The Mu variant is on the rise. Scientists weigh in on how much to worry.
Laboratory studies suggest this variant may be better at avoiding the immune system but lags Delta when it comes to transmission and infecting cells.
One of the newest variants of COVID-19, known as Mu, has spread to 42 countries, but early studies suggest that it is less easily transmitted than the dangerous Delta variant, which has triggered a resurgence of the pandemic in the U.S. and many other countries.
Mu quickly became the dominant strain in Colombia, where it was first detected in January, but in the U.S., where the Delta virus is dominant, it has not spread significantly. After reaching a peak at the end of June, the prevalence of the Mu variant in the U.S. has steadily declined.
Scientists believe that the new variant cannot compete with the Delta variant, which is highly contagious.
