How long does the vaccine's protection rate last?
The existing data shows that, like the normal vaccine, the antibody level in the vaccinators will decrease after the vaccination. Six months after the whole immunization course, the neutralizing antibody level in the target dose groups of various vaccines will decrease by about 1.4 to 12.4 times.
However, the decline of antibody level does not mean that the protection of the vaccine disappears. But data about at what level the protective effect will disappear is still being collected for research at present.
The research results of booster immunization carried out by some units show that the neutralizing antibody can be significantly improved in a very short period if booster injection is given in 6 to 12 months after the whole course of immunization. This shows that the first stage of vaccine immunization has generated a very good immune memory, which can be maintained at least one year.
Is COVID-19 booster vaccination necessary?
There is not enough evidence that a third dose of vaccination is needed for the whole population.
Preliminary observation showed that it is not necessary to carry out booster vaccination for people who have completed the immunization course within one year. However, for the elderly and patients with underlying diseases who have completed immunization for more than 6-12 months with relatively weak immune function, as well as the personnel who have to work in high-risk areas, and those who engaged in high exposure risk occupations in China, whether it is necessary and when to carry out booster vaccination for them are still being studied.