Two strains of Omicron from South Africa are labelled ‘variants of concern’ by European health officials

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Two strains of Omicron have been labelled “variants of concern” that could dominate this summer, health officials warned.

The European Centre for Disease Prevention and Control (ECDC) said in a report that variants BA.4 and BA.5 could lead to soaring Covid cases across the continent risking additional pressures on hospitals and ICU departments in a matter of weeks and months. It added that countries should remain vigilant for signs that new variants are emerging.

The warning comes as nations across the continent attempt to live with minimal restrictions and enjoy summer holidays across Europe. ECDC also advised that people over 80 should “immediately” go forward for a second Covid booster jab, adding that countries should plan for over 60s and other vulnerable groups to receive a second booster.

Both BA.4 and BA.5 were first detected in South Africa in January and February 2022, respectively, and since then they have become the dominant variants there, the report warned. The currently observed growth advantage for BA.4 and BA.5 is likely due to its ability to evade immune protection induced by prior infection or vaccination.

The Portuguese National Institute of Health estimated that BA.5 already accounted for over a third (37 per cent) of positive cases in the nation as of 8 May 2022. The estimated daily growth advantage for BA.5 over the formerly dominant variant BA.2 is 13 per cent, which is similar to the 12 per cent daily growth advantage previously reported by South Africa. Assuming such growth rate, BA.5 will become the dominant variant in Portugal in under a week.

However the report said there was currently “no indication of any change in severity for B.A4/BA.5 compared to previous Omicron lineages”.

“The presence of these variants could cause a significant overall increase in Covid-19 cases in the EU/EEA in the coming weeks and months,” the ECDC said.

“The overall proportion of BA.4 and BA.5 in the EU/EEA is currently low but the high growth advantages reported suggest that these variants will become dominant in the EU/EEA in the coming months.

“However, as in previous waves, if Covid-19 case numbers increase substantially, some level of increased hospital and ICU admissions is likely to follow. ECDC encourages countries to remain vigilant for signals of BA.4 and BA.5 emergence.”

It added: “For all age groups, it remains a priority to improve Covid-19 vaccine uptake of the primary course and first booster dose in populations who have yet to receive them.”

The Office for National Statistics (ONS) estimates 1.2 million, or one in 45 people in England, were carrying the virus on any given day in the week to 7 May, down a quarter on the previous week.

It marks the fifth week in a row that the ONS’ weekly infection survey has reported a week-on-week fall in cases.