Why is the COVID-19 vaccine given twice? About the age range of the key population receiving the third dose of COVID-19 in China

No one wants to be infected with COVID-19. Although the situation in China is much better now, daily protection still needs to be done well. In addition to sticking to wearing masks, people should also be vaccinated as soon as possible. This is the basis for establishing a crowd protection barrier and also for blocking the spread of the virus. Can COVID-19 emergency vaccines be given to older people?

In the process of COVID-19 vaccination nationwide, vaccination is carried out in all places according to the principles of separating regions, giving priority to ports, prioritizing priorities, and being safe and orderly. At present, the focus of vaccination in China is on high-risk and potentially high-risk populations aged 18 to 59. Currently, the vaccination population in China is divided into three groups: the elderly group, the adult group, and the younger group. This is not a strict classification, different clinical designs will have different groupings. For example, special groups such as pregnant women and those with various underlying diseases will also be grouped separately. After the age group of 18 to 59, the next group to consider for vaccination is the older age group of 60 and above. The age range of this group is very large, for example, people aged 60 to 80 have relatively strong activity ability, while people over 80 have significantly weakened activity ability. The specific next steps are currently being studied and evaluated.

According to the results of previous research, to block the transmission of COVID-19, the threshold of population immunity level is about 70%, and the threshold is proportional to the protective effect of the vaccine and the vaccination rate of the vaccine. After the first step of implementing immunization for key populations, it will be expanded to other populations in the future. When the vaccination rate in the population reaches a very high level, this immune barrier is established. Therefore, we hope that when you have the opportunity to vaccinate, you should plant as many as you can, and we hope that the epidemic of COVID-19 will be terminated through immunization prevention measures, or that it will be controlled at a very low intensity, with only some sporadic cases.

Why is COVID-19 vaccine given twice?

A certain amount of antibody will also be produced in the body after one injection of COVID-19 vaccine, but generally, one injection of vaccine is not enough, and it is necessary to wait for another injection of vaccine after 14-28 days to strengthen immunity. Even after two injections of COVID-19 vaccine, it is uncertain whether it can produce permanent protection. The current research shows that the protection of COVID-19 vaccine can last for at least half a year. It is uncertain whether it will gradually weaken after half a year. It is also uncertain whether it needs to inject vaccine again to strengthen immunity, which needs further research.

In view of the problem that some people report that the second dose of COVID-19 vaccine is difficult to vaccinate, the Disease Control Bureau of the National Health Commission will strengthen the connection between supply and demand, and give priority to ensuring the vaccination demand of the second dose of vaccine when formulating the vaccine distribution plan. According to the requirements of the Technical Guidelines for Vaccination of COVID-19 (First Edition), the second dose of inactivated vaccine can be completed within 3 to 8 weeks after the first dose, and in special cases, vaccines from different manufacturers with the same technical route can be replaced.