PORTLAND, Ore. (KOIN) — The omicron variant of the COVID-19 coronavirus continues to be the dominant strain around the country. The CDC said the BA.4 and BA.5 subvariants of omicron currently make up an estimated combined 20% of COVID cases in the US.

What concerns doctors is data that shows these subvariants are better at bypassing immunity from vaccines and prior infection.

Dr. Gregory Poland, the head of Mayo Clinic’s Vaccine Research Group, said he’s concerned this may cause a summer spike right as kids return to school.

The Oregon Health Authority’s latest vaccine breakthrough report in May shows more than 23,000 vaccinated people got sick with COVID — but only 2% of that group was sick enough to be hospitalized.