COVID-19: Adenovirus vector vaccine faces technical challenge

COVID-19: Adenovirus vector vaccine faces technical challenge.  Many countries suspend AstraZeneca’s COVID-19 vaccination, adenovirus vector technology route is facing test.

Due to adverse reactions such as thrombosis and coagulation abnormalities in vaccinators, 20 countries have suspended the adenovirus vector vaccine vaccination jointly developed by AstraZeneca/Oxford University.

On March 15, the WHO stated that the WHO Global Vaccine Safety Advisory Committee has been reviewing the existing data on the vaccine and is in close contact with the European Medicines Agency to discuss the issue on March 16.

According to data from the European Center for Disease Control and Prevention on the 14th, there are currently nearly 8 million doses of AstraZeneca vaccine in Europe that have not been used.

Many parties are cautious about the safety of AstraZeneca vaccine

Although France announced the suspension of AstraZeneca’s COVID-19 vaccination, according to a report by Reuters on March 16, French vaccination chief Alain Fischer said that AstraZeneca’s suspension of vaccine production is temporary and emphasized that The number of cases of adverse side effects of the vaccine is very small.

On March 11, the European Medicines Agency stated that so far, 5 million people in Europe have been vaccinated with AstraZeneca’s COVID-19 vaccine, and 30 cases of “thromboembolic events” or blood clots have been reported. The European Medicines Agency said that there is currently no indication that the above-mentioned adverse reactions are caused by the vaccine, and the “benefits of the COVID-19 vaccine still outweigh the risks”.

It is worth noting that the British regulatory agency emphasized that the AstraZeneca vaccine has been “rigorously tested.” There is currently no evidence that vaccination is directly related to blood clots.

AstraZeneca has also previously stated that a review of the data of people who have been vaccinated against the COVID-19 vaccine has found no evidence to increase the risk of pulmonary embolism, deep vein thrombosis or thrombocytopenia.

Adenovirus vector technology route tested

AstraZeneca/Oxford’s COVID-19 vaccine is an adenovirus vector vaccine. The vaccine of this technical route is to make harmless adenoviruses wear the “hat” of the S protein, the key key for the COVID-19 virus to invade human cells, to make the body produce immune memory and stimulate the body Produce antibodies.

From the perspective of global COVID-19 vaccine research and development, Johnson & Johnson, Kangsino (399.820, -3.36, -0.83%) biological COVID-19 vaccines also belong to the technical route of adenovirus vectors, and the difference is viral vectors.

• Johnson & Johnson’s COVID-19 vaccine is based on the company’s Ad26 adenovirus vector. The Johnson & Johnson COVID-19 vaccine has not been exposed to adverse reactions such as thrombosis.
• Kangxinuo Bio-COVID-19 Vaccine uses Ad5 adenovirus as a carrier,
• According to AstraZeneca’s global official website, its COVID-19 vaccine is a replication-deficient chimpanzee virus vector based on a weakened version of the common cold virus (adenovirus).

In other words, because the specific viral vectors are different, the current adverse reaction of a certain adenovirus vector vaccine does not mean that the vaccine of the entire technical route is no longer safe.

At the end of February this year, Chen Wei, an academician of the Chinese Academy of Engineering, who participated in the development of China’s first adenovirus vector vaccine for COVID-19, emphasized in an interview with CCTV News that up to now, the vaccinated population includes people in an extreme environment, and no vaccine related has been found. There are no special adverse reactions that are different from other vaccines.

(source:internet, reference only)

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