MINNEAPOLIS (WCCO) — Last week, the Centers for Disease Control changed its mask guidance after learning some vaccinated people can spread the coronavirus to others. Due to the Delta variant, the CDC is now recommending that fully vaccinated people who live in areas of “substantial or high” COVID transmission to wear mask indoors.

So, what is different about the Delta variant? Good Question.

“There are still lots of things that are unpredictable about this variant,” says Dr. Louis Mansky, director of the Institute for Molecular Virology at the University of Minnesota.

According to the Minnesota Department of Health, the Delta variant spreads twice as easily from one person to another. Experts say the way the virus mutated allows it to bind more tightly to the receptors in on human cells. That makes the viral titers, or amount of virus, is about 1,000 times higher compared to previous versions of the virus

So if the viral load is so much higher, does inside versus outside even matter anymore?

Dr. Gregory Poland, a professor of medicine at the Mayo Clinic College of Medicine, says it does.

“Clearly when you’re outside, you’re diffusing virus into a huge volume of air and those aerosols tend to move away,” he says. “That’s not true indoors where generally you don’t have much in the way of air current.” Even so, he still recommends wearing a mask if a person is outdoors with a lot of people nearby.

Experts say the quality of mask does matter, perhaps even more with the Delta variant. Research has found masks not only slow down droplet transmission, but also decreases the chance the mask-wearer will get infected with the virus particles.

“A high quality N95 mask is going to afford you a much better level of protection, especially if you fit it and wear it properly,” Former FDA Commissioner Dr. Scott Gottlieb told CBS’ Face the Nation last Sunday. “So, quality of mask is important.”

Researchers are trying to determine if the Delta variant is causing more serious illness. Poland says preliminary data hints that it does.

“We would think with a higher viral titer, it makes sense that disease is worse, but it’s hard to actually definitely pin that down, he says. Anecdotally, Poland says the consensus in the U.S. is that kids are getting sick from the Delta variant as well.

Both Mansky and Poland say getting the vaccine is the best defense against the virus. Data has shown the vaccines not only prevent serious disease, but can help slow community transmission, and thus, virus mutation.

“I can’t tell you whether it’ll become a virus that’s seasonal, but I don’t think the perpetual running around will last forever,” Mansky said.

At the same time, he also points out the biggest unknown about the Delta or any future variants: What’s next?

“Not only could it get worse, but many experts believe that it will,” Poland said.

Heather Brown