Expert: China's SARS-CoV-2 vaccine may only have 40% efficacy

Reporter : Tang Di  /  Editor: Yun Tao / Publisher : New Tang Dynasty Television

Ref : https://www.ntdtv.com/gb/2020/09/01/a102931329.html

Translation, editing : Gan Yung Chyan. KUCINTA SETIA

Image : Schematic diagram of the SARS-CoV-2 vaccine. (Image by PixxlTeufel from Pixabay)

A number of SARS-CoV-2 (covi, in short, novel coronavirus) vaccines developed by the United Kingdom, the United States, China, Russia and other countries have recently announced that they have entered the third phase of human clinical trials. Some experts pointed out that the vaccines developed by Russia and the CCP are all based on the common cold virus adenovirus type 5 (Ad5), and there are key flaws that may significantly reduce the actual effect of the vaccine. However, the CCP's Phase III trial of this defective vaccine has not yet been completed, and its research and development company has recently begun negotiations with many countries to try to promote the use of the vaccine in other countries in advance. Experts say this will bring serious public health risks.

According to a report published by "Reuters" a few days ago, the covi vaccine Ad5-nCoV, jointly developed by CanSino Biologics and the Chinese military, has been approved by the Chinese military for military use, but this vaccine is actually is an improved product of the common cold virus type 5 adenovirus (Ad5). Another vaccine developed by the Gamaleya Institute, a Russian state-run research institution, is also composed of Ad5 and Ad26 adenoviruses. Both of the first two vaccines launched by China and Russia have key flaws.

The report pointed out that the way a vaccine developed based on Ad5 adenovirus works in the human body is to use a harmless virus as a "vector" to deliver genes from the target virus (CCV) to human cells, thereby initiating an immune response against the actual virus. . However, because Ad5 adenovirus is a common cold virus, many people may have already produced Ad5 antibodies. Therefore, when using vaccines developed based on Ad5 adenovirus, Ad5 antibodies already in the body may cause the immune system to attack the vector. Instead of reacting to covi itself, the effectiveness of these vaccines is greatly reduced.

The report quoted Johns Hopkins University vaccine researcher Dick Durbin as saying, "The reason Ad5 worries me is that many people are immune. I'm not sure what their strategy is... Maybe it will not have 70% efficacy, it may only have 40% efficacy, which is better than nothing until a new vaccine appears."

Zhou Xing, a researcher at McMaster University in Canada, pointed out that the high-dose Ad5 vector in the CanSino vaccine may cause fever in humans and exacerbate people's doubts about the safety of the vaccine.

Recently, many countries around the world have seen an increase in the rebound of the covid epidemic. Just last Sunday, a Shanghai medical expert disclosed to mainland Chinese media that their latest study found that covi does have an antibody-dependent enhancement (ADE) phenomenon, and the proportion is not low, which means that the SARS-CoV-2 vaccine is immune. The reaction may cause covid pneumonia to worsen. But less than a day after the report was published, it was forced to retract it.

The Ad5-nCoV vaccine, developed under the leadership of the Chinese military and Chinese pharmaceutical company CanSino, has just entered Phase III clinical trials less than half a month ago. Its safety and effectiveness are still questioned by international virology experts, but in order to seize the international market, CanSino has already begun negotiations with several countries to seek urgent approval from the governments of these countries to use the Ad5-nCoV vaccine developed by the company.

In addition, just about two weeks ago, Russia also approved the use of a vaccine developed by the country’s research institutions that has not undergone the third phase of testing.

This practice of the Russian government, and the aforementioned practice of China CanSino, are both considered to be cheating in the international vaccine research and development competition. International medical experts worry that once a vaccine similar to cheating is widely used internationally, it is likely to aggravate the disease, even worse than not being vaccinated.

The Voice of America reported that this move by CanSino has once again heated up the global covid vaccine development competition. Some public health experts pointed out that vaccinating people with the experimental vaccine developed by CanSino before the completion of large-scale clinical trials may bring serious public health risks.

According to the report, given that vaccines must be used in a large number of healthy people who are not infected with the virus, as an international practice, before the completion of large-scale trials, almost no vaccine has been approved for widespread use in the public.

The report quoted Lawrence Gostin, a professor of global health law at Georgetown University, as saying that CanSino’s actions “broke all global conventions around science and ethics and are a huge gamble”.

In addition, according to a report by the Chinese mainland media CBN, CanSino Bio made an announcement on the Hong Kong Stock Exchange on 18 August, announcing that the company had received "a recombinant human replication-deficient adenovirus as a vector on 11 August. The “Novel Coronavirus Vaccine” is a notice of invention patent granted, which was jointly applied by the Chinese Military Academy of Military Sciences and the company.

The announcement also acknowledged that the Phase III clinical trial of the recombinant novel coronavirus vaccine (Ad5-nCoV) that the company participated in the research and development at that time had not yet entered the group.

The announcement stated that “the safety and effectiveness of the recombinant novel coronavirus vaccine Ad5-nCoV must be confirmed by clinical studies, and the company cannot guarantee that it will eventually successfully develop or commercialize Ad5-nCoV.”