In its weekly epidemiological update, released on Tuesday, WHO warned that the Mu variant was growing more common in Colombia and Ecuador and that there were signs of probable vaccination resistance.

Mu was first detected in Colombia in January 2021, and there have been “sporadic reports” of cases and outbreaks in South America and Europe since then, according to WHO.

While the global frequency of Mu among sequenced COVID-19 cases is less than 0.1 percent, it has “consistently increased” in Colombia and Ecuador, where it currently accounts for around 39 and 13 percent of infections, respectively.

Given most nations' limited sequencing capability, reports on the occurrence of the variation should be "interpreted with great attention," according to the agency.

Mu is the fifth variant of interest that the WHO has been tracking since March. It contains a lot of alterations that suggest it may be more resistant to vaccinations, according to the health department, but further research is needed to prove this.

Preliminary findings suggest that vaccinations have a decreased efficacy "similar to that seen for the Beta variant." The WHO stated that it will be keeping an eye on “the epidemiology of the Mu variant in South America, particularly with the co-circulation of the Delta variant for changes.”

Nearly the last four weeks, over 4,500 sequences (3,794 B.1.621 sequences and 856 B.1.621.1 sequences), genome sequences, and tested samples of the virus obtained from patients have been classified as Mu. The sequences are used to trace how it travels across the population on GISAID, an open-source genome repository.

The majority of these have been recorded in the United States (2,065), Colombia (852), Mexico (357), and Spain (473).

Although this statistic is influenced by sequencing capacity, surveillance, and the overall number of cases in a given location.

According to a WHO study released on Wednesday, the new coronavirus pandemic has killed at least 124,811 individuals in Colombia.