Doctor Urges Public to Wear Face Masks as BA.4 and BA.5 Omicron Subvariants Spread

Two highly-transmissible mutations of the omicron COVID-19 variant are gaining traction across the country, including in the Chicago area, leading some doctors to recommended the use of face masks indoors once again.

The BA.4 and BA.5 subvariants now account for the majority of new COVID cases in the U.S., according to health officials. As of July 2, the subvariant BA.5 was responsible for nearly 54% of COVID cases. BA.4 accounted for nearly 17% more, data from the Centers for Disease Control and Prevention showed.

David Montefiori, a professor at the Human Vaccine Institute at Duke University Medical Center, told NBC News that BA.4 and BA.5 are about three times less sensitive to neutralizing antibodies from existing COVID vaccines than the original version of the omicron variant, BA.1. Additional research suggests that BA.4 and BA.5 are four times more resistant to antibodies from vaccines than BA.2.

When it comes to symptoms, runny nose, sore throat, headache, fatigue and persistent cough appear to be most common of the fastest-spreading variants, according to Dr. Jonathan Martin, an infectious disease physician with Cook County Health.

This past week, Cook County moved out of "high" COVID community level risk, the highest of three levels classified by the CDC's community level status map. According to the most recent data, only two Chicago-area counties - DuPage and Lake - are still at "high."



"The issue now is the tests are not reported to the health department, so the numbers the health department is getting right now don’t necessarily reflect the number of COVID cases out there," Martin said.