U.S. Accounts for Fifth of All Dangerously Mutated R.1 COVID Variant Cases

The United States has recorded more than one in five of known global cases of a COVID-19 strain that may infect vaccinated people more than previous versions.

There have been 2,266 cases of the R.1 variant reported across 47 U.S. states, according to the latest available data collated by nonprofit Scripps Research.

Globally, there have been 10,573 known cases of the variant, which was first detected in Japan at the end of November 2020.

Scientists fear the variant's mutations could lead to increased resistance to protective antibodies, which are found in the recently infected and the vaccinated.

The R.1 strain, however, is far from the most dominant strain in the U.S. or globally.

Between February 1, 2020, and August 7, 2021, the R.1 strain accounted for less than 0.5 percent of total cases in the U.S. The last reported case was on July 16.

In Japan, where there have been far fewer COVID-19 cases, the strain has accounted for a larger proportion of case, the latest data shows.

Between February 1, 2020, and July 27, 2021, there were 7,521 known R.1 cases—representing about eight percent of all cases.

Dr. Amesh A. Adalja, a senior scholar at Johns Hopkins Center for Health Security, has suggested it is unlikely the R.1 variant will overtake the Delta variant as the most severe or transmissible mutation of the SARS-Cov-2 virus.

"I don't suspect it will be a major problem because it doesn't have the ability to displace Delta," he told Health magazine. "It's really hard for these types of mutations to get any foothold in a country that has the Delta variant present."

Experts, however, are working to asses the threat from any new variants.

In April, the Centers for Disease Control and Prevention (CDC) compiled a report on the R.1 variant after a nursing home in Kentucky was hit by an outbreak.

Of the 26 residents infected, 18 were fully vaccinated; of the 20 infected care workers, four were vaccinated.

Those who had been vaccinated "were less likely to be infected than were unvaccinated persons," the CDC found, while vaccinated people were also "significantly less likely to experience symptoms or require hospitalization," it said.

The outbreak in March was found to have been triggered by an unvaccinated staff member, the Kentucky Department of Public Health said.

Some post-vaccination infections are expected. No vaccine is 100 percent effective against COVID-19, despite having demonstrated high efficacy in clinical trials.

TEM image from America's first COVID-19 case.
File photo: A transmission electron microscopic (TEM) image of an isolate from the first U.S. case of COVID-19 in March, 2020. The spherical viral particles, colorized blue, contain cross-sections through the viral genome, seen as black dots. CDC/Smith Collection/Gado/Getty Images