AUSTIN (KXAN) — The Biden administration plans to ship out millions of doses of updated Pfizer and Moderna booster shots this September, it confirmed to NBC News Friday. The altered shots will better protect against BA.4 and BA.5, health leaders say.

The boosters will come late for many who have already contracted the subvariants of omicron, but it could help wrap up a surge in Austin that researchers at the University of Texas’ COVID-19 Modeling Consortium say could otherwise last until October.

We took questions about the Biden administration’s plan to Texas health leaders, including Austin Public Health and the Texas Medical Association’s COVID-19 task force. Here’s what you need to know.

I haven’t gotten a booster shot yet — should I wait?

While nearly 18 million eligible Texans completed their first round of COVID-19 vaccines — whether that be the two dose Moderna and Pfizer vaccines or the one dose Johnson & Johnson vaccine — less than 40% of those people followed through with a booster shot, according to data from the Texas Department of State Health Services.

Dr. Charles Lerner with the Texas Medical Association’s COVID-19 task force said if you’re up-to-date on vaccine, you should hold off until the fall to get another shot. For people who are behind on immunizations and due for a booster, he said you should both get one now and then again in the fall.

Right now, the CDC only recommends a second booster shot for people who are 50 or older and people who are immunocompromised. It recommends everyone five and older have one booster shot to this point.

What is different about these shots?

Because the virus is changing with every variant and subvariant, both Pfizer and Moderna have begun the process of altering their vaccine to better protect against the most recent version of the virus.

NBC News reports both companies have acknowledged the September deadline set by the president’s administration and believe they’ll have updated vaccines ready to go.

“The booster shots in the fall will contain a component which is specific for the omicron variety of COVID-19. Previous boosters were aimed only at the original strain of the virus,” Lerner explained.

I got COVID recently, do I still need a booster in the fall?

While Lerner said there are no official recommendations about whether to get a booster this fall if you’ve recently had COVID-19, he did tell us he still recommends it.

“Personally, I would recommend the immunization,” he said. “Infection with the BA.5 strain does not produce significant immunity to reinfection. There are reports of people getting reinfected within a month of a BA.5 infection.”

Who will get the booster shots?

There won’t be enough doses, initially, to get every American up-to-date on vaccine with the altered shots, NBC reported.

APH said it has not yet received guidance from the CDC regarding fall booster shots and a spokesperson said “regulators must first sign off on the modified vaccinations.”

While local and state health agencies were the only entities giving vaccines during the early stages of the pandemic, that’s no longer the case. Pharmacies like Walgreens, CVS and H-E-B will have access to the updated booster shots, as will other clinics and doctors offices.

How many boosters am I going to need?

Lerner said because the spike proteins in these viruses mutate quickly, we’re going to be getting regular booster shots for a while, but that may not always be the case.

“If the current strain of the virus is replaced by a new strain, the omicron component of the vaccine this fall may not have much benefit,” he explained, but also noted research is being done on a vaccine that could provide more long-lasting immunity.

“In October, a trial is scheduled to begin on a different vaccine aimed at a conserved portion of coronaviruses. These proteins do not mutate. If this vaccine is effective and the immunity is long lasting, we may not need boosters,” Lerner said.