Experts call for: expand and strengthen the scope of application of needles to deal with mutant strains
On November 20, in an exclusive interview with a reporter from Science and Technology Daily, Zhang Yuntao, chief scientist of Sinopharm Group China Biotechnology, said that expanding the scope of application of enhanced needles can effectively deal with mutant strains.
In the previous press conference of the State Council’s Joint Prevention and Control Mechanism, Wang Huaqing, chief expert of the China Centers for Disease Control and Prevention’s immunization program, introduced that relevant units have carried out research on the new crown inactivated vaccine booster. After the research, not only the increase in antibody levels, but also the discovery of antibodies The spectrum is wider, which means that stronger protection against mutant strains will produce better protection.
American immunologist Anthony Fauci once stated in the media: The booster vaccination is probably not two shots and then boost, but more like a trilogy of complete vaccination, similar to the three shots of hepatitis B vaccine.
In this regard, Zhang Yuntao explained that many of the complete immunization procedures for other virus vaccines that are being vaccinated are 3 shots, such as hepatitis B vaccine, DPT vaccine, and IPV (poliovirus) vaccine.
However, due to the urgency of the epidemic and the tight schedule, the global new crown vaccine has not optimized the immunization program to the best in a short period of time under the premise of ensuring safety and effectiveness, but it is gradually being optimized with the accumulation of vaccine use experience.
From the WHO's "stop" to the "popularity" of various countries, strengthen the needle strength to highlight
On November 19, about two months after China's booster vaccination was steadily advanced, the U.S. Food and Drug Administration (FDA) approved the new crown vaccine booster for people 18 years and older.
Prior to this, Israel and Canada had already started intensive injections.
For the booster vaccination, once experienced opposition and doubts——
According to media reports, in July, the US company's application for an emergency use authorization for the new crown vaccine booster was opposed by the FDA and the US Centers for Disease Control and Prevention (CDC).
The WHO has also stated that since there is no conclusive evidence for the need for booster vaccination, it is recommended to suspend vaccination.
However, many countries with high vaccination rates have still found breakthrough cases (infected after vaccination). For example, the effective rate of vaccine prevention in Israel and other countries has continued to decline. The protective power is gradually becoming more prominent.
Israeli officials have issued a report saying that the risk of contracting the new crown virus can be reduced by more than 10 times after two weeks of intensified vaccination.
Intensified injection is an effective response to "mainstream strains"
One of the characteristics of Delta, the "mainstream strain" in many countries, is its short incubation period.
The incubation period is short, indicating that Delta is good at fighting "blitz". At this time, if you want to use immune memory to mobilize immune forces, it will be too late.
The former is one or two days and the latter one or two weeks, so breakthrough cases are prone to occur.
"Previous viruses have a long incubation period and do not move so fast. It takes time to incubate. Our body needs time to mobilize the immune system. The immune memory formed by the vaccine is sufficient to resist the virus." Zhang Yuntao analyzed that the effective rate of infection prevention is still high. It doesn't seem very important.
However, with the prevalence of the delta strain, the effective rate of vaccine prevention in Israel and other countries has dropped to about ten percent in the past, indicating that immunization strategies need to be adjusted.
So, how to subdue a virus with a short incubation period?
The short incubation period means that it will be amplified as soon as it becomes infected. If it can maintain a high titer of neutralizing antibodies in the human body and form a high-pressure situation, it will prevent its expansion and infection.
"There is a positive correlation between high titers of neutralizing antibodies in the body and infection." Zhang Yuntao said, therefore, after the incubation period of the new coronavirus becomes shorter, it is particularly important to strengthen the needle to stimulate more neutralizing antibodies.
There are rules to follow for the booster needle to enter the immunization program
The "0, 1, 6" program is a very classic immunization program, which means that 3 injections are required during the initial immunization of the vaccine, in the order of 0, 1, and 6 months. After the first injection, the interval is 1 and 6 months. Inject the second and third shots of vaccine.
The complete immunization program for hepatitis B vaccine, DPT vaccine, IPV vaccine and other vaccines is 3 shots.
According to reports, based on years of experience accumulated in the field of vaccine research and development, Sinopharm Sinopharm conducted a 3-dose immunization clinical trial at the earliest stage of the new crown vaccine clinical trial.
"In April last year, we launched the third needle clinical trial. At that time, due to tight time, the third and second needles were separated by one month. After the third injection, the antibody increased by 30%." Zhang Yuntao told Science and Technology Daily The reporter said that subsequent explorations showed that the effect of the third injection interval was increased after the interval was extended, and then a clinical trial of 3 programs with different doses of "0, 1, 4", "0, 1, 6" and "0, 1, 9" was carried out. .
Zhang Yuntao explained that the results of clinical trials showed that the 6-month interval between the third and second injections is more scientific, and there is no problem with the interval of 9 months.
So, can the interval be shorter?
Studies have shown that there is no problem with safety, but the neutralizing antibody titer produced is not as high as more than 6 months, and the immune effect is not so good.
During the interview, Zhang Yuntao repeatedly emphasized that the new crown virus and the new crown vaccine are very special, and they are constantly refreshing human cognition.
Many issues are still unclear until today, and they are in the exploratory stage. They need to be continuously studied and adjusted in a scientific manner to adapt to changes in the virus mutation and other circumstances.