Europe puts two Omicron sub-lines on worrying list

Europe is seeing a rapid increase in COVID-19 cases due to the Omicron variant subline – Photo: BLOOMBERG

In a statement posted on its website May 13, the ECDC explained that the decision to put BA.4 and BA.5 from the Variant of Concern (VOI) list to the Variant of Concern (VOC) list came from actually observed in Portugal in recent weeks.

The Portuguese National Institute of Health estimates that BA.5 has accounted for about 37% of positive cases as of May 8. On a daily basis, the number of infections with this sub-lineage increased about 13% faster than the BA.2 line. Assuming this growth continues, BA.5 will become the dominant variant in Portugal on May 22.

According to the ECDC, the fact that BA.4 and BA.5 have a higher transmission rate than other sub-lines of Omicron This may be because they evade the body’s immunity formed by having had COVID-19 or being vaccinated.

Available but limited data from serological studies of unvaccinated and former BA.1-infected individuals suggest that both BA.4 and BA.5 have the potential to escape immunity conferred by BA.1 infection.

However, according to the ECDC, with current data, the BA.4 and BA.5 sublines did not cause more severe disease than the previous sublines.

Even so, the emergence of these two sub-lines could push the number of COVID-19 cases in Europe to skyrocket in the next few weeks or months. And just like in previous episodes, if the number of COVID-19 cases increases significantly, the number of hospitalizations and ICUs will increase accordingly, according to the ECDC.

On that basis, the agency suggested that countries should be wary of two sub-lines of Omicron, continue to vaccinate and take representative test samples to understand the evolution of the virus.

BA.4 and BA.5 were first recorded in South Africa in January and February 2022. On May 11, the World Health Organization (WHO) made an initial assessment of the BA.4 and BA.5 sublines.

According to WHO Technical Team Leader on COVID-19, Maria Van Kerkhove, about 700 infections of the BA.4 subline have been detected in at least 16 countries and 300 cases of BA.5 have been detected in at least 17 nation.

While these two subtypes are no more dangerous than the other strains of Omicron, they spread more quickly. WHO is still closely monitoring BA.4 and BA.5 to determine whether these two sublines can overtake BA.2 to become the world’s dominant pathogen.