Xinhua News Agency, Beijing, March 18 (Reporters Linlin Wang and Yunjia Peng) Currently, the overseas epidemic is still severe, and the domestic epidemic has been effectively controlled.

In the choice of vaccinations against the new crown virus, many people have encountered "choice troubles": should they be vaccinated?

Which type of vaccine is better?

How to choose single needle and double needle?

In response, Xinhua News Agency reporters interviewed relevant authorities and authoritative experts in the industry.

  At present, my country has 4 new coronavirus vaccines that have been conditionally approved by the State Food and Drug Administration for marketing.

According to the technical route, there are two major categories: one is inactivated vaccines, including three inactivated vaccines produced by Sinopharm Zhongsheng Beijing Company, Sinopharm Zhongsheng Wuhan Company, and Beijing Kexing Zhongwei Company; the other is adenovirus vector vaccines. It is a type 5 adenovirus vector vaccine produced by Tianjin Kangxinuo Company.

  Which is better?

  The relevant competent department of the National Health Commission stated that no matter what technical route is adopted, as long as the country has officially conditionally approved a vaccine for marketing, its safety and effectiveness are supported by certain data, and the potential or known benefits are greater than Potential risks or known risks, the public can rest assured to choose.

  According to industry experts, the two technical routes of the new coronavirus vaccine have their own characteristics.

  Shao Yiming, a researcher at the Chinese Center for Disease Control and a consultant to the World Health Organization's Vaccine Research and Development Committee, said that inactivated vaccines are to inactivate the new coronavirus after culture and amplification, and then inject the inactivated virus particles into the human body to induce an immune response in the human body.

Because the protein antigens on the surface of part of the virus will be destroyed during inactivation, the immunogenicity of the vaccine is lower than that of the live virus, and the method of double or triple injection is often used.

The first needle induces memory cells, and the re-injection stimulates the memory response to exponentially enhance the overall immune response.

  According to Wang Junzhi, deputy leader of the vaccine research team of the scientific research group and academician of the Chinese Academy of Engineering, the main feature of inactivated vaccines is that the vaccine components are relatively close to the natural virus structure, and the immune response is usually relatively strong and has good safety.

This vaccine is relatively stable and can be stored for two to three years under storage and transportation conditions of 2 to 8 degrees Celsius.

  The adenovirus vector vaccine is like a car carrying "new coronavirus antigen genes" cargo.

After being delivered to human cells, the "new coronavirus antigen gene" neither self-replicates nor has the ability to cause disease, but it can express the protein antigen of the new coronavirus and stimulate the body's immune system to produce antibodies.

  Wang Junzhi introduced that my country’s self-developed adenovirus vector vaccine adopts "type 5 adenovirus" as a carrier and introduces "new coronavirus antigen genes", which can not only induce the production of good neutralizing antibodies, but also induce and enhance cellular immunity.

The currently approved immunization program is single-dose vaccination.

  So, how to choose between single needle and double needle?

  Shao Yiming said that for people who need to go to the epidemic area for temporary or urgent tasks, but do not have enough time to wait, it is more suitable to inject a single-dose adenovirus vector vaccine.

  In addition, the single-dose adenovirus vector vaccine has the following advantages: First, the single-dose vaccination completes the whole course of immunization, avoiding the loss of immunity caused by long distances, busy work, or lack of vaccines to receive the second injection, and guarantees high levels of immunity. The vaccination rate; second, the overall cost of a single injection is lower and the cost-effectiveness ratio is higher.

Third, in the current situation of insufficient global vaccine production capacity, a single injection of vaccine can vaccinate double the population, which improves the availability of vaccines.

  However, there are advantages and disadvantages.

Shao Yiming suggested that the immune response induced by a single-dose adenovirus vector vaccine is generally weaker than that of a two-dose vaccine.

Because when this type of vaccine is vaccinated again, the human body mainly produces a memory response to the "car"-the adenovirus vector, rather than the "cargo"-the "new coronavirus antigen gene".

This type of single-dose vaccine is no problem in preventing early epidemic viruses. When replaced with late-stage mutant viruses, the protection efficiency will mostly decrease.

Therefore, when choosing a vaccine, comprehensive judgment and scientific decision-making should be made according to the specific conditions of the population to be protected, combined with the latest monitoring data of the local epidemic virus.