There is a new virus! COVID-19 mutates every 6 months? Beware of Delta's comeback
Omicron also sees new subtypes BA.4 and BA.5, which may change the rules of the game?
While local cases in Taiwan have surged by tens of thousands in recent days, the evolution of the COVID-19 virus has not stopped. The international authoritative journal “Nature” published a report stating that South African science discovered two subtypes of BA.4 and BA.5 again about 6 months after the emergence of the previous generation of Omicron mutant strains, and the transmissibility of these two mutant beads was The earlier version of Omicron had the potential to be a “game changer.”
Penny Moore, a virologist at the University of the Witwatersrand, pointed out in the report that the epidemic in South Africa is indeed resurgent, and this wave of epidemics is caused by two subtype variants, BA.4 and BA.5. promoted. Moore even said that in his laboratory alone, 6 people were infected by the new virus variant and were diagnosed.
However, BA.4 and BA.5 have not yet caused a significant increase in the number of hospitalizations in South Africa and other regions. One possible reason is that the protection provided by previous Omicron infections and vaccines has weakened the damage to human health caused by the new mutant strains. But Tulio de Oliveira, a bioinformatician at Universiteit van Stellenbosch, warned that compared with the pandemic of the previous two years, the evolution direction of the virus seems to be different, and Omicron seems to continue in a cyclical pattern. New virus strains mutate.
After analyzing the genetic lineage of the virus, Oliveira pointed out that the two subtypes BA.4 and BA.5 first appeared in December 2021 and January 2022. They have now caused nearly 5,000 confirmed cases per day in South Africa, and the spread rate is faster than that of BA. The .2 mutant strain is faster. This study has been published in a preprint and has not yet passed peer review.
F486V key mutation point virus can re-infect confirmed patients
Tom Wenseleers, an evolutionary biologist at the Catholic University of Leuven in Belgium, believes that increased transmissibility is a considerable advantage of the new coronavirus. Judging from the current data, the new Omicron variant seems likely to cause another considerable wave of infection peaks. .
Jesse Bloom, a viral evolutionary biologist at the Seattle Research Center in Washington, agrees. The BA.4 and BA.5 subtypes appear to be more transmissible and better able to evade antibodies and immune responses, allowing people who have been infected to become reinfected.
Bloom pointed out that the mutations of BA.4 and BA.5 are closely related to BA.2. Both of them have the key mutation point “F486V” found in the S protein. This protein is closely related to infection and immune response, which may allow Variants are able to evade antibodies. In any case, what is certain is that the number of infections with the two subtypes BA.4 and BA.5 is increasing, and in a group analysis, 15 of the 39 confirmed cases had been vaccinated.
Although BA.4 and BA.5 have stronger infection capabilities, the threat of escaping immunity is not significant. This alone may cause a new wave of epidemics. Bloom believes it is unlikely that either subtype will cause a higher proportion of severe cases than previous strains, especially in people who have been vaccinated. However, due to its immune escape advantage, it may still spread again in areas where there has been a pandemic like South Africa.
Mutation every six months? Scientists warn: Delta may be making a comeback
Mutated strains such as BA.4 and BA.5 have been successively detected in North America, Europe and other places, but local people may have only been infected with COVID-19 once and still have a certain degree of immunity. Penny Moore believes that if the COVID-19 virus evolves in this direction, it may eventually evolve into something similar to other respiratory viruses such as influenza, and the immune evasion ability of “circulating mutant strains” like Omicron virus will continue to produce new ones due to their combination with human immunity. Periodic infections were diagnosed.
“Nature” stated that Alpha, Delta and Omicron are already significantly different from the original SARS-CoV-2, and it cannot be ruled out that more mutant strains will bring “surprises” in the future. In addition, the Delta mutant strain has not completely disappeared.
As resistance to Omicron continues to rise in the global population, it is possible that descendant subtypes of Delta will make a comeback. Scientists such as Wenseleers believe that new highly contagious mutant strains of the virus, which appear to appear every 6 months, will require in-depth study of whether COVID-19 will move toward a cyclical transmission structure.
However, Jesse Bloom reminded that the virus transmission model observed at this stage is only one of the possibilities. From the emergence of the COVID-19 virus to the present, scientists’ research observations on the virus are still short-lived, and all estimated conclusions should be more cautious.
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Are COVID surges becoming more predictable? New Omicron variants offer a hint
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