HOUGHTON — The Delta variant has become the dominant strain of COVID-19 in the U.S., accounting for more than 93% of new infections in the U.S. as of last week.

Thursday, the Western Upper Peninsula Health Department announced six cases of the Delta variant of COVID-19, along with a case in Gogebic County.

The variant is caused by a mutation changing a few of the more than 500 amino acids that make up COVID’s spike protein, which allows it to penetrate cells. The changes help the protein bind easier to ACE2, the protein on the cells that allows the COVID virus to enter.

Caryn Heldt, director of the Health Research Institute at Michigan Technological University, likened it to a sticky glue toy kids might throw at the wall.

“The Delta variant just has better glue, and it sticks more often, which then makes it easier to get into our cells and make us sick,” she said.

The Delta variant is up to twice as infectious as the original version of the virus, the Centers for Disease Control and Prevention said. In general, a person sick with the Delta variant will have 1,000 times more virus in their nose than with the original COVID-19, Heldt said.

“Just having so much more virus means that when you sneeze or cough or talk, you’re much more likely to put that virus in the air so someone can breathe it in,” she said. “And then it’s more likely to stick to your cells and make you sick.”

Early data is inconclusive on whether Delta causes a more severe COVID infection. Either way, Heldt said, its spread will result in more hospitalizations by virtue of creating more cases.

“If more people are getting sick, then more people will end up in the hospital and more people will die,” she said.

Vaccines are holding up well against the Delta variant, Heldt said.

“They were never tested to determine if you would have an asymptomatic infection,” she said. “They were never really tested even if you had an infection at all. They were really just, ‘Does it keep you out of the hospital?’, ‘Does it keep you from dying?’ And it does do that.”

Preliminary findings show vaccinated people are also less likely to get infected. Recent data from the Centers for Disease Control and Prevention showed vaccinated people who became infected had the same initial level of virus in their nose; however, when tested a week later, their viral levels dropped much faster than in unvaccinated people.

It also still hasn’t been determined how able vaccinated people who contract COVID are to transit it to other people, Heldt said.

“When we say that you test positive, we’re looking to see if the nucleic acids of the virus exist,” she said. “Testing if that’s infectious or not is a separate test. So we don’t know if vaccinated people are as infectious as unvaccinated, but we do know the level of viruses drop much quicker in vaccinated people once they become infected.”

Natural immunity provides some protection, but how much varies by the individual much more than with vaccination, Heldt said. The most protection against future infections was seen in people who had contracted COVID-19 and then got vaccinated, Heldt said.

While the original COVID-19 virus and early variants were less common among children, the Delta variant has seen a rise in positive cases among the younger population. The Miami Herald reported Monday children under 12 had seen the sharpest increase in COVID-19 cases as Delta has become prominent, increasing sevenfold over the past month.

Heldt would not predict future trends in COVID infections. But she was clear on the best way to reduce future cases: get vaccinated.

“The biggest thing that we have that can end this pandemic is the vaccine,” she said. “They are our strongest chance we have.”