Chinanews.com, Beijing, December 28 (Wei Xianghui) Not long ago, "Nature" magazine (Nature) announced the "Top Ten People" (Nature's 10) of scientific influence in 2022 (Nature's 10). Cao Yunlong, the leading scientist of Beijing Changping Laboratory, was selected.

　　This list aims to select ten people who have made important contributions to major scientific progress in the past year.

Cao Yunlong was selected because, as a COVID-predictor, he tracked the evolution of the new coronavirus and accurately predicted the emergence of new mutations and new strains.

　　A few days ago, Chinanews.com interviewed Cao Yunlong and discussed topics such as the characteristics of several major virus strains that are currently prevalent in the world, the pathogenicity changes of Omicron, and infection prevention and control strategies.

Different mutant strains can cause multiple infection peaks per year

　　According to Cao Yunlong, BA.5.2 and BF.7 are mainly popular in China at this stage, both of which belong to the BA.5 branch of Omicron.

He said that most of the people in our country were vaccinated with the original strain of the vaccine, and the humoral immunity induced by it was severely escaped by the Omicron mutant strain. In addition, most people had been vaccinated for more than a year, and the level of neutralizing antibodies in the body declined, which further weakened the prevention The role of infection.

　　He mentioned that after being infected with BF.7, the level of neutralizing antibodies to BA.5 and BF.7 is high, and the same strain will not be re-infected within a short period of time.

However, compared with BA.5.2 and BF.7, new strains such as BQ.1.1 and XBB, which are currently prevalent in the world, have stronger immune escape ability. Even if infected with BF.7, the antibodies produced after recovery are against XBB The neutralizing ability of the latest mutant strains is also lower.

Therefore, it is foreseeable that after the domestic BA.5.2 and BF.7 infection peaks have passed, it is not ruled out that there will be infection peaks driven by BQ.1.1, XBB or other strains with stronger immune escape capabilities.

Photo courtesy of respondents to a large cohort study on the rate of reinfection of the new crown in the Israeli population

　　In other parts of the world, superinfection has become commonplace.

According to the data provided by Cao Yunlong, the reinfection rate of the latest epidemic strains such as BQ.1.1 and XBB has reached 40%, and continues to rise.

He said that this year, most countries have experienced four waves of major infection peaks, most of which were induced by different mutant strains, with an average of once every three months.

At present, it seems that it is difficult to completely avoid it in China.

Focus on pathogenicity of Omicron in high-risk populations

　　Cao Yunlong said that the overall decline in the pathogenicity of Omicron seen now is mainly due to the popularization of vaccination and the enhanced immunity caused by infection of a large number of people.

Although the immune barrier established by vaccines and natural infection cannot effectively prevent infection, it can reduce symptoms, so it seems that the pathogenicity of the virus has decreased.

But he stressed that this is not comparable to the natural toxicity of the virus.

　　Cao Yunlong mentioned that there are still many people in the social group who cannot be vaccinated or cannot produce an effective immune response after vaccination, such as immunocompromised people, elderly people, and tumor patients. They are also high-risk groups for severe illness and death after COVID-19 infection , so the pathogenicity of Omicron in these high-risk populations still needs to be monitored.

　　He introduced that in the United States, the United Kingdom, Japan and other countries, Omicron has caused a huge burden of death and severe disease.

For example, in the United Kingdom, the total number of deaths caused by Omicron BA.1 is comparable to that of Delta. Although the peak death rate showed a downward trend from BA.1→BA.2→BA.5, the cumulative total number of deaths did not increase significantly. decline.

However, the number of severe cases and deaths caused by the epidemic in Japan this winter has approached historical records and has not yet shown a downward trend.

　　Cao Yunlong said that the current vaccines have a good preventive effect on severe diseases, and it is still of great significance to increase the vaccination rate of the elderly.

For those who are not suitable for vaccination, other coping strategies need to be explored.

Japan's daily new crown deaths in the past two years

Broad-spectrum neutralizing antibodies are expected to improve treatment and prevention efficiency

　　Cao Yunlong believes that how to make the development cycle of vaccines and antibody drugs keep up with the speed of virus evolution is a follow-up problem that needs to be solved.

　　"The clinical development of an antibody drug often takes half a year to a year, that is, the premise that it can benefit society is that the antibody can cope with the epidemic virus in the next six months to a year." Cao Yunlong said that the new coronavirus mutates quickly , and have strong immune escape characteristics, how to select and develop broad-spectrum antibody drugs is very important to make drug development keep up with virus mutations, and it is also a pain point in the current development of vaccines that can effectively prevent infection.

　　Cao Yunlong's team established a prediction model for the new crown immune escape mutation site.

He said that by predicting the mutations that will occur in the new crown in the future, antibody drugs that are not affected by these mutations can be selected in advance for clinical development.

　　Currently, Cao Yunlong's team has developed two broad-spectrum neutralizing antibodies SA55 and SA58.

According to reports, these two antibodies were screened from SARS patients who had been vaccinated with the new crown vaccine, and their sites of action avoided the dominant immune epitopes of population immunity, making it difficult for them to escape.

　　"SA55 has almost no similar antibodies in the current population immune background, and it is currently the only antibody that is in the clinical development stage and is effective against all known novel coronavirus strains." Cao Yunlong introduced that SA55 and SA58 are currently undergoing clinical trials For the test, the product dosage forms include injections and sprays.

Among them, injections can be used for treatment and long-term prevention of moderate to severe diseases, especially for those who are not suitable for vaccination or have poor immune responses, such as the elderly or immunocompromised people.

　　Compared with injections, sprays act directly on the upper respiratory tract, requiring only a very low dose to prevent infection.

Preliminary placebo randomized controlled trial data show that the protective efficiency of SA58 spray for post-exposure prophylaxis against symptomatic infection can be as high as 80%.

"SA55 is more active, the prevention efficiency is expected to be higher, and the required dose will be lower and the cost will be lower."

　　Cao Yunlong mentioned that SA55/SA58 spray is expected to become a new crown prevention and treatment product that can be used daily by the whole people at home, and is currently preparing for a more rigorous double-blind clinical trial.

Schematic diagram of the use of neutralizing antibodies for the new crown nasal spray Photo courtesy of the interviewees

　　"Although there is no guarantee that SA55 will not escape in the future, my team and I are already developing other candidate antibodies. If SA55 is escaped by a new strain, new antibodies can be replaced immediately." Cao Yunlong said that in addition to broad-spectrum antibodies, he and The team will also develop a broad-spectrum new crown vaccine to solve the technical bottlenecks faced by existing vaccines.

(use up)