On April 13, Beijing time, according to the real-time statistics of Johns Hopkins University in the United States, the number of confirmed covid-19 cases worldwide exceeded 500 million, and more than 6.1 million people unfortunately died of illness.
On 30 March, WHO Director-General Tedros Adhanom Ghebreyesus unveiled the updated Strategic Preparedness and Response Plan for COVID-19. "This is our third strategic plan for COVID-19 and probably should be our last." He said.
In the third year of the COVID-19 pandemic, Tedros listed three scenarios for the possible evolution of the outbreak.
Most likely, he said, while the virus continues to mutate, it will gradually reduce the severity of the disease it causes as immunity gained from vaccination and infection increases. When immunity is reduced, there may be a periodic spike in infections and deaths, which may require regular intensive vaccination of high-risk populations.
In the best case scenario, we may see less severe viral variants emerge without the need for a booster needle or a newly formulated vaccine.
But Tedros also warned that in the worst-case scenario, a more pathogenic and more transmissible variant might emerge sooner or later. In the face of this new threat, people's protection against severe illness and death, i.e. previous vaccinations or infections, "will rapidly wane."
On 11 April, WHO added the new sub-variants BA.4 and BA.5 of the Omiljung variant to the surveillance list. On March 30, the WHO also said that a recombinant strain known as XE was found in the Uk and had a 10 percent growth advantage over the currently dominant globally dominant Type Omikejong BA.2.
In either case, the most important factor determining the future direction of the COVID-19 pandemic is the evolution and mutation of the new crown virus itself. What is the next mutation of the new coronavirus after the latest global pandemic brought about by the Omi kerong mutation? Will it increase infectivity, immune evasion of vaccines and natural infections, and is it more pathogenic?
Even the most experienced scientists cannot make accurate predictions about these important questions, and the only certainty is that viruses will continue to evolve. All we can do is sum up the implications of the trajectory of virus evolution that has taken place over the past two years or so, and prepare as much as possible for the new mutations that are bound to come next.
Virus evolution changes the pandemic
When the number of confirmed cases in the world exceeded 100 million in early 2021, the report of the surging news (www.thepaper.cn) pointed out that the sudden change of the new crown virus is the most important and uncertain factor affecting the development of the epidemic.
All viruses mutate. The coronavirus has 30,000 bases (the basic unit of gene length), and each of its major variants evolved independently, rather than co-evolving with each other. So, basically we can't predict how the next strain will mutate, whether its infectivity and pathogenicity will be strong or weak.
For much of 2020, the strain of the new coronavirus that caused the coronavirus pandemic (SARS-CoV-2) accumulated mutations at a steady rate of twice a month on average, but most of the mutations had no substantial impact.
Other mutations, however, have brought about significant changes in the outbreak, and strains with these mutations have been classified by the World Health Organization as variants of concern (VOCs). The current VOC category includes alpha variants first detected in the UK, beta variants found in South Africa, gamma variants found in Brazil, Delta variants found in India, and The Omikejong variants found in Africa in November 2021.
Both delta and Omikejong mutations have triggered major changes in the trajectory of the global COVID-19 pandemic. Currently, Omilon's sub-variant, BA.2, dominates the global coronavirus, accounting for 94% of all genetic sequencing.
Compared to the original virus, the Delta and Omilon variants have greatly improved their ability to spread and their ability to evade vaccine protection. It can be said that the Omiljung variant BA.2 is already very different from the original strain in 2020.
However, the pace of evolution and mutation of the new crown virus has not stopped.
On 11 April, WHO added the new sub-variants BA.4 and BA.5 of the Omiljung variant to the surveillance list. On March 30, the WHO also said that a recombinant strain known as XE was found in the Uk and had a 10 percent growth advantage over the currently dominant globally dominant Type Omikejong BA.2.
The virus variant is of greatest concern: whether it will increase infectivity, immune protection from vaccine evasion and natural infection, and whether it is more pathogenic.
Jin Dongyan, a virology expert at the University of Hong Kong School of Medicine, pointed out to the surging news that overall, the evolution of the new crown virus will be like other known coronaviruses, the pathogenicity will be weakened, but at the same time, the spread will increase, making it more dominant.
"The power of transmission does not increase indefinitely, but there is an upper limit. Future evolution and variation will eventually stabilize. Jin Dongyan said.
Infectious and escape immunity of the main variants of the new coronavirus (the black dot in the lower left corner is the original strain in 2020)
What's next?
The emergence of Omiqueron has changed the perception of epidemic prevention in most countries in the world, and the effectiveness of existing vaccines to prevent infections has been greatly reduced. In the face of a virus with super infectious power and relatively low pathogenicity, preventing severe deaths, preventing hospitalization, and avoiding medical runs have become the main purposes of epidemic prevention.
What will be the next dominant mutant strain of COVID-19?
Danny Altmann, an immunologist at Imperial College London, told The Paper, "If there's one thing we've learned from COVID-19 research over the past 2 years, it's 'never say no' – that is, anything can happen." ”
"Think about it, we used to think it wouldn't spread from person to person, we thought it wouldn't spread through the air, and then we thought it was a moderately contagious lower respiratory virus. Now, we consider the BA.2 sub-variant to be one of the most contagious pathogens ever recorded, and it can easily infect the upper respiratory tract. Altman said.
For the prediction of the evolution of the new crown virus, the New York Times published an article jointly written by three virus evolution experts at the end of March this year, pointing out that although the number of infectivity of the new crown virus can still grow is an open question, the infectivity will not grow indefinitely. While we don't know when the coronavirus will reach a period of contagious stability, a period of stability will eventually occur.
Experts point out that now that people have acquired antibodies through vaccination or infection, antibodies can stop infection, so those variants that bypass antibodies will have a growing advantage.
Such is the case with the Omikejong mutant strain. With more than 50 mutations, Omikeron is more immune-evasive than any previous variant, and it reduces the ability of the antibody to recognize it. Studies have pointed out that by the end of 2021, when The Semikron becomes the dominant global strain, the protection of the third dose of vaccine is only 75%. This allows the mutant strain to spark a new wave of infections.
The above article points out that the new crown virus can infect people who have been vaccinated or people who have previously been infected with the new crown, and while it should not be surprising that it has evolved this ability, it is surprising how the Omilon variant has evolved this ability.
Because evolution usually proceeds in a gradual fashion, new successful variants are often derived from recent successful variants. That's why six months ago, many scientists thought the next variant would be derived from the Then dominant Delta variant.
However, the evolution of the new coronavirus has gone against the expectations of scientists - the Omikeron mutation has emerged, this mutation has a large number of new mutations, and from an evolutionary point of view, its ancestor is not Delta, but a completely separate new mutation.
"How Omikejong itself came about is still a mystery." Jin Dongyan, a virology expert at the University of Hong Kong School of Medicine, told The Paper.
From the perspective of virus evolution, The Omilon and the previous mutations are not related, although it is not clear how the huge evolutionary leap of the Omiljunn mutation was achieved, but Jin Dongyan said that many scientists speculate that the Omilkejong mutation may have appeared in those who cannot resist the virus well, and the virus has not been completely cleared from them for a long time and has been mutated.
Whether the next worthy variant will have more new features like Omilon or more typical gradual changes is unknown, but it is certain that the coronavirus will continue to evolve to escape immunity.
Will the coronavirus get weaker and weaker?
Finally, and most noteworthily, as the new crown virus continues to mutate, will the pathogenicity of the virus become weaker and weaker?
Altman told The Paper that most virologists are not strong supporters of the "getting weaker" view and believe that this is somewhat just the wishful thinking of some policymakers.
"For the common cold coronavirus, this (weakening) process spans hundreds of years. In a way, we are fooled by the fact that Aumequeron happens to be milder than TheRdalta, but the Opmiqueron did not evolve from Delta, but rather a fortuitous event among some chronically infected people in Africa. This reminds us that we don't know what other mutations are currently occurring among the tens of millions of infected people around the world. He said.
Whether the pathogenicity of the virus will become stronger is the most difficult to predict. The New York Times article argues that while evolution chooses a highly contagious virus, whether it will make the disease it causes more severe or less severe depends largely on luck.
"But we do know that immunization will reduce the severity of the disease, even if it does not completely stop the infection and spread of the virus, and in many countries, immunity gained through vaccination and previous infections has helped to weaken the wave of infection caused by the Omiljung variant." Newer or improved vaccines, as well as other measures to slow transmission, remain our best strategies for dealing with the uncertain future of virus evolution. The article said.
WHO also points out that no matter which direction the virus evolves and mutates in the future, the key response lies in vaccines and ensuring that they reach those most vulnerable to serious diseases. If the worst-case scenario arises — a more toxic and more transmissible variant — it would require drastic changes to current vaccines.
"I think we've had to learn a lot in some ways over the last two years or so: immunology, virology, vaccinology, public health. However, I have little confidence that we will do better next time after we have learned the lesson. My prediction for a pandemic is that we're going to spend 2 to 5 years hoping to have better vaccine immunity, reduce susceptible people, and therefore reduce cases. It will be a long and slow war of attrition. Altman said.
Are we ready for the new strains of the new coronavirus that are bound to appear in the future?