The European Centre for Disease Prevention and Control (ECDC) has announced through its latest update that it has decided to reclassify Omicron sub-lineages BA.4 and BA.5 from variants of interest to variants of concern.
According to ECDC, BA.4 and BA.5 were first detected in South Africa earlier this year, and since then, they have become the dominant variants there.
In addition, the same reveals that an increasing trend in the variant proportions for BA.5 has been observed in Portugal in the recent weeks, accompanied by an increase in COVID-19 case numbers and test positivity rate, SchengenVisaInfo reports.
The National Institute of Portugal has estimated that BA.5 already accounted for around 37 per cent of the positive cases as of May 8, 2022.
The estimated growth advantage for BA.5 over BA.2 is 13 per cent, meaning that it is similar to the 12 per cent daily growth advantage that was previously reported by South Africa. Assuming the same growth rate, BA.5 will become the dominant variant in Portugal by May 22.
ECDC emphasises that the growth advantage for BA.4 and BA.5 is likely due to their ability to evade immune protection induced by prior infection and vaccination.
“Limited available data from in vitro studies evaluating sera from unvaccinated individuals who have experienced a prior BA.1 infection indicate that both BA.4 and BA.5 are capable of escaping immune protection induced by infection with BA.1,” the statement of ECDC reads.
This suggests that unvaccinated individuals are unlikely to be protected against infection with BA.4 and BA.5.
As for the severity, it has been highlighted that currently, there is no indication of any change in severity for BA.4 and BA.5 compared to the previous Omicron lineages.
ECDC explains that the presence of these variants could cause a significant overall increase in the COVID-19 cases in the European Union/European Economic Area in the coming weeks and months.
Currently, the overall proportion of BA.4 and BA.5 in the EU/EEA is low, but the high growth advantages that have been reported suggest that these variants will become dominants in the EU/EEA in the next months.
Taking into account such trends, ECDC encourages the EU/EEA countries to remain attentive to signals of BA.4 and BA.5 development.
“Early variant detection critically relies on sensitive and representative testing and genomic surveillance, with timely sequence reporting,” ECDC highlights.
In addition, the same noted that for all age groups, it remains a priority to improve the COVID-19 vaccine uptake for the primary course and first booster dose.
The EU/EEA countries administered a total of 885,756,407 vaccine doses as of May 12. The data shows that 72.6 per cent of the entire population in the EU/EEA has completed primary vaccination, and another 51.7 per cent has received a booster shot.