SALT LAKE CITY (ABC4) – Health experts predict the Delta variant may become the dominant strain of COVID-19 in the United States by fall. Vaccines have proven highly effective against variants of concern, but University of Utah Health experts said there’s concern for the unvaccinated.

In recent months, the Delta variant has ravaged through India and the United Kingdom.

The latest variant now makes up at least 10% of all COVID-19 cases in the U.S. and is growing at a rapid rate.

“The frequency and percentage of cases caused by the Delta variant in the United States seems to be doubling every week or two,” said Stephen Goldstein, PhD, a postdoctoral researcher at the U of U School of Medicine.

All three COVID-19 vaccines remain effective against the variants of concern, but local health officials said there’s still a race to vaccinate the unvaccinated.

“The best way to get ahead of these variants is vaccination,” said Russell Vinik, MD, the chief medical operations officer at U of U Health.

“Regardless of the particular strain that is circulating most predominately at any given time, it’s going to occur among the unvaccinated and that’s where the spread is going to be,” said Sankar Swaminthan, MD, the chief of division of infectious diseases at U of U Health.

A little more than half of Utah’s eligible population is not fully vaccinated, according to data on the Utah Department of Health website.

“It’s important to understand if you choose to not get vaccinated, ultimately, there is a very high likelihood you will become infected with this virus if the Delta variant becomes dominant,” Goldstein said.

The unvaccinated are a concern for health officials who said the U.S. could face a future like the United Kingdom and India if vaccination rates don’t keep up.

“In India when the dramatic surge occurred, essentially nobody in the country was vaccinated, maybe 2% to 3%,” Swaminthan said.

“In the past, we know what’s happened in the United Kingdom has sort of foreshadowed what’s going to happen in the United States and I don’t think there’s any reason to think that this time will be different,” Goldstein said.

Currently, there are six variants of concern. Public health officials have said the Delta variant is likely to be more contagious than the original virus that spread throughout the world.

Since the end of march almost all COVID-19 cases, hospitalizations and deaths have occurred in unvaccinated Utahns, according to UDOH data, shared by U of U Health on Tuesday.