MADISON, Wis. — Millions of Wisconsinites are already fully vaccinated.  The question now is, will the Moderna and Pfizer COVID-19 vaccines be enough to provide lasting immunity? 

The short answer is, it's too soon to tell.

Dr. Jim Conway, Medical Director for the UW Health Immunization Program, said there are two factors that will determine if and when a booster is needed.

First, researchers have to figure out how long immune protection lasts. "We do that both following people clinically that have illness and then the other is actually people in the studies continue to get testing done to see how good their immunity is," Dr. Conway explained.

The second factor according to Dr. Conway is will the current vaccines still provide good immunity against variants as they start showing up.

He called this process "business as usual in the vaccine world." Dr. Conway said all vaccines, when they come out, need to be followed to see if a booster is necessary.  

"We continually add in boosters as we learn more," he commented. "Now people get tetanus shots every five or ten years. Chickenpox vaccine.   We thought one dose might be sufficient, but now we give shingles vaccine to boost people later. So, this is constantly an evolving science."

Dr. Conway shared, right now, the vaccines are working very well against all variants circling in the U.S. He pointed out we know immunity lasts at least six months for most of the vaccines.  

When it comes to Pfizer and Moderna Dr. Conway said, "remember those have been in studies since last spring, and so we've got almost a year of data on those showing that not only is the immunity strong, in many cases, it seems to get better as time goes on."

Companies are required to submit data every six months; those studies last two years.  

If there starts to be what Dr. Conway called a "significant breakthrough" in disease or when there are new variants that require a new vaccine, he said that's when we will need boosters.

Right now, he said the focus should be on the unvaccinated. Dr. Conway urged, "help them understand they really need to protect themselves, protect their loved ones so that they are continuing to be able to help boost herd immunity or this community immunity which is really what's going to get us into being able to manage this and keep it managed especially as we get into fall."