TWO new Covid strains have been designated as ‘variants of concern’ amid signs that they can dodge immune protection, including reinfecting people who previously had Omicron infections.
The variants – known as BA.4 and BA.5 – were first detected in South Africa in January and February respectively, and have since become the dominant strains in the country.
It is the first time since Omicron emerged at the end of November that a new Covid variant has been classified as a variant of concern.
According to the World Health Organisation, BA.4 has been detected in at least 16 countries and BA.5 in 17 countries. Both have been identified in small numbers in the UK.
BA.5 has been making up an increased proportion of cases in Portugal in recent weeks, with the Portuguese National Institute of Health estimating that the strain already accounted for approximately 37% of positive cases by May 8. It is expected to become Portugal’s dominant variant by May 22.
