Who needs a second COVID-19 booster shot? Here’s what to know

A motorist receives the COVID-19 vaccine at the Forum in Inglewood .
Staff and volunteers distribute the COVID-19 vaccine to people in their vehicles at the Forum in Inglewood in January 2021.
(Al Seib / Los Angeles Times)

Many Americans can now get a second COVID-19 booster shot, but it’s hard to tell who really needs another dose at the moment and who can wait.

The Food and Drug Administration this week authorized extra Pfizer or Moderna shots for anyone 50 or older and for some younger people with severely weakened immune systems. It’s an effort to get ahead of a possible next coronavirus surge, especially with the highly contagious BA.2 Omicron subvariant now spreading.

With COVID-19 cases low in the U.S. at the moment, it’s easy to ignore calls for another dose — or, for those who aren’t yet vaccinated or boosted, to catch up, said Dr. Erica Johnson, an infectious disease specialist at the American Board of Internal Medicine.


Her advice: If you’re on the fence, talk to your doctor about how protected you really are — and need to be.

Who is eligible for a second booster?

Anyone 50 and older can get the extra dose at least four months after their last vaccination. So can severely immune-compromised patients, such as organ transplant recipients, as young as 12.

Adults can choose either the Pfizer-BioNTech or the Moderna vaccine for their extra shot, but Pfizer is the only option for children.

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What about people who got Johnson & Johnson shots?

Adults who received Johnson & Johnson’s single-dose vaccine already were eligible for a booster of any kind, but the Centers for Disease Control and Prevention recommends that only some of them get a second booster.

A new study found that a Moderna or Pfizer second booster shot was superior to getting a second Johnson & Johnson dose. So the advice is that anyone who got a second Johnson & Johnson shot now can choose a Moderna or Pfizer dose.

But if they already had one of those other boosters, the CDC says only those who meet the newest criteria — age or weakened immune system — qualify for another.


What prompted the move?

Vaccines still offer strong protection against severe illness and death, but effectiveness against milder infections wanes months in a few months. The shots also don’t work as well against new variants like the super-contagious Omicron strain as they did earlier in the pandemic.

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That’s why everyone 12 and older, regardless of their health, already was urged to get a first booster for the best chance at fending off Omicron. Only about half of those eligible have.

With the new BA.2 Omicron variant causing spikes in infections in other countries, officials are nervous that the U.S. is next, prompting efforts to offer extra protection to the most vulnerable.

What’s the evidence for another booster?

Many scientists say it’s limited, leaving public health officials to use their best judgment.

During the U.S. Omicron wave, two Pfizer or Moderna doses plus a booster were 94% effective against death or getting sick enough to need a ventilator, according to a recent CDC study. That protection was lowest — 74% — in immune-compromised people, although most hadn’t gotten the third dose.

Israel began offering people 60 and older a second booster during its Omicron surge. Preliminary findings posted online last week show there were fewer deaths among people who chose another booster compared to those who skipped the fourth dose.


The FDA decided to set the age limit at 50 instead of 60 because that’s when chronic illnesses like heart disease or diabetes become more common, leaving people more vulnerable to serious COVID-19.

An Israeli panel said research shows a fourth COVID-19 shot provides three to five times as much protection against serious COVID-19 as three doses.

Jan. 25, 2022

Who really needs a second booster?

The CDC says an extra shot is an option, but those most likely to benefit are those most vulnerable to severe disease, including people 65 and older and people in their 50s who have multiple health problems.

When should I get it?

Again, experts have differing opinions, partly because it’s not clear how long any extra benefit lasts.

“We can never really perfectly time when the next wave is or when someone might encounter infection,” said Johnson at the American Board of Internal Medicine. “To be as ready as possible, I think everyone just needs to stay as up-to-date as possible with their vaccines.”

Another dose now may make sense for older people and the immune-compromised, but “there’s less urgency in an otherwise healthy person,” said University of Pennsylvania immunologist E. John Wherry.

At 50, Wherry said he’s healthy enough to watch if cases rise enough to prompt another booster, but he’d prefer to wait until fall. That’s because going longer between vaccinations allows the immune response to better mature and strengthen.