Answering COVID-19 vaccine questions: Will I need a booster shot? Can you mix-and-match vaccines?

Vaccine doses are not size or weight based

People still have a lot of questions about the COVID-19 vaccines. Local 4′s Dr. Frank McGeorge is working to answer as many as possible.
People still have a lot of questions about the COVID-19 vaccines. Local 4′s Dr. Frank McGeorge is working to answer as many as possible.

DETROIT – People still have a lot of questions about the COVID-19 vaccines. Local 4′s Dr. Frank McGeorge is working to answer as many as possible.

READ: More answers to COVID-19 questions

“Does a person’s weight impact the size of the vaccine?”

The answer is no, the vaccine doses are not size or weight based.

“Can you mix-and-match vaccines?”

That viewer said, “My husband’s first vaccine was made by Moderna, his second vaccine was by Pfizer. Is he vaccinated? Should he just go get the second Moderna, or get the second Pfizer?”

He is done. He doesn’t need a third shot of either vaccine.

It is uncertain how he received different vaccines between the first and second shot but that’s less than ideal. Nonetheless, the CDC guidance is that when two different vaccines are inadvertently administered, the person does not require additional doses.

This situation highlights the reason everyone should be sure to keep their vaccine card form of the first dose to be sure you receive two of the same vaccine.

“Can you contract COVID more than once?”

The answer is generally no, at least for awhile.

The immunity you develop from being infected should protect you for at least 3 months. We don’t have enough information yet to be able to say for sure how long immunity lasts beyond that.

READ: How long are you immune after recovering from COVID-19?

However, there are case reports of people being reinfected. While this appears to be uncommon, variants might become problematic.

Reports: 2 people reinfected with COVID-19 had more severe symptoms the second time

There’s developing information that vaccines may not protect as well against the south African variant b.1.351. And if the protection from vaccines is incomplete, it’s possible the protection from having been infected by “COVID classic” is also incomplete.

Although it might turn out that infection with a different variant might be possible after a vaccine or prior infection, it’s likely that there would at least be protection from more severe disease.

Does this mean we might need a booster shot for different variants of the virus down the road?

That’s something the vaccine manufacturers are already considering. Fortunately, the mRNA technology makes it much easier to update a vaccine if needed, but right now, the current vaccines appear to be effective against the variants that are circulating widely in the United States.

Related: Detroit to hold COVID vaccination fairs at churches for seniors, offer $2 rides to TCF Center

More: Meijer to launch COVID-19 vaccine clinics at Michigan stores: What to know


About the Author:

Dr. McGeorge can be seen on Local 4 News helping Metro Detroiters with health concerns when he isn't helping save lives in the emergency room at Henry Ford Hospital.