Last month the World Health Organization (WHO) designated Mu a "variant of interest." Now the strain has been detected in some 40 countries, including Finland.
The WHO homed in on Mu after reports that it has a "constellation of mutations that indicate potential properties of immune escape" that need to be studied further.
A Finnish virologist, however, said Mu most likely does not pose additional threats compared to other variants.
"All variants that can evade protection conferred by previous infection or vaccine-provided immunity are potentially worrying, or ones that we have to monitor—and that's the case with Mu as well," said Turku University virology professor Ilkka Julkunen.
The variant was first identified in Colombia earlier this year. A few Mu cases have been detected in Finland since the summer.
Julkunen noted that studies have indicated that two doses of a vaccine provide enough protection to prevent serious cases of Covid.
"More than 90 percent of fully vaccinated people don't develop serious infections, so in this sense vaccines provide ample protection against variants. It's very likely that this Mu variant is the same, so it doesn't suggest any substantial additional risk or worry compared to other mutations," he explained, adding that it was still too early to know how extensively this particular strain would spread.
The Delta variant of Covid-19, initially reported in India, remains the dominant mutation in Finland at the moment. It has been identified in 95 percent of the samples sent for sequencing during the past two months.
Finland currently performs genome sequencing on some 10-15 percent of positive samples.