Delta variant creates new phase in COVID battle

by Ian Johanson
for The Beacon

It’s much more contagious, a greater percentage of the population will need to get vaccinated, and masking is essential – for schoolchildren and even for the already-vaccinated: that was the consensus from three University of Wisconsin experts in a public livestream event on the Delta variant of the coronavirus July 27.

The event coincided with the revised recommendations announced earlier that day at a separate press briefing by the Centers for Disease Control (CDC) for vaccinated individuals to wear masks in public indoor settings in areas of “Substantial” or “High” transmission. The CDC also recommends universal indoor masking for all teachers, staff, students, and visitors to schools, regardless of vaccination status.

A county-level map of transmission levels is available at the CDC’s Covid Data Tracker. As of Friday Aug. 6, Sheboygan County was rated as “High.”

CDC director Dr. Rochelle Walensky said that the Delta variant behaves “uniquely differently” than past strains and that in “rare occasions some vaccinated people infected with delta after vaccinations may be contagious and spread the virus to others.”  This new science required the updated recommendations, she said.

In the UW presentation, UW Medical Foundation Professor of Pathology and Laboratory Medicine David O’Connor, PhD, presented a just-released chart from Public Health Madison & Dane County demonstrating the new science behind the new recommendations. It showed that the amount of virus detected in the nasal swabs from COVID-positive Dane County individuals was “just about the same” for both the vaccinated and unvaccinated.

“We have some people who have really high amounts of virus, even though they’ve been vaccinated,” he said. “You might be a super-spreader, even if you’ve been vaccinated.”

“It’s also important to remember that the vaccine protects from severe disease, and that’s great. So even if you’ve been fully vaccinated, and even if you have this really high amount of virus in your nasal swab, you’re not likely to get sick, you’re not likely to be hospitalized, and you’re not likely to die.”

Dr. Jeff Pothof, an associate professor of clinical health sciences in the School of Medicine and Public Health cited a study from China’s equivalent of the CDC which showed the viral load in the nasopharynx (the upper part of the throat behind the nose) 1,260 times higher than the native disease. “That just lends pretty good credence to the idea that this is much more contagious.”

Pothof said that the question about whether Delta is more dangerous – whether it can cause more severe disease – “is yet unanswered,” despite some studies suggesting that it might.

Regarding masks in schools, Pothof said the decision by many school districts to make masks optional was at a time when cases were really low and Delta was not being discussed. “Right now that’s just a decision that doesn’t work when we’re talking about the safety of our kids. Delta’s much more contagious, we want to get kids in school, which means we’re probably going to have to cheat on distancing, which means we can’t cheat on masking.”

Ajay Sethi, PhD, an associate professor in the department of population health sciences, described COVID vaccinations as a “race against the variants.” “The Delta variant started the race earlier. It was detected in India in October 2020, before the vaccine era, and it was responsible for the surge that India experienced, that they’re now sort of recovering from.” It spread around the world, to the United States, and “it’s wreaking havoc,” he said.

An unvaccinated person on average would spread the original version of the virus to 2-3 other people, Sethi said, while for the Delta variant that’s estimated to be spread to about six other people.

“That leads to a greater exponential growth in cases in communities.”

Sethi said the CDC estimates that 83% of new COVID infections are caused by the Delta variant. The highest levels of transmission of the Delta variant are occurring in areas where people are largely unvaccinated, he said. However, every single state has been experiencing a rise in COVID transmission.

“Breakthrough infections” for vaccinated individuals are “relatively rare, and most will have no symptoms or mild illness. However, vaccinated or not, the viral load is similar and a reason for the new masking recommendations.” “The vaccines remain highly effective against severe disease and death.”

“There is really no county in the country that has enough people vaccinated, simply because the Delta variant is so much more infectious. That 70 percent threshold we used to talk about is old news. We’ve got to be in the high 80’s, 90’s now, which we haven’t achieved anywhere. So I think we have to go back to our precautionary principle, and take the necessary precautions.”

A full recording of the 1 hour UW video discussion can be viewed at

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