What to expect with third vaccine doses and why they're necessary

MILWAUKEE, Wis. (CBS 58) -- About three percent of Wisconsin's population is currently eligible for a third vaccine dose, according to state health officials.

But as time goes on, doctors say the booster will be a good idea for the rest of the population thanks to the Delta variant.

People who have weakened immune systems and fall into certain categories laid out by the U.S. Centers for Disease Control and Prevention are eligible for a third dose.

Hayat Pharmacy has had people lining up even before the pharmacy opens to get the third dose of the COVID-19 vaccine. Pharmacists are getting phone call after phone call with questions.

"It's really a great idea to get the third dose because remember, their immune system is not as strong as somebody else who is not immunocompromised," said Hashim Zaibak, owner of Hayat Pharmacy.

Zaibak said getting a third dose is the same process and has side effects as the first two doses.

"I think as the variants come out and we're finding more and more people who are not wearing masks, I will definitely feel safer," said Kathy Donovan, after receiving her third vaccine dose at Hayat Pharmacy on Friday, Aug. 20.

The two dose vaccine series is now considered a three-dose series for people with weakened immune systems. People who are immunocompromised have to wait 28 days after their second dose before getting a third dose.

"I take corticosteroids on a regular basis, which put me in one of the groups," Donavan said.

Boosters aren't available to the rest of the population yet. Dr. Jeff Pothof, chief quality officer with UW Health, said getting a booster will be important first for people who got vaccinated at the end of 2020 and beginning of 2021.

"If you were vaccinated in May, June, July, your antibody levels are still really high, so those folks shouldn't be worried right now about having to try to find a booster dose as soon as it becomes available," Pothof said.

But as time goes on, he said the antibodies start to wane as the virus gets smarter.

"The idea that you're not going to be exposed to Delta variant -- that's just not based in reality at this point. It is too widespread. It is too infectious. Sooner or later, Delta is going to be at your door," Pothof said.

But he said what is even more important than thinking about boosters right now is for people to get vaccinated with their first and/or second doses. Only about half Wisconsin's population is fully vaccinated.

"That third dose is really preventing mild disease, preventing spread, preventing creation of mutants. Those first and second doses -- those that are preventing death," he said. "So if we have a shortage of vaccine because of boosters, we've got to make sure people who are unvaccinated get to get first dibs."

The federal recommendation is the general population could get a booster eight months after Pfizer or Moderna. That still has to be approved by the FDA.