Almost half of Covid-19 survivors may still be vulnerable to SA variant: scientists

 

Some Covid-19 survivors could still be vulnerable to reinfection, should they contract the South African variant, scientists have warned.

The mutation, called E484K, has the capability to slip past parts of the immune system in as many as half of people infected in the past, scientists fear.

The team of South African researchers on Monday said that the particular change on a specific part of the virus' outer spike protein appears to make it able to ''escape'' antibodies. 

Antibodies are proteins that the body produces to elicit an immune response against a foreign substance in the body.

The mutated and more infectious coronavirus has now spread to 12 other countries.

‘Alarming’ mutation

Penny Moore, Associate Professor at the National Institute for Communicable Diseases in South Africa, said the mutation is “alarming.”

“We fear this mutation might have an impact, and what we don't know is the extent of the impact,” she said.

The scientists, led by South African epidemiologist and infectious diseases specialist Prof Salim Karim, found that 48 percent of blood samples from people who had been infected in the past did not show an immune response to the new variant.

The team also said that it is still unknown if the vaccines developed against the virus are effective on the 501Y.V2 variant.

“There’s much to speculate on but we are expecting an answer pretty soon. We want to see the actual data which is currently not available,” said Prof Karim.

This could raise worry for countries like Kenya which have managed to reduce the number of infections, almost flattening the curve as per the World Health Organisation’s recommendations.

Silent spread

Already, there is concern that the two strains (first reported in the United Kingdom and South Africa as B.1.1.7/501Y.V1 and B.1.315/501Y.V2) could be spreading silently in the Kenyan population though they are yet to be identified.

But also, Kenyan scientists have fears that a variant unique to the country has already caused quite a significant number of infections in Taita-Taveta County, a phenomenon that could be extrapolated to other counties.

“Given that Mombasa and Nairobi are major ports of entry, our hypotheses, if we carried out larger sequencing, we are likely to find D80A variants in other counties,” Dr Charles Agoti, a Kemri researcher, said.

However, Dr Agoti, a principal member of the team of investigators that reported the findings on Tuesday evening, said the vast majority of mutations are often insignificant and have little impact.

United Kingdom

Countries have been pulling all stops to control the new variant. For instance, the United Kingdom has now made it mandatory for all international arrivals to quarantine for 10 days and provide proof of a negative test within three days before departing for the UK.

In East Africa, Rwanda introduced a 15-day total lockdown for its capital city, Kigali, on Monday amid rising cases.

The country's aviation hub, Kigali International Airport, will, however, remain open, according to a communique from the office of the Prime Minister.

Prior to the mutation, the area where the 484 were sitting on the human cell were both negatively charged and repelling from each other, making it difficult for the virus to stick properly to the cell, Prof Karim explained during a virtual webinar held on Monday.

Outsmart antibodies

When the mutation occurred, he added, 484 became positively charged, meaning if the virus came close to a human cell it was able to attach.

This binding affinity has given the virus ability to outsmart antibodies. This 484 enables the virus to escape the body’s existing immunity.

A recent study showed that in 44 South Africans infected in the first wave, over 90 percent had lower immunity against the virus during the second wave and almost half (48 percent) had none at all for the mutated virus.

So, will wearing of masks and maintaining social distance work for the variant? “Yes, the new variant is as sensitive to such public health measures as the old variant. That’s why it’s so important that we continue with these measures,” said Prof Moore.