New COVID Strain Has Reached the US

Ralph Ellis

September 23, 2021

Editor's note: Find the latest COVID-19 news and guidance in Medscape's Coronavirus Resource Center.

A strain of COVID-19 first reported in Japan surfaced at a Kentucky nursing home in the spring.

Deadline, citing a CDC report, said 26 residents and 20 workers tested positive for COVID-19 at a skilled care nursing home. The facility has 83 residents and 116 employees.

On March 1, 28 specimens that had been subjected to whole genome sequencing were found to have "mutations aligning with the R.1 lineage," Deadline said.

About 90% of the facility's residents and 52% of the staff had received two COVID vaccine doses, the CDC said. Because of the high vaccination rate, the finding raises concerns about "reduced protective immunity" in relation to the R.1 variant, the CDC said.

However, the nursing home case appears to show that the vaccine keeps most people from getting extremely sick, the CDC said. The vaccine was 86.5% protective against symptomatic illness among residents and 87.1% protective for employees.

"Compared with unvaccinated persons, vaccinated persons had reduced risk for SARS-CoV-2 infection and symptomatic COVID-19," the CDC said. The vaccination of nursing home residents and health care workers "is essential to reduce the risk for symptomatic COVID-19, as is continued focus on infection prevention and control practices," the CDC said.

Since being reported in Kentucky, R.1 has been detected more than 10,000 times in the United States, Forbes reported, basing that number on entries in the GISAID SARS-CoV-2 database.

Overall, more than 42 million cases of COVID have been reported since the start of the pandemic.

Deadline reported that the R.1 strain was first detected in Japan in January among three members of one family. The family members had no history of traveling abroad, Deadline said, citing an NIH report.

The CDC has not classified R.1 as a variant of concern yet but noted it has "several mutations of importance" and "demonstrates evidence of increasing virus transmissibility."


Deadline: "New R.1 Covid Variant Detected In U.S. Outbreak; First Identified In Japan"

CDC. "COVID-19 Outbreak Associated with a SARS-CoV-2 R.1 Lineage Variant in a Skilled Nursing Facility After Vaccination Program — Kentucky, March 2021"

Forbes: "A New US/Japan Variant To Watch"


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