Omicron BA.4 & BA.5 Likely To Evade Vaccines, Natural Immunity: Study

Johannesburg: There are fears of a fifth COVID-19 wave in South Africa earlier than expected, driven by the BA.4 and BA.5 sub-variants of Omicron.

There has been a sustained rise in infections over the last fortnight. Hospitalizations have picked up, though there was no dramatic change in admissions to intensive care units or deaths, Health Minister Joe Phaahla said.

However, an expert said that the new sub-lineages (BA.4 and BA.5) will evade coronavirus vaccines and natural immunity from prior infections.

A study by South Africa’s head of gene sequencing units Tulio de Oliveira found that the two new strains appear to be more infectious than the BA.2 lineage, which was more infectious than the original Omicron variant.

“Our main scenario for Omicron BA.4 and BA.5 is that it increases infections but that does not translate into large hospitalizations and deaths,” Oliveira tweeted.

Oliveira, who heads the Centre for Epidemic Response & Innovation (CERI), said that BA.4 and BA.5 are distinct from other Omicron lineages and are estimated to have originated around mid-December and early January.

The epidemiologist said the rapid increase in COVID-positive cases in the last two weeks was caused by BA.4 and BA.5.

“The 6,000 infections yesterday are underestimated as the test positivity ratio is around 20%. SA (South Africa) did not have a BA.2 Omicron wave-like Europe but only a large BA.1 wave,” he tweeted.