The second generation of COVID-19 vaccine is here! Do you still need it after taking the first generation?

On December 27, the UAE Ministry of Health and Prevention approved the emergency use license for Sinopharm's second-generation recombinant protein COVID-19 vaccine. This is also the world's first second-generation COVID-19 vaccine approved for emergency use.

Image source: China Biologics WeChat official account

Many people are confused: What is the second-generation vaccine? Compared with the first-generation vaccine, where is the extra "one"? Do we still need the second-generation vaccine after taking the first-generation vaccine? To this end, Science and Technology Daily reporters interviewed relevant research and development units.

What’s the difference between the second-generation vaccines?

The second-generation vaccine approved for emergency use this time is a protein recombinant vaccine based on its technical route. my country had approved the emergency use of this type of vaccine in March this year.

"Recombinant protein vaccines are a very mature technology, not a new one." Zhang Yuntao, chief scientist of Sinopharm Group China Biologic, told Science and Technology Daily that the hepatitis B vaccine that children are given when they are born is based on this technology. Antigen proteins are synthesized in vitro and delivered into the body to produce immunity, and its safety has been verified for decades.

Since it is not a new technology, why is it the “second generation”?

The first generation of antigen protein design uses part of the virus prototype protein, such as the key region of the S protein of the new coronavirus. The second generation of vaccine development is different in the design of antigens.

Li Qiming, the head of the R&D team and the dean of Sinopharm Biotechnology Research Institute, further explained that in response to the new trend of the prevalence of mutant strains, based on the first-generation vaccine, the R&D team used the computational structural vaccinology technology platform to conduct a comprehensive quantitative computational evaluation of the immune escape ability of various mutant mutation sites through molecular simulation and computational modeling methods. The team designed and developed the second-generation recombinant new crown vaccine.

It is understood that the second-generation immune antigens are not limited to the key areas of the S protein of the new coronavirus that the industry has focused on before. In other words, the first-generation "copycat" is as similar as possible, while the second-generation modeling analysis and computational evaluation have the meaning of "guessing the charm", so it is more "intelligent" in stimulating antibodies.

What are the advantages of the second-generation vaccine?

Precisely because the immune escape ability of various variant mutation sites has been comprehensively and quantitatively calculated and evaluated from the source of antigen design, the second-generation vaccine is effective against multiple virus variants.

The clinical vaccination results in the UAE showed that the neutralizing antibody level stimulated by the second-generation vaccine was significantly better than that of the control vaccine group for the Omicron strain.

"The second-generation vaccine is developed against mutant strains and adopts a broad-spectrum design." Li Qiming said that based on current data, the sequential vaccination of recombinant vaccines and inactivated vaccines can stimulate the human body to produce higher levels of neutralizing antibodies against prototype strains and major mutant strains.

The mutation of the new coronavirus is often unexpected. Is the second-generation vaccine effective against mutations that have not yet appeared? Li Qiming said that the R&D team is cooperating with the research team of the China National Institute for Food and Drug Control to use a pseudovirus system to conduct broad-spectrum research on the vaccine. The relevant results will be published in the form of a scientific paper. Based on the current situation, it is speculated that it has a certain potential for protection against possible mutant strains.

After receiving the first-generation vaccine, do I still need the second-generation vaccine?

Data released at a press conference of the State Council’s Joint Prevention and Control Mechanism on December 29 showed that 1.27413 million people in my country have completed the full vaccination process, accounting for 85.64% of the country’s total population.

Many people have completed the vaccination of the first generation of vaccines, so do they still need the second generation of vaccines?

It is understood that in the UAE, which has approved its emergency use, the second-generation vaccine is administered as a booster shot for people who have received two doses of Sinopharm Group China Biological's inactivated COVID-19 vaccine.

Li Qiming said that based on the current data, the "inactivated + recombinant" vaccination method will greatly improve the level and durability of the vaccine recipients' immune response.

Recent related studies have also shown that the neutralizing antibody titer of subjects vaccinated with heterologous second-generation vaccines was higher than that of the homologous vaccine group; as the "third shot", Sinopharm Group China Biological recombinant protein vaccine is effective against multiple strains (including the Omicron variant), and the neutralizing antibody level is significantly better than that of the control vaccine group.

In the face of the ever-changing novel coronavirus, higher levels of neutralizing antibodies will be more conducive to the formation of a herd immunity barrier. Relevant experts said that the new clinical data and usage data will provide strong data support for the development of global novel coronavirus vaccines and the selection of vaccination strategies.