New COVID variant BA.5 making up more than 50% of cases in Wisconsin, possibly most contagious virus ever

MILWAUKEE (CBS 58) -- Health experts in Milwaukee County are warning about a rise in COVID infections caused by a variant of omicron that may be the most contagious yet.

BA.5 now makes up more than 50% of infections in Wisconsin.

"Each time [the variants] become more transmissible, which means they're easier to catch from somebody else," Dr. Ben Weston said.

Dr. Ben Weston with the Milwaukee County Health Department said on average, one person infected with BA.5 can spread the virus to over 18 people.

"Which means it's one of the most, if not the most contagious virus we know of. Measles is 18, the most contagious virus out there, and this looks to be even higher than 18," Dr. Weston said.

Whether you previously had COVID or are vaccinated, Dr. Weston said the virus is also evading immunity.

"This previous paradigm that you have 90 days or three months for immunity is really out the window now. It can be just a matter of weeks and unfortunately with this new strain, you can get reinfected," Dr. Weston said.

Dr. Weston said the concern with repeat infections is that you risk getting sicker each time. Your risk of getting long COVID also goes up.

"With each subsequent infection, that risk increases and increases, so you want to avoid getting infected once or three times or four times because that risk increases and continues," Dr. Weston said.

Doctors are also concerned because hospitalizations are also increasing, which is a sign infections are also rising. Since last week, the health department said hospitalizations jumped 16% in Wisconsin.

Dr. Ben Weston is urging you to get boosted if you have not already. People ages 50 and up and those who are immunocompromised are now eligible for a second booster.

"It prevents that severe disease and that hospitalization and death from COVID infection. Fact of the matter is though, that it does not protect you as well from getting infected. We're going to see more and more breakthrough infections," he said.

That's where Dr. Weston is recommending masking up again in places where you can't social distance.

"When you're indoors in public, thinking about distancing, thinking about ventilation," he said.

Dr. Weston said Pfizer and Moderna are working on an omicron-specific booster that could be available in the coming months. He said this booster could help prevent infection from the omicron variants.