UW-Madison study reveals virus abundant in COVID-19 cases in Wisconsin, even among fully vaccinated

MADISON, Wis. (CBS 58) -- In a COVID-19 update released by UW-Madison Thursday, Aug. 5, UW officials announced that some vaccinated people infected with COVID-19 in Wisconsin in June and July had just as much virus in their nasal passages as newly infected unvaccinated people.

The results were released in a new study published Saturday, July 31, by researchers at the University of Wisconsin–Madison, Public Health Madison & Dane County and Exact Sciences.

Researchers say the findings match a Centers for Disease Control and Prevention study released a day earlier describing an outbreak centered on a town in Massachusetts.

The release stated that although the study's researchers did not examine it directly, the researchers suggest fully vaccinated people who get sick with COVID-19 could still potentially infect others.

In the study, analysis of nearly 300 COVID-positive samples collected in Wisconsin between June 28 and July 24 showed no significant difference in “viral load” between 79 fully vaccinated people and 212 unvaccinated people.

Both the vaccinated and unvaccinated study subjects had high viral loads at the time of their positive tests — levels shown in previous studies to be substantial enough to make them contagious to others.

Despite the findings, researchers say that vaccinations are still necessary to receive since the available vaccines against the virus are effective even against the delta variant, and are crucial in preventing new, dangerous cases of the virus.

“They’re still working to keep people from becoming infected, though not necessarily as well as they were against earlier types of the virus,” says David O’Connor, a UW School of Medicine and Public Health professor, co-author of the new study and, with Thomas Friedrich, a scientist at UW–Madison’s AIDS Vaccine Research Laboratory, which has been collecting genetic samples from positive COVID tests since March of 2020. “As long as the vaccines are keeping people out of the hospitals, I would say they’re working spectacularly well.”