The WHO added PE4 and PE5 substrains of the original Omicron PE1 strain to its watchlist. It already tracks the two strains PE1 and PE2 that are currently prevalent worldwide, as well as PE1.1 and PE3.
The organization explained that they have begun monitoring them because of “additional mutations that need to be studied further to understand their impact on the ability to overcome immunity.”
Viruses continue to mutate, but very few mutations affect their ability to spread or overcome immunity acquired through vaccination, previous infection, or the severity of the disease it causes.
For example, PE2 currently accounts for nearly 94 percent of all consecutive cases and is more likely to spread than other Omicron substrains, but evidence so far suggests that it is unlikely to cause serious illness.
The World Health Organization reports that only a few dozen cases of PE4 and PE5 have been identified in the global database.
And the British Health Safety Agency said last week that substrain (PE4) had been detected in South Africa, Denmark, Botswana, Scotland and England from January 10 to March 30.
