Natural Immunity less powerful against new Omicron strains in South Africa as Fifth Wave looms

By Dana Malcolm

Staff Writer

#Africa, May 19, 2022 – South Africa is undergoing a massive covid surge with cases jumping by 50 percent in just 24 hours on May 5th. 9,757 new cases were reported on the 5th, 3,587 more positive results than the 6,170 recorded the day before.  For context, on April 5th, a month earlier 1538 new infections were recorded.

Since that 50 percent increase on May 5th daily new infections have consistently been above 2,900 reaching as high as 10,017 on May 11th. South Africa recorded over 86,000 new cases and over 550 deaths between May 5th and 16th in a time frame of less than 2 weeks.

Vaccine uptake in South Africa is below slightly above 50 percent with only 35 million fully vaccinated individuals in a population of more than 59 million.

Shabir Mahdi, a scientist leading vaccine trials in the country had suggested that natural immunity was what was helping with lower hospitalizations when omicron initially appeared in the country.

This latest increase however, is being driven by the BA.4 and BA.5 Omicron sub variants, which may be more adept at evading natural immunity.

In a study carried out by the Africa Health Research Institute blood samples from people infected with omicron but unvaccinated, when tested against BA.4 and BA.5, neutralizing antibodies which fight Covid were eight times lower. In people who contracted omicron and were vaccinated it was three times lower.

The study has not yet been peer reviewed but the researchers say, “The low absolute neutralization levels for BA.4 and BA.5, particularly in the unvaccinated group, are unlikely to protect well against symptomatic infection,”

“This may indicate that… BA.4 and BA.5 have potential to result in a new infection wave.”

That study was carried out back in January when the variants were first detected.

When the Omicron fueled fourth wave hit South Africa in 2021 cases in the United States, Canada and parts of Europe quickly followed. BA.4 and .5 have been detected in the US, Canada, China and parts of Europe.

On May 12th the BA.4 and.5 variants were both upgraded to variants of concern by the European Centre for Disease Control.

The ECDC says variants of concern are ones for which, “clear evidence is available indicating a significant impact on transmissibility, severity and/or immunity that is likely to have an impact on the epidemiological situation in the EU/EEA.”

The possible spike in cases comes one year and five months since the first COVID jabs in the world were administered in the UK and the US,  one year and four months since the first vaccine was administered in the Turks and Caicos.

Though boosters have been available in many countries worldwide booster campaigns have not been as effective as initial vaccination campaigns. Without the stretched protection of boosters many more people may remain vulnerable to this building wave of BA.4 or BA.5 vaccines.