CGTN:
How long will the three vaccines currently in use be effective for? Will it be necessary to get inoculated again at a later date? Also, another issue that may concern people is: Is it necessary to continue wearing a mask after being inoculated? Thank you.
Zeng Yixin:
I'll take your questions. The first thing to note is that it has been less than a year since the virus was first detected, so it's too early to say for sure how long the vaccines will protect people after inoculation. This will require follow-up studies, from which we hope to see good results. We do however have some information that can help us make some predictions.
First, tests on animals started in February at the Institute of Laboratory Animal Sciences of the Chinese Academy of Medical Sciences which have proved that the vaccine can protect monkeys that have been inoculated. The monkeys are still in the institute, so we can continue testing them for the virus. Recent tests have shown the vaccine remains effective on the monkeys nearly nine months on.
Second, many volunteers participated in the phase 1 and phase 2 clinical trials launched in March. We have found that their antibodies are still present during follow-up tests.
Third, many medical institutions have conducted follow-up antibody tests on discharged patients. Shenzhen Infectious Diseases Hospital discharged its first COVID-19 patient on Jan. 23, and has followed-up on over 400 patients in total. They found that the antibodies are still present with some people even having them for as long as 10 months. All this evidence points with few doubts to the vaccine being effective for over six months as the World Health Organization has required. Of course, it is yet to be determined if it can provide lifetime protection to those who have been inoculated, or at least five to 10 years.
There was also a question just now as to whether it will be necessary to be inoculated annually, like with the flu jab. The question here is: why is the flu shot given once a year? It is not because it works for less than a year, but because the influenza virus mutates very quickly. It may be one variant spreading this year and another spreading next year, so we have to adjust the vaccines. The issue is not the duration of protection, but rather the mutation of the virus causing different variants to spread. Therefore, an optimistic estimate would be that it is unlikely for people to need to be inoculated once every year or half a year.
The previous speakers briefed you on the relevant anti-epidemic measures just now. We believe that the vaccines are safe and effective, but that once inoculated, people still need to ensure their effective personal protection, including mask wearing, social distancing and frequent hand washing. After all, the vaccines cannot provide 100% protection, just like all other vaccines. In particular, we have not achieved herd immunity, so we suggest that people continue to take safety precautions even after being inoculated. Thank you.
