SAN FRANCISCO (KPIX) — It may get easier for millions of Americans wanting to get the COVID-19 booster starting this week. The U.S. Food and Drug Administration is expected to authorize boosters for Moderna and Johnson & Johnson — and perhaps even more anticipated for some — allow for the mix-and-match of the vaccines.

That means those who want the booster can get one from a different manufacturer than their first two doses. It’s positive news for those who received the Johnson & Johnson shot and have been, so far, left out of the conversation when it comes to boosters.

READ MORE: 1 Reported Wounded in Shooting Outside High School Football Game in Campbell

“I welcome this news, really enthusiastically,” said University of San Francisco Prof. of Medicine and infectious disease specialist Dr. Peter Chin-Hong. “I think ultimately that’s going to be the best advice. Not to really stress over what vaccine you got, just go and get one.”

Dr. Chin-Hong said studies out of the UK, where mix-and-match of vaccines were necessary because of a shortage, were safe and effective. Some studies proved that, in some cases, the combination was even more protective against the virus.

A recent FDA study showed the Johnson & Johnson vaccine, in particular, had a 76% rise in antibodies after a Moderna booster. Much higher than when the Johnson & Johnson was followed by its own booster.

READ MORE: Curry Scores 32 Points as Warriors Top Trail Blazers

When asked whether this may be indicative that boosters may be needed every few months or once a year like the flu shot, Dr. Chin-Hong replied, “That’s a great question. Now if you look back in the history of how vaccines are given, even the common ones we have now, they usually come in threes. Measles, mumps and rubella — you’ve got two shots in the beginning and then a few months later you get another one, and that’s the prime and boost. We also see it with hepatitis B, human papillomavirus. So whatever the reason is, it seems that when we do something in the beginning, you wait a few months, you remind the immune system again. So if COVID doesn’t shape shift too much that our vaccines are worthless, our current immune system may kind of remember stuff for much much longer than a few months after the third.”

In September, the FDA signed off on Pfizer’s booster shot at least six months after the second dose. The agency is expected to authorize Moderna and Johnson & Johnson’s boosters this Wednesday, including mixing-and-matching of vaccines.

Pegge Crisham, 87, just received her COVID-19 booster on Monday, not just because of her age, but because she once was pregnant and had the measles. She said the infectious disease caused her son to be born deaf.

MORE NEWS: Federal Court Blocks COVID-19 Vaccine Mandate for California Prisons

“I really think that the vaccination is important,” Crisham said. “If you’re old enough or your grandparents are old enough to remember polio, we didn’t argue about having the shots. We went and got them and that’s why nobody even knows about polio anymore.”