Omicron is iterating rapidly, is vaccine "anxiety" necessary?

The new Omicron subtypes BA.4 and BA.5, which are more contagious, have recently attracted attention. The new subtype has caused a new peak of infection in South Africa, and the Portuguese National Institute of Health also estimates that its growth advantage is 13% greater than BA.2.

Screenshots from the nextstrain website show that the different Omicron branches represented by yellow, orange and red have been iterating rapidly within half a year, and the new branches represented by orange and red are also constantly expanding in the cracks.

New branches of Omicron are emerging frequently. Is the current COVID-19 vaccine still effective? Do branches such as BA.2 and BA.5 need their own vaccines? Should the update of the COVID-19 vaccine keep up with the mutation of the virus? How to keep up with the mutation of the virus? With the above questions, Science and Technology Daily reporters contacted and interviewed a number of industry experts.

Are current vaccines still effective?

The Omicron variant branch continues to trigger new peaks of infection. Does this mean that the current new crown vaccine will be ineffective?

An authoritative expert in the industry responded to a reporter from Science and Technology Daily, saying: "The current vaccines can still provide the most basic protection in ensuring the reduction of severe illness and death. The COVID-19 pandemic has lasted for two and a half years. At present, it seems that it is no longer possible to achieve zero infection through vaccination for the new coronavirus. The new coronavirus vaccine can ensure the reduction of infection and the avoidance of severe illness and death."

Regarding the role of current vaccines in epidemic prevention and control, the person in charge of the COVID-19 vaccine production company held the same view: "The existing vaccines currently have no problem in preventing severe illness and death, but they will not prevent infection 100%."

Many real-world statistics or research results show that current vaccines are effective in preventing severe illness and death. For example, the latest data from Hong Kong (as of May 25) showed that the mortality rate of unvaccinated Omicron-infected people was 3.04%, while the mortality rate of infected people who received three doses of the vaccine dropped significantly to 0.04%.

Do BA.2, BA.5 and other branches need their own vaccines?

According to the latest WHO weekly report on the progress of the COVID-19 epidemiology (May 25), Omicron BA.2 and its descendant lineage (BA.2.X) have become the main variants prevalent worldwide. Currently, the relative proportions of BA.2.X, BA.4 and BA.5 are 94%, 0.8% and 1% respectively.

This shows that in the evolution of the Omicron variant, the BA.1 branch is disappearing. However, the reporter learned that most of the vaccines against Omicron in my country are currently designed and developed for BA.1.

Whether it is necessary to develop a new vaccine against the new branch, the industry generally judges from the perspective of vaccine protection: if the neutralizing antibodies produced by the original vaccine are significantly less active against the mutant strains, a new vaccine needs to be developed; if it still has a good neutralizing effect on the mutant strains, there is no need to develop a new vaccine.

Although the Omicron strain mutates quickly and has different branches, new vaccines will not be launched for each branch, nor is there a need to do so. Relevant experts remind: "If you continue to monitor, you will find that many mutations will disappear quickly."

Can vaccine updates keep up with virus iterations?

Among the technical routes for the development of the new coronavirus vaccine, the mRNA vaccine design cycle is relatively short. Based on the maturity of the platform, the design can be completed within 7 days, and preclinical trials including animal trials can be completed in about 1 month.

Industry experts engaged in the development of mRNA vaccines said that for variant branches, mRNA vaccines do not need to obtain strains, but only need to properly optimize the vaccine sequence and test the expression efficiency for the variant sequence, and then conduct preclinical trials. The mRNA vaccine for the new coronavirus variant Omicron developed by Suzhou Abogen Biotechnology in my country has obtained a clinical research approval from the UAE.

In response to virus mutations, the inactivated vaccine technology route can also complete preclinical research on new strains in a relatively short period of time by establishing an emergency response system. The reporter previously learned that it can be advanced to the clinical trial application stage about two months after obtaining a new strain.

Keeping up with mutations, can the new coronavirus vaccine be marketed based on the “influenza model”?

In order to cope with the frequently mutated viruses, there is a precedent for keeping up with the vaccine updates. For example, the influenza virus vaccine is recommended by the World Health Organization every year, and countries produce new influenza vaccines based on the recommended strains.

In order to keep up with the mutation of the new coronavirus, can the launch of the new coronavirus vaccine draw on the "influenza model"?

"The development of new coronavirus vaccines in the future will probably need to adopt the influenza model." The aforementioned authoritative expert responded, but the WHO cannot recommend mainstream strains through monitoring now because the pandemic is not over yet.

Another advantage of the "flu model" is that it greatly shortens the time it takes for new vaccines to be marketed. Since there is no need for re-approval, the batch release system it adopts can effectively shorten the cycle from vaccine development to market launch. Industry experts said that after polishing and construction, various technical route platforms have gradually matured, the speed of research and development has accelerated, and the production process has stabilized. If the new crown vaccine can adopt the "flu model" for research and development and marketing, it will greatly shorten the time it takes for new vaccines to be marketed.

The WHO disclosed some unexpected phenomena in its Weekly Epidemiological Report: Available data showed that BA.4, BA.5 and BA.2.12.1 spread faster in countries where BA.1 was prevalent, and were less common in countries where BA.2 was prevalent; the degree of vaccination in each country may have an impact on the prevalence of the new Omicron branch. It can be seen that the mutation of the new coronavirus and the immunogenicity of the vaccine are mutually causal and widely related, and timely updating of vaccines may have an impact on virus mutation.

Source: Science and Technology Daily