The World Health Organisation says more research is needed on the omicron BA.2 subvariant and warns that it can be confused with other types of the virus in PCR tests to detect cases of COVID-19.
The omicron variant includes four lineages or subtypes. The one that has caused the latest wave of COVID-19 cases is BA.1 but BA.2 is on the rise in many countries, including India, South Africa, the UK and Denmark.
The epidemiologist leading the WHO’s response to COVID, Maria Van Kerkhove, explained on her Twitter account that BA.2 differs from the predominant subvariant in some proteins, including the herringbone protein.
“Research, both independent and comparative with BA.1, should be prioritised on the characteristics of BA.2, including its virulence and ability to evade vaccines,” Van Kerkhove said.
The WHO cautions that, unlike the predominant variant, BA.2 does not cause a specific marker in laboratory tests called “S-gene target failure”, which makes it resemble other coronavirus variants in a first screening. This does not mean that the variant cannot be detected, just that it is done differently.