Do I need a second COVID-19 booster?

In guidance that was nuanced — and some might say confusing — regulators stopped short of recommending that everyone over 50 get another booster. Instead, they said those with underlying medical conditions would especially benefit from an extra boost, as antibodies that protect against infection begin to wane. In other words, they gave people the option of getting a booster without flat-out recommending that they do so.

By authorizing a second booster now, U.S. authorities hope to guard against a new surge in cases as they observe upticks in parts of Europe and Asia from the BA.2 variant now dominant in the United States.

The move has gotten mixed reactions from experts, with some saying that the evidence to support a second booster remains limited.

Who is now approved to get what, exactly?

The Food and Drug Administration authorized a second booster dose of the Pfizer-BioNTech or Moderna vaccine to anyone 50 and older whose first booster was at least four months ago.

This means that those in this age group who got the two-dose series of Pfizer or Moderna mRNA vaccines and then a booster can now get a fourth dose. Those who received the single-dose Johnson & Johnson (Janssen) vaccine, and then a booster of mRNA vaccine, also can get a second booster, for a total of three shots.

In addition, for all adults 18 and older who received two shots of J&J vaccine, regulators authorized a second booster dose using mRNA vaccine.

The FDA authorized a fifth dose of mRNA vaccine for teens and older with moderately or severely compromised immune systems, such as organ transplant recipients taking immune-suppressing medication. For immunocompromised individuals, three mRNA shots can be considered the primary series, since for many, it took more doses to stimulate an adequate initial response from the immune system.

The immunocompromised person who received a single dose of the Johnson & Johnson vaccine can now receive a total of four vaccine doses — a J&J dose and one Pfizer or Moderna dose as the primary vaccine series, and two boosters of mRNA vaccine.

Who might benefit from a second booster?

“Boosters are safe, and people over the age of 50 can now get an additional booster four months after their prior dose to increase their protection further,” said Dr. Rochelle Walensky, director of the Centers for Disease Control and Prevention.

“This is especially important for those 65 and older and those 50 and older with underlying medical conditions that increase their risk for severe disease from COVID-19 as they are the most likely to benefit from receiving an additional booster dose at this time,” Walensky said in a statement to the media.

The CDC’s list of these medical conditions is long. It includes common conditions in the 50-plus age group such as being overweight, diabetes and “possibly high blood pressure.” It also includes cancer and chronic kidney, liver or lung disease, to name just a few.

Why did the CDC stop short of a blanket recommendation that everyone 50-plus get a second booster?

“COVID-19 vaccines continue to offer high levels of protection against severe disease, hospitalization, and death —especially for individuals who are boosted,” CDC representative Kristen Nordlund said in an email.

However, with cases of COVID-19 rising again in some parts of the world — and the possibility that the U.S. will experience an uptick in the coming months — the federal government’s action “allows individuals the option of increasing their protection now,” Nordlund said.

“Another booster dose could help restore protection that may wane over time, and provide peace of mind for those who want optimal protection as soon as possible.”

What’s the evidence that a second booster is needed?

Peter Marks, a top vaccination official with the FDA, said that current evidence suggests some waning over time of vaccination’s protection in older and immunocompromised individuals.

“Based on an analysis of emerging data, a second booster dose of either the Pfizer-BioNTech or Moderna COVID-19 vaccine could help increase protection levels for these higher-risk individuals,” Marks said in a statement.

U.S. officials point to data out of Israel, which for months has been administering second boosters. For example, one study that has not yet been peer-reviewed found that after a fourth dose of mRNA vaccine, the rate of infection was two times lower and the rate of severe disease was four times lower in those 60 and older.

Not all researchers find the evidence convincing. Dr. Paul Offit, a member of the vaccination advisory panel to the FDA, said the studies didn’t use control groups, instead tracking only people who opted for a second booster.

The booster-choosers could be particularly conscientious about their health, skewing the findings, he said.

Should I get a booster if I’m over 50 and in good health?

Offit said that most evidence suggests that a single booster continues to protect the majority of people against severe disease, which he said is the goal of vaccination.

Whether a person needs a second booster dose comes down to how healthy they are, some authorities say.

“It’s a complicated question,” said Dr. Cort Lohff, chief medical officer for the Southern Nevada Health District.

“It comes down to an individual assessing their own risk,” including considering their own medical conditions that might place them at higher risk, and whether those conditions are well controlled.

Lohff, who is 56, said he’s gotten his first booster, has had COVID-19, and is “a pretty healthy person.” So he does not plan to rush out and get a second booster.

Family practitioner Dr. David Weismiller, a professor at the Kirk Kerkorian School of Medicine at UNLV, said he’d advise patients with a severe medical condition — such as late-stage kidney disease, undergoing chemotherapy or a recipient of a transplanted organ — to get a second booster now. But he sees no urgency for a patient with well-controlled high blood pressure or diabetes, he said.

An exception would be for his patients who have received only the J&J vaccine, with new data indicating they would benefit from a dose of mRNA vaccine, Weismiller said.

When in doubt, patients ought to seek guidance from their own physician, Weismiller and Lohff said.

Should I wait until fall to get another boost?

Many vaccination authorities believe that periodic boosting may be necessary with COVID-19 vaccines or that an annual shot may be needed to fend off the variants that are currently in circulation.

But this doesn’t mean that it’s either safe or effective to get unlimited, unnecessary doses. There is always the risk of the side effects associated with the immune response, such as fever and headache.

Too many doses can also backfire by exhausting the immune system, said Offit, director of the Vaccine Education Center at Children’s Hospital of Philadelphia and a professor at University of Pennsylvania’s Perelman School of Medicine. The body may lock into its response to the virus and respond less effectively when a new strain appears.

This makes the timing of a booster dose important.

“If you’ve got one more bullet in your pistol the question is, when do you fire?” said Dr. William Schaffner, an infectious disease professor with Vanderbilt University and a nonvoting member of the vaccination advisory committee to the CDC.

“My sense is you wait until you really have a well-defined problem, which we do not have in the United States at the present time, in my humble opinion,” said Schaffner, who doesn’t believe that second boosters are yet warranted for most people.

Weismiller said that another surge in cases and hospitalizations could create a greater sense of urgency.

“If we have a surge of some variant, and we are seeing increased hospitalizations and potential for death, that may be the time that we need to boost,” Weismiller said, with the booster becoming effective in two weeks.

But the challenge is predicting when another surge might occur, Lohff said — and in getting protected before it’s too late. For that reason, he suggests those with underlying medical conditions consider getting a second boost now.

Where can I get a second booster?

Second booster doses are available at Southern Nevada Health District clinics for people 50 and older.

They also are available for people 12 and older who are immunocompromised, provided it has been at least four months since they received their first booster dose.

Second booster doses also are widely available at pharmacies.

The shots are free to the patient. In some cases, insurance companies may be billed for the administration of doses, Lohff said.

Contact Mary Hynes at mhynes@reviewjournal.com or 702-383-0336. Follow @MaryHynes1 on Twitter.