A new variant of COVID-19 that may be resistant to vaccines and other means of immunity, called “mu,” is likely already in Massachusetts, local doctors say.
The new mutation, called a “variant of interest” by the World Health Organization, has been detected in 49 states, with official cases reported in Illinois. The variant is not yet listed as supervised by U.S. health officials.
Three Boston-based doctors told NBC10 Boston where the variant came from, how it compares to the highly infectious delta variant, and what people should do to keep an eye on Massachusetts.
“It’s a variant of interest, of great interest, as it has now spread to many countries and almost every state in the United States,” Dr. Davidson Hamer of Boston Medical Center said Thursday. “The reason it’s of great interest is that it may be able to evade natural, vaccine-induced immunity. This has implications for reinfection, vaccine failure, and possibly monoclonal antibody treatments not working.” .
Originally from North South America, the variant has now also been detected in other countries, having been responsible for some clusters in England, explained Hamer and Dr. Daniel Kuritzkes, head of Brigham’s infectious diseases division and Women’s Hospital.
The variant contains genetic mutations that indicate natural immunity, current vaccines or monoclonal antibody treatments may not work as well against it as against the original ancestral virus, the WHO said. The strain needs further studies to confirm whether it will be more contagious, deadly or more resistant to current vaccines and treatments.
“It could be that the same mutations that make it difficult to neutralize a virus can also reduce a virus’s ability to transmit,” Kuritzkes said. “Over time we’ll only know for sure.”
The overall number of COVID cases has been increasing in Massachusetts and across the country as the highly infectious delta variant spreads, including those who are fully vaccinated.
“The delta variant is so contagious, that no other variant has been able to compete with it to dominate,” said Dr. Shira Doron of Tufts Medical Center. “The time to really look at the new variants is when the delta wave has receded.”
Delta remains the dominant strain in Massachusetts, with the latest data showing it accounts for 99% of cases, Kuritzkes said. But Boston-based doctors agreed that experts should continue to closely monitor the data to see if Mu takes over.
“It’s impossible to predict whether Mu will strengthen and become the predominant strain,” Kuritzkes said in an email Thursday.
“We need to keep a close eye on it to see if it displaces the delta,” Hamer added. “If the delta is more easily transmissible than mu, the delta may continue to predominate.”
The solution of the experts remains unchanged: global vaccination. Health experts continue to stress that vaccines reduce the risk of serious injury or death in exceptional cases. Until then, Doron said people should continue to practice standard coronavirus safety protocols.
“The same precautions you take now to avoid the delta variant will be important to avoid mu and any other emerging variant,” Doron said, noting that the virus is always mutating. “And even a variant that has immune evasion activity is likely to see some serious soiling through vaccination, so get vaccinated if you haven’t already and get your second dose if you’ve only had one dose of mRNA vaccine “.