Despite 97% Population Antibody Possession, COVID-19 Resurgence in South Africa... "Infectivity Especially High"

BA.4·BA.5, Infection Possible Even in Individuals with Antibodies Formed

A woman is receiving the COVID-19 Pfizer vaccine in the Diepsloot township near Johannesburg, South Africa. / Photo by AP Yonhap News

[Asia Economy Reporter Na Ye-eun] Despite an estimated 97% of South Africa's population having COVID-19 antibodies, a study has found that the country is experiencing a resurgence due to the Omicron variant.

According to Bloomberg on the 30th (local time), blood samples from 3,395 South Africans tested earlier this year showed that 87% had been infected with COVID-19.

Additionally, the proportion of people who either had a history of COVID-19 infection or had received at least one vaccine dose and thus possessed antibodies exceeded 97%.

However, South Africa has recently seen a sharp increase in confirmed cases, leading to assessments that the country has entered a fifth wave.

The study, led by the DST-NRF Centre of Excellence in Epidemiological Modelling and Analysis at Stellenbosch University and the South African National Blood Service, shows that the Omicron variant, particularly its subvariants BA.4 and BA.5, have the ability to infect people who already have antibodies.

In fact, the seven-day average of confirmed cases in South Africa was 1,307 on the 16th of last month but surged more than fivefold within a month, with a significant increase in the prevalence of BA.4 and BA.5 reported.

However, even when the recent surge in infections peaked and the positivity rate approached record highs, the rate of hospitalizations due to severe illness was lower than in previous waves, and relatively fewer deaths were reported.

The researchers explained, "The infectivity of the Omicron variant is exceptionally high, which caused such a significant outbreak even at this relatively mature stage of the epidemic."

South Africa, the hardest-hit country in Africa by COVID-19, has officially recorded over 100,000 related deaths. However, considering excess mortality?which analyzes how many more people died than usual?the figure is estimated to be more than three times higher.

Meanwhile, the Omicron variant and its subvariants BA.4 and BA.5 were first identified in southern Africa. In South Africa, half of the 40 million adults have been vaccinated against COVID-19.