The BA.4 and BA.5 Omicron subvariants are now the predominant COVID-19 variants in Oregon and across the United States. They have led to rising COVID-19-related hospitalizations, including ICU admissions. BA.4 and BA.5 are slightly more transmissible than the BA.2 Omicron subvariant, which was significantly more transmissible than the early COVID-19 variants.
While the current COVID-19 vaccines may not protect everyone from catching the virus, they remain effective at preventing severe illness and death. Everyone age 6 months and older is eligible to receive a COVID-19 vaccination, so entire families can be better protected from the virus.
Scientists aren’t yet sure whether BA.4 and BA.5 cause more severe disease than previous variants.
“Hospitalizations are rising because more COVID-19 is spreading in our communities and because community-level immunity has decreased since the early Omicron surge last winter,” said Melissa Sutton, Oregon Health Authority’s (OHA) medical director of respiratory viral pathogens. Immunity from a COVID-19 infection may only last a few months. As time passes after someone gets infected, more people again become susceptible to infection, leading the virus to spread more widely.
Spread of disease
“Recorded cases are approaching levels seen during the Delta wave, but we know that we’re only detecting a small fraction of cases overall,” Sutton said.
To figure out the scope of the virus’s spread, OHA experts instead look at the test positivity rate, or “percent positivity,” which shows what proportion of tests are coming back positive and is a more accurate measurement of disease transmission than case rates. Percent positivity has traditionally been used to monitor the statewide spread of other respiratory viruses, such as the flu. If the percent positivity goes up, scientists know that the virus is spreading more. Experts also look at wastewater surveillance data, which shows levels of virus in a whole community. Again, if those numbers rise, it’s likely the virus is spreading more.
Last week, Oregon Health & Science University (OHSU) released a new forecast for how COVID-19 – specifically its BA.4 and BA.5 subvariants – may affect people in Oregon. As of last week, 423 people were in the hospital with COVID-19, and OHSU predicts that number to peak at 479 by mid-July.
As with any COVID-19 variant, there are ways to protect yourself. Most importantly, make sure you’re fully up to date with all your vaccinations and boosters. Even though you can be infected with BA.4 and BA.5 despite vaccination, the vaccines remain very effective at protecting you against severe illness and death.
Also consider wearing masks in public indoor places like retails stores, movie theaters or gyms, and move any social activities outdoors, whether it’s to your backyard, a local park or a restaurant patio. When you do wear a mask, choose a well-fitting mask that provides a high level of protection. You can also double up and wear a cloth mask over a surgical mask (not the other way around).
If you’re planning to visit with someone who is immunocompromised or otherwise vulnerable to severe illness, consider taking additional precautions including testing, even if you’re not experiencing symptoms.