China'S New Crown Vaccine Vaccination Breakthrough 500 Million Doses, Market Controversy, New Outlet For Neutralization Antibody Detection

The vaccination of new coronal vaccine in China continued to accelerate.

According to the latest data released by the National Health Commission on the afternoon of May 24, a total of 510.858 million doses of new coronavirus vaccine have been reported nationwide as of May 23. After a new round of local outbreaks in Anhui and Liaoning, China's vaccination has accelerated significantly. In the eight days before May 19, China achieved 100 million doses of new coronal vaccine. After that, the average daily inoculation rate of more than 10 million doses was promoted to a cumulative breakthrough of 500 million doses.

As the effectiveness of the vaccine can not reach 100%, with the continuous expansion of the population vaccinated with the new crown vaccine in China, antibody detection may become a new demand point in the market in the future. In view of the new coronal pneumonia vaccine, the effectiveness of the vaccine can be judged by detecting whether there is neutralizing antibody in the body.

The so-called neutralizing antibody is a kind of specific antibody that can block the virus invading cells, which is produced by the immune response after vaccination. Neutralizing antibody can neutralize the infective activity of the virus and protect the host from infection. Its titer will directly determine the clinical efficacy of the vaccine.

Normally, the CDC or R & D enterprises will track the effectiveness of any vaccine in the human body after it is launched. It is reported that at present, no neutralizing antibody test kit has been approved by the State Food and drug administration, and the follow-up study on vaccine effectiveness is mainly carried out by the National Center for Disease Control and prevention.

A person from a testing enterprise in South China told the 21st century economic report: "all testing institutions have long had a layout of neutralizing antibody detection capabilities. It is not ruled out that in the future, with the smooth progress of vaccination work, if the country needs to carry out the neutralization antibody detection work uniformly, the technical support and market layout of enterprises can be put into use immediately. The industry forecast that the nucleic acid detection will be similar to the situation of unified procurement of large quantity and gradual adjustment of price from high to low. "

"Mass immunization" still has a long way to go

Vaccine refers to the biological products made by various pathogenic microorganisms for vaccination. Vaccination is a process in which people actively accept specific immunity. Lymphocytes can specifically recognize antigenic "foreign bodies", and then their own life, proliferation and differentiation, and obtain the ability to remove "foreign bodies" and damaged cells. This is an acquired immunity, divided into cellular immunity and humoral immunity, which are mediated by T lymphocytes and antibodies respectively.

The immune response after vaccination is that some of the body can secrete specific antibodies and have immune memory. In other words, the human body can "remember" the diseases it has suffered. When the cells in vivo contact with the same antigen again, it can cause a rapid and strong immune response, so as to play a protective role.

Professor Chen Jingxian of the national respiratory disease clinical research center virus diagnosis research sub center said that at present, no matter what kind of vaccine has a good protection effect. Different products in different regions for clinical trials, using different inclusion, classification and evaluation criteria, so there is no need to tangle with a little difference in data. More accurate data will emerge over time“ I recommend using locally available vaccines. "

At present, whether the neutralization antibody detection kit developed at home and abroad can really play a role in detection effectiveness needs to be discussed. The National Center for medical device technology evaluation has mentioned in the paper "several considerations on the detection reagent of new type coronavirus neutralizing antibody". At present, the detection of neutralizing antibody mainly focuses on receptor binding domain (RBD) and N-terminal domain (NTD) of S1 Protein. Several neutralizing antibodies against S1 Protein have been reported, but they can not bind to RBD recombinant protein, nor can they recognize NTD domain.

In other words, the current kits only detect IgM or IgG antibodies against a specific antigen or protein (such as N protein, M protein, S protein or E protein) of NCV, but not the total antibody against NCV.

Chen Jingxian further explained: "the neutralizing antibody produced by the vaccine is mainly IgG, which can prevent the virus from spreading to the whole body through the blood, but it is difficult to protect the respiratory tract / digestive tract mucosa from infection. The mucosal surface is mainly protected by innate immune barrier, specific IgA antibody and cellular immunity. We expect more effective vaccines, such as live attenuated vaccines and vaccines that induce mucosal immunity in the respiratory tract. "

There are still many questions to be answered in the study of new coronavirus. Where is the source of the virus, what is the impact of mutated strains on detection and vaccine, and how long will effective antiviral drugs and more effective vaccines appear? But none of these can hinder the recovery of global economic and social life.

At present, the infection rate and mortality rate of countries with high proportion of vaccination have decreased significantly. With the gradual control of the epidemic situation in the global scope, China's door will be opened, so it is imperative to vaccinate all the people to realize mass immunization. Earlier, Zhang Wenhong, director of the infection department of Huashan Hospital Affiliated to Fudan University, once again made a speech at the launching meeting of the research on the ultra short range program of MDR-TB in China, stressing that "those who have not been vaccinated will suffer losses."

He believes that the new coronavirus will become a resident virus in the future. For each individual, the reason for vaccination is very simple, in case of infection in the future. China's inactivated vaccines have a protection rate of more than 90% to avoid conversion to severe diseases and nearly 100% to avoid death.

At present, the global epidemic is still in the epidemic, and there is still a long way to go for the population immunity level with higher vaccination rate. Global immunization needs at least two to three years, or even longer.

"Before the realization of real group immunity, even if vaccinated, we should continue to wear masks, wash hands frequently, and keep social distance, and the prevention and control of normal epidemic situation can not be relaxed." Chen Jingxian suggested.

Neutralization antibody detection needs to wait for large volume

Neutralizing antibody refers to that the body will produce anti-virus antibody after a few days or a week after the patient is infected with the disease. The neutralizing antibody, as an anti-virus antibody, only accounts for a small part of the anti-virus antibody. The neutralizing antibody can recognize the surface protein of the virus, block the binding of the virus and the specific receptor on the cell surface, thus preventing the virus from invading human cells.

The neutralizing antibodies may be IgG, IgM and IgA, but not all IgG and IgM are neutralizing antibodies. Some kits use new coronavirus nucleocapsid protein (N protein) to detect IgG or IgM. Although the antibody detected can bind to NCV N protein, it can not prevent the virus from binding with ACE2, which is not neutralizing antibody, that is to say, it has no protective effect.

It is not enough to detect the IgG and IgM of the new coronavirus, but the antibody which can recognize the neutralizing epitope of s-rbd is the key. Therefore, it is necessary to evaluate the efficacy and persistence of vaccination by detecting the titer of neutralizing antibody. In order to evaluate the effect of vaccination, only the titer of neutralizing antibody produced by the body can be judged.

"However, at present, neutralizing antibody detection is still used as a means to monitor the effectiveness of vaccines, and it is not allowed to carry out neutralization antibody detection activities in other needs, because the vaccination speed is far from enough. Now it is not time to carry out neutralization antibody detection. In the future, with the realization of mass immunization and the smooth development of vaccination work, After the continuous promotion of vaccination and other work and the policy of allowing neutralization antibody detection, the imagination space of the whole market is also very large. " The industry said.

However, there are some doubts about the actual market space of neutralizing antibody detection in the future. Before that, some people in the industry pointed out that neutralization antibody detection was a fake market. If neutralizing antibody detection becomes a market for detecting the effect of vaccine injection in the future, its scale will be huge. However, in the past, the neutralization antibody detection of influenza and other vaccines was only limited to the clinical observation of the vaccine.

It is a false proposition that neutralization antibody detection is widely spread. It is believed that neutralization antibody detection method needs to go through strict standardization process and full performance evaluation, and determine the minimum protection level by determining the appropriate judgment threshold value, establishing the correlation with virus protection. However, new coronavirus mutations continue to occur, from the UK mutation to South Africa mutation to Brazil mutation, and will continue to occur, which strain is the standard will be the most difficult resistance to establish standards. Only when the new coronavirus epidemic is completely controlled, just like influenza, establish a monitoring mechanism and update the epidemic strains every year, we may have corresponding standards.

Undetermined standards and difficult to standardize the kit have become resistance to the promotion of neutralization antibody detection. However, many people from neutralization antibody detection enterprises in South China told the reporter of 21st century economic report that the company has taken the lead in this field, and the new coronavirus epidemic situation and new coronal vaccine are special, and it is difficult to judge the future situation by previous experience.

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