a virus that mutates as quickly and often as the COVID-19 virus.

For now, we know that the bivalent COVID-19 booster works. It targets the currently predominant subvariants and provides significant protection against severe illness. It’s available to everyone ages 6 months and older who has completed a primary vaccination series at least two months prior. To find a COVID-19 (or flu) vaccine near you, go to Vaccines.gov, or call 211 or your local public health department.

To read a summary of the FDA’s meeting, click here.