What is the effect of the third injection of domestic inactivated vaccine?
In accordance with the unified deployment of the State Council's joint prevention and control mechanism, in order to further strengthen the immune barrier, after preliminary preparations, various localities have initiated enhanced immunization against the new coronavirus vaccine and provided "enhanced injection" services.
Recently, there have been confirmed cases and asymptomatic infections in Xinjiang, Gansu, Inner Mongolia, Shaanxi and other places.
Does the domestic inactivated vaccine have a protective effect on the new coronavirus, especially the Delta mutant strain?
What is the effect of the "strengthening needle" injection?
The reporter interviewed Xu Kaifeng, chief physician of the Department of Respiratory Medicine, Peking Union Medical College Hospital.
"Published data in Guangzhou show that people who have been injected with domestically-made inactivated vaccines have a stronger preventive effect. Compared with people who have not been vaccinated, the risk of delta new crown infection for people who have been vaccinated is only 0.25 (0.09~0.68). ), that is, the risk of infection is reduced by about 75%, and the vaccine's effective rate is about 70%." Xu Kaifeng introduced that an analysis of critically ill or critically ill people found that severe or critically ill patients occurred in people who had not been vaccinated with the new crown vaccine.
This shows that the domestic vaccine is not only effective against the new coronavirus (including the delta mutant), but also has a particularly outstanding effect on preventing severe illness.
"For readers who are still hesitant, wait and see, and have not yet been injected with the new crown vaccine, please arrange vaccination as soon as possible. There is no contraindication to injection for most patients with chronic diseases." Xu Kaifeng said.
After 6 months of vaccine injection, has the antibody titer decreased?
Xu Kaifeng said that although the inactivated vaccine can achieve a good positive rate and protective effect after injection, the study found that after 6 months, the antibody titer decreased significantly compared with that after injection (the positive rate dropped to 16 %~35%).
"The new crown vaccine is not once and for all. It does need a booster shot. The third shot is not a simple repetition, and the antibody response titer is high for a long time." Xu Kaifeng said, in order to discuss how to administer the third shot, Kexing Vaccine was divided into 4 groups for a comparative study. It was found that about 6 months after the second injection, the antibody titer decreased significantly, but after the third dose, the antibody titer could quickly rise to a high level.
In addition, 6 months after the third injection, most of them still maintained positive titer, and the positive rate of antibody was 61%~66%.
"It is foreseeable that if the third dose is injected 6 months later, higher antibody titers can be obtained, and a higher positive level is expected to be maintained in the following 6 months." Xu Kaifeng said.
At present, the research on the third dose of vaccine is mainly carried out in the same product or products of the same technical route. Whether the third dose of new crown vaccine can adopt vaccines of different technical routes remains to be further studied.
"The preventive effect of the domestic inactivated COVID-19 vaccine is very precise, and it has a protective effect of up to 70% against the delta mutant strain, and has a strong preventive effect on the risk of severe and critical illness." Xu Kaifeng finally emphasized that in addition to vaccination against the new coronavirus, In daily life, wearing masks, maintaining social distancing and paying attention to personal hygiene cannot be relaxed.
(Our reporter Cui Xingyi)