Two new Covid strains have been upgraded to ‘variants of concern’ amid signs that they can evade immune protection and can even reinfect people who have already had Omicron.
Known as BA.4 and BA.5, the variants 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 designated a ‘variant of concern’.
Yahoo News reports: 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.
Scottish Government epidemiologists previously warned that holidaymakers returning from abroad this summer were likely to seed a new Covid wave.
The European Centre for Disease Prevention and Control (ECDC), which upgraded BA.4 and BA.5 from variants under investigation (VUI) to variants of concern (VoC) late on Friday, said preliminary studies “show a significant change in antigenic [immune response] properties of BA.4 and BA.5 compared to BA.1 and BA.2, especially compared to BA.1”.