Experts hypothesize that Omicron mutated from animals, developed in immunocompromised humans, or formed in an area where there is little genetic sequencing.
Since the appearance of the Omicron variant, scientists have been rushing to find answers to a series of questions: how the virus develops, how it is transmitted, and how severe the symptoms are compared to the Delta variant. Associate Professor Darren Martin, a researcher at the Institute of Infectious Diseases and Molecular Medicine at the University of Cape Town, thinks that the viral proteins work together and create mutations in the S gene. This change makes nCoV contagious. infection more effectively.
The team also put forward three hypotheses about the evolution of Omicron.
The first, mutations that form in an area where viral genetics are rarely sequenced, people have limited access to health care services. This means that Omicron has been circulating in South Africa or some other country for a long time without being detected. South Africa is currently sequencing only 1% of the samples collected, while in the US the figure is 3.6%. No country in Africa has decoded more than 5,000 viral genetic samples.
In fact, some evolutionary biologists also suggest that the Omicron variant has been present since September and spread for several months. But this is just a theory.
The Dutch Ministry of Health said on November 30 that the Omicron strain may have appeared in the country at least 10 days before the report from South Africa. This is evidence that the mutation reached Europe earlier than is known.
Previously, according to the global GISAID database, the first Omicron infections in South Africa, sampled on 9/11, were two men in Johannesburg. By 11/11, the mutation spread to Botswana. On November 26, South Africa issued a warning about Omicron.
The second hypothesis is nCoV exists in immunocompromised people (such as HIV patients) for a long time, from there mutating into Omicron. This is what South African experts have feared since the beginning of the pandemic.
When HIV patients take their prescribed antiretroviral drugs on a regular basis, their bodies almost completely block the virus. But in people who are undiagnosed, untreated, or unable to take their daily medication, HIV weakens the immune system. If they have Covid-19, it takes their body weeks or months to get rid of the virus. During that long time, nCoV has a chance to mutate. When a patient with an underlying HIV disease spreads Covid-19 to others, new strains multiply and circulate.
“We have reason to believe that some of the strains emerging in South Africa are directly related to HIV,” said Tulio de Oliveira, principal investigator with the National Genetic Surveillance Network.
The final hypothesis is nCoV re-infected animal populations, then mutated and re-infected humans. Kristian Andersen, an immunologist at the Scripps Research Institute, said: “It’s reasonable to expect the mutation to come from immunocompromised humans, but really, I believe in the ability of the virus to spread back from humans to animals. , evolved and then passed on to humans, because some of the mutations in the virus are very unusual. I don’t think we should rule out that scenario.”
Scientists support this hypothesis based on a number of properties of nCoV. This is a fairly versatile virus, capable of infecting many animals such as dogs, cats, tigers, ferrets, white-tailed deer and even humans. Therefore, nCoV easily “jumps” from one species to another. The virus that originally came from Wuhan did not infect rodents. But later mutations such as Alpha, Beta, Delta appeared in this animal.
The World Health Organization (WHO) and health experts have repeatedly warned that the inequality in vaccines and the inability of some countries to cope with the disease is easy for many strains to appear. To date, less than 7% of the 1.2 billion people in Africa are not fully immunized. The East African country of Eritrea does not yet have a vaccine.
Professor Martin’s team said: ‘Our new finding requires more results to conclude which hypothesis is correct.
Thuc Linh (Follow News NPR, Stat News)