With an incoming COVID surge, health officials push urgently for boosters. Do you need one?

Facing yet another COVID-19 variant, this one said to be faster and stealthier than those before it, health officials say the calculus has changed and are urging booster shots even more strongly to buck up the country’s armor.

There is a renewed push for everyone over 5 to go out and get a first booster shot if they haven’t yet. That’s the majority of Americans since despite evidence of significant improvements in protection against hospitalization and death from the third shot since only 48% of Americans have gotten a third shot, according to data from the Centers for Disease Control and Prevention.

Officials are also urging a second booster shot, about four months after the first booster shot, for people who have received their first boosters but are considered high-risk, including people 50 and older and the immunocompromised.

“For people who are 50 years of age or older, my message is simple. If you have not gotten a vaccine shot in the year 2022 -- if you have not gotten one this year, please go get another vaccine shot,” White House COVID-19 Response Coordinator Dr. Ashish Jha said during a press briefing on Tuesday.

“If you've not gotten a vaccine shot this year, go get one now. It could save your life,” he said.

The Food and Drug Administration and the Centers for Disease Control are also considering widening that eligibility to include all adults in the next few weeks, Jha said.

But the newfound urgency to offer second boosters to younger populations has been met with confusion, particularly after federal officials previously suggested that shots for people who weren’t high risk wouldn’t be necessary until the fall.

And even for those over the age of 50, prior guidance on the CDC’s website stated that if getting a shot now would make you hesitant to get one in the fall, you should wait until fall to get a second booster. The emergence of the omicron subvariant BA.5 appears to have changed that calculus, however.

Why does BA.5 change the urgency of booster shots?

BA.5, which is now estimated to account for 65% of new COVID-19 cases in the U.S. according to CDC data, became dominant earlier this month. It brought with it a surge of cases and hospitalizations, which will likely be followed by deaths.

It seems to be the most immune-evasive variant the world has seen so far, in terms of its ability to get around past protection from bouts with COVID and from the vaccines.

That means people who have already had COVID-19 are still at risk of becoming reinfected.

And that decline in protection, paired with a new variant that’s better at getting around the vaccine, poses a renewed threat.

“The frequency of BA.5 infections are rising across the US, for those that have not been vaccinated in several months, immunity has likely waned,” C. Buddy Creech, director of the Vanderbilt Vaccine Research Program and associate professor of pediatric infectious diseases, told ABC News.

So who should get one?

Even if you’ve already had COVID-19 and even if you plan to get a booster this fall, when variant-specific vaccines are expected to be available, experts who spoke with ABC News widely agreed that eligible people should still ensure they are up to date with their COVID-19 vaccinations and booster shots.

“If I had not gotten booster number two already, I would get it today,” Dr. Bob Wachter, chair of the department of medicine at the University of California, San Francisco, told ABC News.

“You can get a painless, free, and essentially risk-free intervention that will lower the probability of mortality, hospitalization and, at least for a while, infection, at a time when the virus is absolutely rampant,” Wachter said. “That seems like a pretty easy call to me.”

Wachter said the risks of another booster shot is less than most of the procedures he does daily in his job at the hospital, and carries a big benefit.

“The booster is about as safe as anything we do. So my threshold to give it when I think there might be benefit is pretty low,” he said.

What if you’ve recently had COVID?

Though the CDC recommends waiting about three months after having COVID-19 to get vaccinated, experts watching BA.5 said they thought people should consider getting a shot one or two months after recovering.

“I have shortened up my timeline. If you got infected a month or more ago, and you're eligible for a booster now, I would go ahead and get it,” Wachter said.

Because BA.5 may better can evade prior infection compared to previous variants, people who got COVID recently shouldn’t consider that to be as strong of protection as it once was.

“For anybody who was infected prior to a month ago, an educated guess would be that it wasn't BA.5, and therefore, your immunity is not good for as long as it used to be,” Wachter said.

Dr. Anna Durbin, director of Center for Immunization Research at Johns Hopkins University, said she would also wait a month, or perhaps two months for people who are lower risk.

“You want your immune system to cool down a bit before you give another vaccine because once it's cooled down, then you get the biggest effect from that vaccination,” she told ABC News.

“That recent infection is going to provide you with an immune response that will keep you out of the hospital. It is a better booster than the vaccine because it is more aligned with what's currently circulating,” added Durbin.

Dr. David Dowdy, an infectious disease epidemiologist at Johns Hopkins Bloomberg School of Public Health, agreed that the need for a booster shortly after infection is not pressing, as the added value of a booster shot that soon is “relatively small.”

What about the boosters coming this fall?

Even though the U.S. is expecting a new booster campaign this fall with updated, variant-specific vaccines, several experts encouraged getting a booster now, in light of BA.5, and then again in a few months, when the new vaccines arrive.

“There's this theoretical risk of over-boosting but we've been at this now for two years, we have people having gotten two, three, even four shots — and I think it remains a theoretical risk,” he told ABC News. “I don't think there's any strong evidence that is true.”

Durbin said she thinks people who get a booster now would also have enough of an interval between shots for another booster this fall or winter to still have a strong impact.

“Because it's July now, there's enough of a window between that booster and then the Omicron-specific booster that you should get a really good benefit from that in the fall,” she said.

If health agencies recommend a booster for younger people, should they get one?

For younger people, if the FDA and CDC decide to open up eligibility for second booster shots, experts agreed that it would be worth it to re-up protection in certain cases.

“I would say the benefit outweighs the risk, certainly,” Durbin said.

It won’t eliminate the chance of getting COVID, though, and people shouldn’t expect it to because of how fast the virus has evolved since the original vaccines were created.

“We have to really be careful in our messaging and manage people's expectations, otherwise they're not going to want to get boosters in the fall that are more specific for Omicron and may prevent infection far better than the current vaccine does,” Durbin said.

That said, other experts were more conservative in their recommendations for young people.

“While the benefits of vaccination certainly outweigh the risks, I'm not sure that it's more urgent now than before to get younger people yet another booster,” said Dowdy.

“If anything, hospitalizations in the BA.5 era are increasingly among people 70 and older, so the focus on people under 50 isn't really following what we see in the data.”

And particularly for young people who have recently had COVID, Wachter, too, said it would be reasonable to wait until the fall.

“I'd say for a truly low-risk person, a healthy young person with three shots and gets COVID now, then I'd be on the fence and I probably wait until the fall,” Wachter said.

Creech added that although some younger Americans may feel hesitant to get the booster now and in the fall, most people will understand the continued threat of COVID-19 and the need to maintain protection.

“I think people recognize that a new COVID variant seems to always be lurking around the corner and vaccines are the best prevention we have,” Creech said.