UPDATE: Second COVID bivalent booster shots set to roll out. Here’s what you need to know

San Francisco Chronicle, by Aidin Vaziri, April 18, 2023 [See also, this article updated: April 19, 2023]

On Tuesday, the U.S. Food and Drug Administration authorized a second COVID-19 booster dose for older Americans and individuals with weakened immune systems to enhance their protection this spring.

Coronavirus map: How many COVID cases are in Bay Area and California

The move comes amid concerns over newer variants of the virus causing the number of COVID-19 cases and deaths to tick back up in the United States, particularly among vulnerable populations.

Individuals age 65 or older may opt for a second shot of the bivalent vaccine targeting the omicron strains of the coronavirus at least four months after their initial dose. For those who are immunocompromised, a second booster shot may be received at least two months later, with additional doses at the discretion of their physician.

The FDA also announced that the original versions of the Pfizer and Moderna vaccines are outdated and will no longer be used. Instead, individuals receiving these shots will be administered the newer omicron-targeted version. For those receiving their first-ever vaccine, a single combo dose will suffice.

According to Dr. Peter Marks, the FDA vaccine chief, “At this stage of the pandemic, data support simplifying the use of Pfizer and Moderna vaccines. The agency believes this approach will help encourage future vaccination.”

Although Britain and Canada have already recommended an additional spring booster for vulnerable populations, high-risk Americans who last received a dose in the fall have been eagerly anticipating another dose.

Booster doses continue to stave off severe disease and death, even as more contagious variants have emerged, while protection against mild infections is short-lived.

At least 250 people in the U.S. still die from COVID-19 each day, many of them older and at higher risk for the worst outcomes of the disease.

Yvonne Maldonado, an infectious disease expert at Stanford, said, “If you look at who’s dying or getting sick now, it’s people who are unvaccinated or unboosted.”

The Centers for Disease Control and Prevention must approve the latest round of boosters, and its advisers are scheduled to meet on Wednesday.

The Pfizer and Moderna boosters contain protection against both the original coronavirus strain and omicron variants known as BA.4 and BA.5. Recent studies show that the bivalent shots are still effective, even as newer omicron cousins circulate.

The FDA’s simplification also means changes for unvaccinated children. Children under 5 may receive two doses of the bivalent Moderna vaccine or three doses of the Pfizer-BioNTech bivalent vaccine.

People 5 and older may get a single bivalent Pfizer shot or two Moderna doses. Children already fully or partially vaccinated with the original Pfizer or Moderna shots may get a bivalent vaccine, but the number of doses will depend on their vaccination history, the FDA said.

While over 95% of the U.S. population aged 65 and older received at least one vaccine dose, only 42.1% of those eligible have received the latest boosters, which were authorized in August, according to the CDC.

The offering of a second bivalent booster will not interfere with the Biden administration’s previously stated plan of moving the nation toward an annual COVID vaccine similar to the flu shot.

But for eligible high-risk groups, a second booster in the spring is a reasonable choice, said Dr. Matthew Laurens of the University of Maryland School of Medicine.

“We do have vaccines that are available to protect against these severe consequences, so why not use them?” he said. “They don’t do any good just sitting on a shelf. So let’s give them to individuals who are at the highest risk and who can benefit the most.”

The Associated Press contributed to this report.