Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, listens during a news conference in the James S. Brady Press Briefing Room at the White House in Washington, D.C., U.S., on Tuesday, April 13, 2021.
Leigh Vogel | Bloomberg | Getty Images
The new Covid-19 variant “mu” is not an immediate threat to the United States, federal health officials said Thursday.
“We’re paying attention to it, we take everything like that seriously, but we don’t consider it an immediate threat right now,” White House chief medical advisor Dr. Anthony Fauci said at a press briefing.
Mu — also known by scientists as B.1.621 — was added to the WHO’s list of variants “of interest” on Monday, the international health organization said in its weekly Covid epidemiological report published late Tuesday.
“This variant has a constellation of mutations that suggests that it would evade certain antibodies, not only monoclonal antibodies, but vaccine and convalescent serum induced antibodies,” Fauci said. “But there isn’t a lot of clinical data to suggest that, it is mostly laboratory in-vitro data.”
Even though Covid-19 vaccines were created with the original Covid strain in mind, the vaccines are still very effective against the delta strain.
“Remember, even when you have variants that do diminish somewhat the efficacy of vaccines, the vaccines still are quite effective against variants of that time,” Fauci said.
Delta was a variant of interest until the WHO reclassified it in early May after preliminary studies found it could spread more easily than other versions of the virus. That variant has since been blamed for a number of large outbreaks around the world, including in the United States.
The delta variant is still the dominant variant in the U.S., covering more than 99% of new infections in the country. The mu variant “isn’t even close to being dominant” in the U.S., Fauci said.
Mu was first identified in Colombia but has since been confirmed in at least 39 countries, according to the WHO. Although the global prevalence of the variant among sequenced cases has declined and is currently below 0.1%, its prevalence in Colombia and Ecuador has consistently increased, the agency warned.
“We’re keeping a very close eye on it,” Fauci said.