SAN FRANCISCO (KGO) -- Over a month ago, omicron's subvariant BA.2.12.1 became the dominant strain across the country. Fast forward to this week and now the CDC confirmed BA.4 and BA.5 combined are responsible for the majority of cases in the U.S.
"They are taking off like wildfire. They can escape our immune system," said Nadia Roan, Associate Investigator at Gladstone Institutes.
RELATED: U.S. buys 105 million COVID vaccine doses for fall campaign
This CDC graph shows Omicron's BA.4 and BA.5 making up over 52% of infections nationwide. As more research goes into how BA.4 and BA.5 behave there are two studies providing early data points.
One suggests BA.4 and BA.5 appear to escape antibodies from vaccines and prior infection. Experts from UCSF and Stanford explain.
"Even if you had some immunity from prior infection like BA.1 you are still at high risk of getting reinfected with these variants. They potentially find a way around immune response also in cause of infection. This is why they outcompete the dominant strain. Because they are more transmissible and can get around the immune system," said Abraar Karan, Infectious Diseases at Stanford University.
Another study suggests BA.4 and BA.5 may target the cells in our lungs.
RELATED: Women are more likely than men to develop long COVID, study finds
"There is a study that came out of Japan suggesting that in a laboratory dish when you put human lung cells there that BA.4 and BA.5 can make more copies of themselves as compared to the original omicron," said Roan.
"These things have a lot of mutations in them. Sometimes these mutations lead to greater ability to bind to cells. Specific types of cells called alveolar cells that are deep in the lung tissue. As opposed to the ones in the upper airway. I think that is what may be going on. Whether it's clinical significance or not is another question," said George Rutherford, UCSF Professor of Epidemiology.
Nadia Roan, Associate Investigator at Gladstone Institutes is working on research to help the human body fight at the entry point.
EXCLUSIVE: Here's how COVID is detected in wastewater throughout CA
"Ways to boost the mucosal immunity," said Roan. "We can do a better job at eliciting protection against actual infection in the respiratory tract."
Dr. Karan says wearing your mask and getting vaccinated still work against these sub-variants.
"The same measures that can reduce transmission by airborne pathogens and airborne spread will work regardless of variant," said Karan.
RELATED STORIES & VIDEOS:
- Americans keep getting reinfected with COVID-19 as new variants emerge, data shows
- Study shows people are recovering from COVID in a week but testing positive for over 10 days
- Never had COVID? Expert explains chances of getting it now
- EXCLUSIVE: Here's how COVID is detected in wastewater throughout CA
- New studies shed light on how to treat BA.2 COVID variant, how long it survives on surfaces
- Map shows COVID-19 community levels in your area, where masks are recommended indoors
- Coronavirus Timeline: Tracking major moments of COVID-19 pandemic in San Francisco Bay Area
- Here's how to take a rapid COVID-19 test accurately at home
- Data tracker: Coronavirus cases, deaths, hospitalizations in every Bay Area county
- Get the latest updates on California EDD, stimulus checks, unemployment benefits