Federal officials are expected to recommend a COVID-19 vaccine booster shot for most Americans soon, and the guidance could go into effect by mid-September.
The U.S. Food and Drug Administration has already authorized an additional vaccine dose for people with compromised immune systems.
Josh Guist headed to Hayat Pharmacy soon after the FDA amended its authorization, saying his treatments for multiple sclerosis compromise the vaccine's efficacy.
"I want every possibility I can to be as protected as possible," Guist said. "I want to protect myself, and all the people I care about, and strangers as well."
Milwaukee's Health Department just started offering the extra shot for people with weakened immune systems on Tuesday.
Health experts stressed there is a difference between the authorized additional doses to increase immunity for people who are immunocompromised, and the booster shots federal officials are expected to recommend for a broader population.
"What we're learning is that after a two-dose series, they don't develop the immunity that we first heard about in the trials, the 94-95% effectiveness. It's much lower, but if we give those individuals a third dose, they start to develop increased immunity against COVID-19. So for the immunocompromised, not so much a booster, it's really part of their initial series," said Dr. Jeff Pothof with UW Health.
A booster that is being discussed now would apply eight months after a person got his or her second Pfizer or Moderna shot. Doctors said there is not enough information to say if this would apply to those who received the single-dose Johnson and Johnson vaccine.
This comes after a key study suggested some waning of the immune response over time.
"Now this is also likely coupled with increased transmissibility and severity of the currently circulating delta strain. The information on booster doses is still coming out and we'll continue to follow the evidence," said Dr. Ben Weston, chief health policy adviser for Milwaukee County.
Dr. Pothof emphasized that discussions about a booster do not mean the vaccines are not working.
"If you're currently vaccinated, even with delta, even if you don't get a booster, your likelihood to survive an infection with COVID-19 is exceedingly high, but what we are seeing is increased breakthrough cases, and that's concerning because that might mean that people who are vaccinated could spread the disease to other people," Dr. Pothof said.
Pothof added that spread could severely sicken or kill people who are unvaccinated, and it could give the virus more chances to mutate and become resilient against vaccines.
Dr. Weston does not think booster shots are key to reversing the rising COVID-19 trends, considering the vast majority of infections, severe cases, and deaths are among those who are not vaccinated. Rather, the booster would help maintain immunity in people who are vaccinated.