"Russian and Chinese Vaccines Likely Ineffective... Based on Already Circulating Virus"

Russia-China Vaccines Based on Adenovirus Type 5, Widely Used in Flu Vaccines
Many Antibody Holders Already... Over 80% Antibody Presence in Africa
Weakens HIV Virus Response... Poses Greater Risk in Africa

[Image source=Reuters Yonhap News]

[Asia Economy Reporter Hyunwoo Lee] There are claims in the scientific community that the novel coronavirus disease (COVID-19) vaccines approved by Russia and China without undergoing Phase 3 clinical trials may struggle to demonstrate proper efficacy. Both vaccines are based on adenovirus type 5 (Ad5), which has been widely used in flu vaccines, meaning many people already have immunity, leading to analyses that their effectiveness will be very limited. Moreover, there are warnings that these vaccines could weaken immune responses against the human immunodeficiency virus (HIV), so residents of some African countries where HIV is highly prevalent should be cautious about vaccination.

According to the UK Guardian and major foreign media on the 31st of last month (local time), the COVID-19 vaccine developed by Russia's Gamaleya Institute and approved by Russian authorities, as well as the COVID-19 vaccine developed by China's CanSino and patented by Chinese authorities, were developed based on Ad5, which has already been widely used in flu vaccines. The scientific community estimates that since about 70% or more of the global population?including about 40% of Americans and Chinese and over 80% of Africans?have immunity to Ad5, the efficacy of these vaccines will not be significant. Anna Durbin, a vaccine researcher at Johns Hopkins University, explained, "I don't really understand their strategy. The immune efficacy of these vaccines is at most about 40%, which is better than nothing but not very effective."

Ad5 is a virus that has been used as a basis for various vaccines such as flu and pneumonia vaccines since the 1970s. It is genetically engineered in the lab to be replication-deficient, and viral information aimed at inducing antibody formation is inserted into Ad5, which acts as a so-called 'vector' to induce antibody formation against the target virus. Since it has already been widely used and administered, it is analyzed that it is not easy to induce antibody formation against the COVID-19 virus within the body.

Some concerns have been raised that these vaccines might actually reduce immunity against the HIV virus, making residents of some African countries where HIV is prevalent more vulnerable if vaccinated. Dr. Larry Corey, head of the U.S. COVID-19 Vaccine Prevention Network, stated, "I am worried about using such vaccines in countries where people are easily exposed to and at risk of contracting HIV." He emphasized that more clinical research on these side effects should be conducted before use.

Dr. Zhoushing from McMaster University in Canada explained, "Ad5-based vaccines carry side effects that can cause high fever and have the risk of triggering excessive immune responses," adding, "Compared to the Ad5-based vaccine developed by CanSino, the vaccine jointly developed by AstraZeneca and Oxford University has more advantages."

The vaccine jointly developed by AstraZeneca and Oxford University is known to have entered large-scale clinical trials in the United States. According to Bloomberg, AstraZeneca announced that the vaccine they are co-developing with Oxford University has begun large-scale Phase 3 clinical trials in the U.S. AstraZeneca stated, "Vaccinations of volunteers started on the 29th of last month," and "From the 7th, we plan to vaccinate 50 people per day." AstraZeneca had previously announced that the clinical trial would involve about 30,000 participants in the U.S.

This content was produced with the assistance of AI translation services.