Over half of COVID-19 infected adults in S Africa are asymptomatic: Official

The deadly contagion, which first emerged in China's Wuhan city in December last year, has claimed 3,860 lives and infected over 2,50,000 people in South Africa. “The majority of COVID-19 infections are going unnoticed,” according to Dr Shabir Madhi, the leader of the South African leg of an international vaccine trial headed by the University of Oxford.

A top health official in South Africa has said that about 50 to 66 per cent of all the adults infected with the COVID-19 disease in the country are asymptomatic, with many infections going undetected. The deadly contagion, which first emerged in China's Wuhan city in December last year, has claimed 3,860 lives and infected over 2,50,000 people in South Africa.

“The majority of COVID-19 infections are going unnoticed,” according to Dr Shabir Madhi, the leader of the South African leg of an international vaccine trial headed by the University of Oxford. In an interview with CNBC on Friday, Madhi said that the high number of asymptomatic cases was causing difficulties in vaccine trials.

The enrolment process has shown that far more people are asymptomatic than what was previously believed, he said. He estimated that only about 10 per cent of all COVID-19 cases are being officially reported.

Madhi said around 80 per cent of all children who are infected are asymptomatic. The clinical trials require people who have not been infected by the virus. Part of the enrolment process for the COVID-19 vaccine trial involves the screening of individuals.

Qualifying participants are randomly allocated into one of two groups -- vaccine group or placebo group. Madhi said the results on whether the vaccine works as protection against COVID-19 would be available by the end of November this year, but the trials may be extended into the second quarter of next year.

He warned against the undue optimism, reminding that only 10 per cent of vaccines that go into clinical trials are eventually licensed for use. “Right now there are approximately 200 vaccines that are being developed (around the world) for the COVID-19.

“It would be a huge accomplishment if, over the next 12 to 18 months, we are successful in showing that even one out of every 20 of the vaccines that go into human studies are safe and provide some protection against COVID-19,” Madhi said. He said for the next year at least, the only reliable protection against the COVID-19 disease would be the non-pharmaceutical interventions of handwashing, sanitisation and social distancing.

According to Johns Hopkins Coronavirus Resource Center, the contagion has infected over 12 million people and killed more than 560,000 across the world. The COVID-19 has also battered the world economy with the International Monetary Fund saying that the global economy is bound to suffer a "severe recession".

Scientists are racing against time to find a vaccine or medicine for its treatment..