Are New Omicron Subvariants a Threat? How Scientists are Keeping Watch

Two new members of the Omicron family of coronaviruses are described by the man sitting in the garden. In South Africa, the subvariants called BA.4 and BA.5 are growing in prevalence.

The World Health Organization is interested in the viruses because they might be able to evade immunity gained from COVID-19 vaccines or prior infections more strongly than existing versions of Omicron. He is clear that he isn't panicked by BA.4 and BA.5. Although the subvariants have gained ground in South Africa, the rates of COVID-19 cases and hospitalizations are stable. He is unruffled because he has been through this before and his team knows the drill. He says it's just time to work carefully and calmly.

Scientists are studying these subvariants to see if they are serious enough to warrant intervention. Not every variant of SARS-CoV-2 will be news. Wendy Barclay, a researcher at Imperial College London, says that researchers focus on two factors, the severity of the disease and the variant that evades vaccines.

While not provoking unnecessary government policies and anxiety, researchers are grappling with how to communicate their concerns and uncertainty openly. The United States and the United Kingdom imposed travel bans against South Africa after de Oliveira's team detected the original Omicron. The South African economy was badly damaged by the bans. I would stop sharing data in real-time with the world, but would continue sharing with my government, to guide our own response, if that happens again, says de Oliveira.

The new variants

On 1 April, a bioinformatician on de Oliveira's team at Stellenbosch saw that researchers at the National Institute for Communicable Diseases in South Africa had flagged several abnormal SARS-CoV-2 genome sequences. There are a few notable changes in the region of SARS-CoV-2 that are contained in the sequence. Because the spike protein is key to the virus invading cells, the need to find the missing pieces in the country's genomes was urgent.

He and his colleagues found out that they had. The BA.4 and BA.5 sequence made up around 5% of the roughly 500 genomes in South Africa during the first week of March. The portion had risen to 50% by the first week of April. The Omicron family tree was determined to have separate lineages of BA.4 and BA.5 by an international virus classification group.

In the past two weeks, a small number of BA.4 and BA.5 sequences have been uploaded to the data platform, as well as the accumulating sequence from South Africa.

One thing that makes BA.4 and BA.5 stand out is their similarity to F486V. It is located on the viruses near where the spike is located, which opens the door to infections. This spot is where important antibodies were created in response to COVID-19 vaccines and prior infections with the coronaviruses.

The vulnerability of this spot in laboratory experiments was noticed last year. Benhur Lee and his colleagues at the Icahn School of Medicine at Mount Sinai in New York City were helping to vet a promising monoclonal antibody treatment by exposing it to an artificial virus carrying many versions of the SARS-CoV-2 spike protein. Only one version of the spike was able to evade their antibodies. It was nearly identical to F486V.

At the time, Lee was relieved that the mutation was rare in real life, and that it might have hampered the virus. Lee was reassured that the treatment would still be useful despite the fact that only 50 of the 10 million sequence contained the mutation. Lee explains that the coronaviruses has evolved so that it no longer holds back, thanks to the rapid rise of BA.4 and BA.5 in South Africa.

Risk analysis

Lorenzo Subissi says the WHO is following the two sub-lineages. It needs to learn more from epidemiological studies of people before drawing a conclusion about whether they pose an additional threat. The question of immune escape is being explored by exposing samples of BA.4 and BA.5 to blood from people who have been exposed to the disease.

We immediately gave samples to researchers around the world. Researchers in South Africa, the United Kingdom, and the US National Institute of Health were included.

After identifying BA.4 and BA.5 he met with the South African government and a group of 200 researchers. He advised the government not to set stricter guidances than the country already has because there has been no increase in hospitalizations. The government has not changed its rules.

De Oliveira was careful with the information he gave to health officials from other countries, asking them to keep an eye on the news and not to use travel bans that can cause more harm than good. There was security in front of the lab.

In the face of such tensions, Barclay applauds the work of South Africa. She says that the less severe version of the coronaviruses is not a sign that it will become weaker. In addition to acquiring normal changes, the SARS-CoV-2 can evolve rapidly through the process of recombination, which inserts one chunk of a sequence from a variant into the genome of another. If an Omicron variant recombines with a different one, it could produce a virus that makes people sicker.

The Pulitzer Center supported the story.

The article was first published on April 15 2022.