The "protection period" of new crown antibodies is coming, do you need to be vaccinated again?

◎ Zhang Jiaxing, reporter of this newspaper

"With time, the titer of the new crown neutralizing antibody in the body will indeed slowly decrease." On April 4, Dai Lianpan, a researcher at the Institute of Microbiology of the Chinese Academy of Sciences, said in an exclusive interview with Science and Technology Daily that if you want to effectively prevent reinfection, it is necessary to re-vaccinate against the new crown vaccine before the antibody in the body drops significantly.

The peak of new crown infection at the end of last year, more than 4 months have passed, do I need to be vaccinated against the new crown in the future? How to effectively reduce reinfection? Experts popularized this science.

Feel that the new crown is no longer coming, do you still need to be vaccinated?

Will the covid still come? Many people recently feel that the new crown virus seems to have disappeared and has not brought about a larger infection.

Dai Lianpan said that the epidemiological trend of virus transmission is currently difficult to predict. For example, influenza viruses, which year there will be an outbreak is difficult to predict in advance, but many people will be vaccinated against influenza every year in case of possible pandemics and major outbreaks.

"The new crown virus may also be epidemic in a certain period of time and within a certain geographical range in the future, and this law has not been clearly studied so far." Dai Lianpan explained that vaccination is the most effective and economical means to prevent infectious diseases. Reduce the harm caused by infection by preventing it before it occurs. Future vaccination strategies, such as how often to get vaccinated, still need to be further studied and decided by relevant authorities.

This group of people needs to be strengthened even more

"Antibody levels are positively correlated with protective effect, which means that the lower the level of neutralizing antibody, the worse the protective effect, and vice versa." Dai Lianpan said vaccination can raise the level of neutralizing antibodies in the blood, which can be stopped when the virus enters the bloodstream.

So, after the last infection, is it already equivalent to vaccination?

"For people who have already received 3 injections and re-infection, it is equivalent to superimposing immunity and obtaining strong immunity, which is confirmed by many studies." Dai Lianpan said that for people who were not vaccinated before infection or were infected without completing the full course of vaccination, the immune protection in the body is not as good as the former.

All the same infected people, why is the immune protection different?

Dai Lianpan explained that the coverage of neutralizing antibodies in the body is mainly different, and the people who are infected with 3 time after 1 vaccinations are stimulated by the superposition of the prototype strain and the Omicron subvariant, while the 1-infected people are only stimulated by the single stimulus of the Omicron subvariant, and the former has a wider coverage than the latter. Especially when a new variant is coming, the superimposed stimulus may also cover the unknown mutation of the new variant, producing a better immune effect.

"Therefore, in order to cope with possible mutations of Omicron in the future, people who were not vaccinated before infection or were infected before the full vaccination need to be vaccinated again." Dai Lianpan said.

Further reinforcement is effective in preventing the spread of variants

Immunity is not only an individual's infection problem, but also can affect the spread and mutation of the virus by forming herd immunity.

"Strengthening at a time when antibody levels have not completely fallen at this stage is not only beneficial to individuals, but also beneficial to the formation of herd immunity." Dai Lianpan said that if everyone strengthens now, then even if a new coronavirus variant is imported, it will be difficult to spread quickly due to the role of the immune barrier and cannot form a peak of infection.

In addition, herd immunity is done well, and the vulnerable groups in the whole population are also invisibly protected. Dai Lianpan explained that the immune barrier is susceptible groups, such as some people who have not been vaccinated for various reasons, high-risk groups, elderly groups, special groups, etc., which effectively resist the harm caused by viral infection.