Jin Dongyan: New coronavirus mutation rate is much lower than influenza, "global epidemic is coming to an end"

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Jin Dongyan said, “The emergence of Omicron is the immune escape at the cost of much weaker pathogenicity, but this does not mean that boosting immunity is useless, on the contrary, for fighting the virus, vaccination is one of the very important efforts. For the development of the epidemic, I speculate that the global new crown epidemic is coming to an end, as long as no new variant with super-immunity or super-pathogenicity emerges.”

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“I want to clear up a misconception here, after a previous media interview in which I said that omicron might be more likely to attack those with strong immunity, many people made a big deal about it and claimed that boosting immunity was useless and that vaccination would be counterproductive. That’s actually not true.” On the evening of Dec. 22, Professor Jin Dongyan, a virologist and professor at the School of Biomedical Sciences, The University of Hong Kong Li Ka Shing Faculty of Medicine, said reluctantly during a presentation on the theme of “Domestic and international initiatives and rationale for the new crown vaccine” at the “Future Lecture Hall” online conference.

“What I mean is that the general trend in the emergence of new variants of Neoplastic viruses is the increase of transmission and immune escape and the decrease of pathogenicity. The emergence of Omicron is to achieve immune escape at the cost of much weaker pathogenicity, weak pathogenicity is its inherent characteristic, and the new variants that emerge in the future will probably not escape this framework. But this does not mean that strengthening immunity is useless, on the contrary, vaccination is a very important part of the work to resist the virus.” Jin Dongyan explained.

As for the future mutation of the new crown virus, Jin Dongyan said, “The mutation rate of the new crown virus is actually much lower than the mutation rate of the influenza virus and SARS virus, it is only about 1/4 of the mutation rate of the AIDS virus. i speculate that the global new crown epidemic is coming to an end as long as there are no new variants that are super immune or super pathogenic.”

He draws an analogy to influenza viruses, which mutate in two ways: antigenic switch and antigenic drift. Antigenic switch refers to the reassignment of segments of the viral genome when cells are infected with two different subtypes of influenza viruses. The antigen is substantially mutated and is a qualitative change, often resulting in new subtypes that can easily cause pandemics and are more difficult to prevent.

Antigenic drift, on the other hand, refers to small or continuous mutations of the virus, which are quantitative, i.e., intra-subtype variation. This variation is generally considered to be caused by viral point mutations and population immunity selection, and can cause small-scale epidemics. “While the current mutations of the Omicron subviruses all belong to the latter, the changes in their immune escape and pathogenicity have remained basically at the same level without causing large changes. With the weakening of viral pathogenicity and the formation of herd mixed immunity, the new coronavirus gradually appears to shift from a world pandemic to an endemic. We found after research that changes in Omicron are also subject to natural selection, and those viruses with abnormal mutations tend to be killed by nature first.” Jin Dongyan said.

In terms of immunization, Dong-Yan Kim believes different vaccine combinations have different effects. The intramuscular vaccine is more protective of the lungs, while the inhalation and nasal spray vaccines are slightly less protective of the lungs than the intramuscular vaccine, but they are very protective of the mucous membranes of the upper respiratory tract. Natural infection activates both mucosal and humoral immunity, forming a good “protective film” for both the lungs and upper respiratory tract, so the combination of “mRNA vaccine/inactivated vaccine + nasal spray/inhalation vaccine” has the potential to achieve similar or better protection than natural infection. If the combination of mRNA vaccine/inactivated vaccine + nasal spray/inhalation vaccine is used, it is possible to achieve similar or better immunity than natural infection. “This is why we must have thorough and continuous vaccination.” Jin Dongyan stressed.

As for natural infections, Kim says it has a “triple effect”: First, the body gains antibodies, which can improve its own immunity to the new coronavirus in the short term. Secondly, even if the infection is repeated, the viral load in the body will be lower than the initial infection, and the course of the disease will be shorter, and the probability of serious illness or death will be reduced. Third, the infectiousness of the new coronavirus in the body will also be greatly reduced after the re-synthesis. Of course, Jin Dongyan also stressed that the protective effect of natural infection is not immediate, so there is a “window period”, that is, there may be a “small peak” after the end of the “peak of infection”. “However, with the dual effect of natural infection and vaccine, the possibility of a pandemic and outbreak of the new coronavirus will be greatly reduced.

In Hong Kong, for example, Jin Dongyan said, “in February this year (2022), Hong Kong outbreak trend, the entire February ~ April Hong Kong’s epidemic are more serious, but after the end of the outbreak, until now, Hong Kong is in a relatively stable stage. The reason for this is that immune protection after natural infection has worked, and the fact that most people in Hong Kong are vaccinated. We (Hong Kong) have a high vaccination rate for all two and three doses of the vaccine. As of Dec. 7, population-wide, the three-dose vaccination rate in Hong Kong is 82.6 percent and the two-dose vaccination rate is 92.9 percent.”

“The weakness of the current global epidemic is concentrated in two areas: the older elderly and younger children. These two parts of the population have weaker immunity themselves, plus many people are not vaccinated for medical reasons, so the virus is likely to ‘break through’ from these two parts of the population and cause a larger area of infection.” Jin Dongyan said.

What should be done next to defend against the virus? Jin Dongyan believes that there are four priorities: firstly, we call on people to wear masks, which is one of the lowest cost ways to prevent infection; secondly, as far as possible, vaccination, if inactivated vaccine, try to complete three to four shots of vaccination; public places to maintain ventilation, “Hong Kong mandates that restaurants and other public places must be ventilated six times every hour”; for the more vulnerable elderly and seriously ill people, the vaccine is not available. For the more vulnerable elderly as well as seriously ill patients, it is important to strengthen the monitoring of their data, such as what is the full rate of ICU, of which the rate of admission due to the new crown and what is the rate of admission, only to strengthen the key monitoring of key populations, in order to make the condition clear.