(The Hill) – The Food and Drug Administration (FDA) on Tuesday released updated guidance on COVID-19 vaccinations, in what the agency described as a move to “simplify” future immunizations.

Much of the FDA’s simplification involves recommending only a single dose of the bivalent COVID-19 vaccines created by Pfizer and Moderna for most people. 

These are the vaccines that target the original Wuhan strain of the SARS-CoV-2 virus along with the BA.4 and BA.5 strains of the omicron variant, and were first made available about 7 months ago. 

The original COVID vaccines are no longer authorized for use in the U.S. after the FDA’s vaccine advisory panel in January voted unanimously to essentially phase them out for the bivalent boosters. 

FDA officials believe this new schedule will boost vaccine coverage throughout the country.

With the official end of the national COVID-19 public health emergency less than a month away, this move towards shorter, simpler vaccine schedules marks another step by the Biden administration away from the pandemic era of COVID-19.

Here’s what to know about the new guidance:

You are eligible for one bivalent dose if…

  • You have completed a primary series of COVID-19 vaccinations and have never received a dose of the updated bivalent version.
  • You have never received a COVID-19 vaccine

This new guidance represents a relatively large portion of the U.S. population. Only 16.7 percent of eligible individuals have received an updated booster shot, according to the Centers for Disease Control and Prevention (CDC).

Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, said there was evidence to support a simplified vaccine schedule. As he noted, most of the U.S. population is believed to have COVID-19 antibodies, either from prior infection or immunization.

Exceptions for at-risk groups

The FDA’s new guidance broadly authorizes single additional doses of the updated vaccine, but groups who have been at a higher risk throughout the pandemic are exempt from the new rule  — to a certain extent:

  • People over the age of 65 who have already gotten a bivalent booster can get a second dose at least four months after the first one.
  • Certain immunocompromised individuals can receive one or more additional doses beginning at least two months after getting a bivalent booster, at the “discretion” of their healthcare provider.
  • Young children are still eligible for multiple-dose vaccine schedules: A two-dose series of Moderna’s bivalent vaccine for children between six months and five years. A three-dose series of Pfizer’s bivalent vaccine for children between six months and four years.
  • Five-year-olds have the option of two doses of Moderna’s or one dose of Pfizer’s bivalent vaccines.
  • Children between six months and five years of age, who finished a primary series of the old vaccines, can get the bivalent vaccine. The FDA said the number of doses will depend on “vaccination history,” though further explanation was not provided.

Guidance going forward

The CDC’s Advisory Committee on Immunization Practices (ACIP) will meet on Wednesday to discuss the new vaccine guidance. A vote on vaccine recommendations does not appear to be on the committee’s meeting agenda, however.

Guidance on future doses of COVID-19 vaccines is expected later this year in preparation for the fall season, in a process reminiscent of how annual flu vaccines are approved.

“The FDA intends to make decisions about future vaccination for all the various populations after receiving recommendations on the fall strain composition at an FDA advisory committee meeting to be held in June,” Marks said in a briefing on Tuesday.

Fewer doses could also help ease the impact of the expected price hikes for COVID-19 vaccinations, which will no longer be subsidized by the federal government once the public health emergency comes to an end.

Both Pfizer and Moderna have proposed steep price increases for their respective vaccines, with the burden of covering the cost shifting to health insurance companies. 

Though both drugmakers have stated that their shots will remain free to consumers, health care stakeholders have warned that insurance companies may pass the price increases on to customers through higher premiums. 

Uninsured individuals will be able obtain free doses through the companies’ in-house patient assistance programs.