A coronavirus variant known as “mu” or “B.1.621” was designated by the World Health Organization as a “variant of interest” earlier this week and will be monitored by the global health body as cases continue to emerge across parts of the world. It is the fifth variant of interest currently being monitored by the WHO.
Where was it first detected and where is it now?
The variant was first detected in Colombia in January 2021, where cases continue to rise. It has since been identified in more than 39 countries, according to the WHO, among them the United States, South Korea, Japan, Ecuador, Canada and parts of Europe.
How widespread is mu in the United States?
About 2,000 mu cases have been identified in the United States, so far, according to the Global Initiative on Sharing All Influenza Data (GISAID), the largest database of novel coronavirus genome sequences in the world. Most cases have been recorded in California, Florida, Texas and New York, among others.
However, mu is not an “immediate threat right now” within the United States, top infectious-disease expert Anthony S. Fauci told a press briefing on Thursday. He said that while the government was “keeping a very close eye on it,” the variant was “not at all even close to being dominant,” as the delta variant remains the cause of over 99 percent of cases in the country.
Mu has yet to be designated a variant of interest or concern by the Centers for Disease Control and Prevention, which did not immediately respond to a request for comment from The Washington Post.
The California Department of Public Health said in a statement to The Post on Thursday that 348 cases associated with mu had been reported in the state so far and that it would continue “to monitor all variants circulating in the state.”
Will my coronavirus vaccine work against mu?
It’s unclear how much protection the vaccines offer against this variant. “The Mu variant has a constellation of mutations that indicate potential properties of immune escape,” the WHO said in a statement Tuesday, raising concerns that it may be more resistant to coronavirus vaccines than other variants. “But this needs to be confirmed by further studies,” it added.