The new branches BA.4 and BA.5 of Omicron, which are more powerful, have recently attracted attention.
The new branch has triggered a new peak of infections in South Africa, and the Portuguese National Institute of Health also estimates that its growth advantage is 13% higher than that of BA.2.
The screenshot from the nextstrain website shows that the different Omicron branches represented by yellow, orange and red have been iterated rapidly within half a year, and the new branches represented by orange and red are also expanding in the cracks.
New branches of Omicron are frequently emerging. Is the current new crown vaccine still effective?
Do branches such as BA.2 and BA.5 need their own vaccines?
Should the update of the new crown vaccine keep up with the mutation of the virus?
How to keep up with the virus mutation?
With the above questions, reporters from Science and Technology Daily contacted and interviewed a number of industry experts.
Are current vaccines still effective?
The mutated branches of Omicron continue to cause new infection peaks. Does it mean that the current new crown vaccine will fail?
In response to a reporter from Science and Technology Daily, an authoritative expert in the industry said: "The current vaccine can still provide the most basic protection in ensuring the reduction of severe illness and death. The new crown epidemic has lasted for two and a half years. At present, it seems that for the new crown virus, it is necessary to pass vaccination. The possibility of a vaccine achieving zero infection is gone. The new crown vaccine can ensure the reduction of infection and the effect of avoiding severe disease and death.”
Regarding the role of the current vaccine in epidemic prevention and control, the person in charge of the new crown vaccine-related production enterprise holds the same view: "The existing vaccine currently has no problem in preventing severe illness and death, but it will not prevent 100% infection."
A number of statistics or research results from the real world show that the current vaccine has a significant effect on preventing severe illness and death.
For example, the latest data from Hong Kong (as of May 25) showed a 3.04% mortality rate among unvaccinated Omicron infected persons, and a significant drop in mortality of 0.04% among infected persons who received the 3-dose vaccine.
Do branches such as BA.2 and BA.5 need their own vaccines?
According to the latest epidemiological progress report of WHO's new crown (May 25), Omicron BA.2 and its descendant lineage (BA.2.X) have become the main variants of global epidemics. At present, BA. The relative proportions of 2.X, BA.4 and BA.5 are 94%, 0.8% and 1%, respectively.
This suggests that the BA.1 branch is disappearing during the evolution of the Omicron variant.
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 for a new branch, the industry generally judges from the perspective of vaccine protection: if the neutralizing antibody produced by the original vaccine has a significant decrease in activity against the mutant strain, a new vaccine needs to be developed; neutralization, there is no need to develop new vaccines.
Although the Omicron strain mutates rapidly and has different branches, there is no new vaccine for each branch, and there is no 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?
In the technical route of the new crown vaccine development, the mRNA vaccine design cycle is short. On the basis of the mature platform, the design can be completed within 7 days, and the preclinical test including animal testing can be completed in about 1 month.
Industry experts engaged in the research and development of mRNA vaccines said that for mutant branches, mRNA vaccines do not need to obtain strains, but only need to properly optimize the vaccine sequence for the mutant sequence and test the expression efficiency, and then preclinical tests can be carried out.
The mRNA vaccine of the new coronavirus Omicron variant developed by Suzhou Aibo Biotechnology in my country has obtained the approval for clinical research in the United Arab Emirates.
In response to virus mutation, the inactivated vaccine technical route can also complete preclinical research on new strains in a relatively short period of time by establishing an emergency system.
The reporter previously learned that it can be advanced to the clinical trial application stage about 2 months after obtaining the new strain.
Keeping up with the mutation, can the new crown vaccine market learn from the "flu model"
There is precedent for vaccine updates to follow closely in response to frequently mutating viruses.
For example, influenza virus vaccines are recommended strains issued by WHO every year, and countries produce new influenza vaccines accordingly.
In order to keep up with the mutation of the new crown virus, can the new crown vaccine market learn from the "flu model"?
"The development of a new crown vaccine in the future is estimated to need to use the influenza model." The aforementioned authoritative experts 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 the dramatic reduction in the time to market for new vaccines.
Since there is no need for re-approval, the batch release system it adopts can effectively shorten the cycle from vaccine development to marketing.
Industry experts said that after polishing and construction, each technology route platform has gradually matured, the research and development speed has been accelerated, and the production process has been stabilized. If the new crown vaccine can be developed and launched in the "influenza model", the time to market of new vaccines will be greatly shortened.
WHO revealed something unexpected in its weekly epidemiology report: Available data show that BA.4, BA.5 and BA.2.12.1 spread faster in countries where BA.1 was endemic, and in BA.2 Endemic countries are rare; the level of vaccination in each country may have an effect on the prevalence of the new branch of Omicron.
It can be seen that the mutation of the new coronavirus and the immunogenicity of the vaccine are causal and widely related, and the timely update of the vaccine may have an impact on the mutation of the virus.
Reporter Zhang Jiaxing