The “protection period” of the new coronavirus antibodies is almost over. Do I need to get vaccinated again?

"As time goes by, the titer of new coronavirus neutralizing antibodies in the body will indeed slowly decrease." On April 17, Dai Lianpan, a researcher at the Institute of Microbiology, 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 get vaccinated with the new coronavirus vaccine again before the antibodies in the body significantly decrease.

It has been more than four months since the peak of COVID-19 infection at the end of last year. Will COVID-19 vaccines still be needed in the future? How to effectively reduce reinfection? Experts provide scientific knowledge on this.

It feels like the new coronavirus will not come again, do we still need to get vaccinated?

Will the new coronavirus come again? Many people feel that the new coronavirus has disappeared recently and has not caused a larger-scale infection.

Dai Lianpan said that the epidemiological trend of virus transmission is currently difficult to predict. For example, it is difficult to predict in advance which year an influenza virus outbreak will occur, but many people get a flu vaccine every year to prevent possible pandemics and outbreaks.

"The new coronavirus may also become prevalent in a certain period of time and within a certain geographical area in the future, but this pattern has not been clearly studied so far." Dai Lianpan explained that vaccination is the most effective and economical means of preventing infectious diseases. By taking precautions before they happen, the harm caused by infection can be reduced. Future strategies for the new coronavirus vaccination, such as the interval between vaccinations, still need further research and decisions by relevant authorities.

This group of people needs to be strengthened

"The antibody level is positively correlated with the protective effect, which means that the lower the neutralizing antibody level, the worse the protective effect will be, and vice versa." Dai Lianpan said that vaccination can increase the level of neutralizing antibodies in the blood and block the virus when it enters the blood.

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

"For people who have received three shots and then are infected again, it is equivalent to superimposing the immunity and gaining strong immunity. Many studies have confirmed this." Dai Lianpan said, but for people who have not been vaccinated before infection or have not completed the full vaccination course before being infected, the body's immune protection ability is not as good as the former.

They are all infected people, so why do they have different immune protections?

Dai Lianpan explained that the main reason is that the coverage of neutralizing antibodies in the body is different. People who have been vaccinated three times and infected once are stimulated by the prototype strain and the Omicron subvariant, while people who have been infected once are only stimulated by the Omicron subvariant. The former has a wider coverage than the latter. Especially when a new variant strikes, the superimposed stimulation may cover the unknown mutations of the new variant and produce a better immune effect.

"Therefore, in order to cope with possible mutations of Omicron in the future, people who have not been vaccinated before infection or have not completed the full vaccination process need to be vaccinated with the new coronavirus vaccine again," said Dai Lianpan.

Further strengthening can effectively prevent the spread of variants

Immunity is not only a matter of individual infection, but can also affect the spread and mutation of the virus by forming herd immunity.

"At the current stage, when the antibody level has not completely dropped, re-strengthening will not only benefit individuals, but also help form herd immunity." Dai Lianpan said that if everyone is re-strengthening now, then even if a new variant of the new coronavirus is introduced, it will be difficult to spread quickly due to the effect of the immune barrier, and no infection peak will be formed.

In addition, herd immunity can also provide protection for vulnerable groups in the entire population. Dai Lianpan explained that the immune barrier is for susceptible groups, such as those who have not been vaccinated for various reasons, high-risk groups, the elderly, special groups, etc., which effectively resists the harm caused by viral infection.