About 1,500 volunteers in the Covid-19 Oxford / AstraZeneca vaccine clinical trial were not immediately informed of the wrong dose, by mid-2020.
After detecting the error, the company did not issue an official notice but only explained to the volunteers via a letter, sent on June 8, 2020, signed by Professor Andrew J. Pollard of Oxford. . The case is fine Reuters recent investigation.
The test participants received only about half the dose because the Oxford experts miscalculated. However, in the letter, the scientists did not admit any mistakes. They also did not say they had reported the incident to the British health authority, which then recommended Oxford giving a sufficient dose to another group of volunteers to control.
Many people expect vaccines developed by the UK. Vaccine doses are being shipped across the country as an affordable anti-epidemic tool. The Oxford vaccine was then under scrutiny due to problems in the clinical trial as well as the scant data on its efficacy in the elderly.
Reuters shared a letter they got from university with three medical ethics experts. This suggests that the Oxford team may not have been transparent with volunteers. Usually, test participants need to be fully informed of any changes.
Arthur L. Caplan, founder of the Medical Ethics Department at New York University, said: “They are not clear about what’s going on, what they know, the rationale for doing further research. All were buried in the information-dense storm.
Steve Pritchard, an Oxford spokesman, said: “It is true that the half-dose injection incident was out of plan. But we already knew the difference in dose measurements, and discussed this with regulators before the amendment. We do not make a mistake when using the vaccine “.
He said the incident did not cause the vaccine results to contradict the data released by partner AstraZeneca last year. The UK Health Research Service said the vaccine dose adjustment was approved by the ethics committee, only volunteers will later know it.
ChAdOx, Covid-19 vaccine of AstraZeneca / Oxford is formulated based on virus vector technology, using harmless flu virus from chimpanzees. Viruses contain genes from nCoV. When injected into human cells, they create proteins that help the immune system recognize and respond to pathogens in the future.
On November 23, 2020, the pharmaceutical company AstraZeneca and the University of Oxford announced that the ChAdOx vaccine is 90% effective depending on the dose. This is the third “candidate” to show positive results in large-scale phase 3 trial. Although not as effective as the products of two competitors Moderna and Pfizer, the Oxford vaccine is low priced and easier to transport and store.
Vaccine protection ranges from 62-90%, depending on the dose administered. There were two different vaccine regimens in the trial. In the first regimen, volunteers receive half of the dose, then at least a month are injected with the full dose, reaching 90% efficiency. The second regimen injected two full doses one month apart, achieving 62% efficiency. The average efficacy of the two regimens was 70%.
The trial used a control group and placebo as the meningitis vaccine. This ensures that volunteers who do not receive ChAdOx still have common side effects such as low-grade fever, muscle aches, and biceps. AstraZeneca gave the initial analysis after 131 volunteers were infected with nCoV. According to the company, none of them developed abnormal symptoms or required hospitalization.
On February 1, Vietnam officially approved the AstraZeneca / Oxford vaccine. The contract to supply 30 million doses of Covid-19 vaccine signed by AstraZeneca with Vietnam Vaccine Joint Stock Company (VNVC). It is expected that the vaccine will be brought to Vietnam in the first half of 2021. Mr. Ngo Chi Dung, General Director of VNVC said that the price of this vaccine has not been determined yet, the costs are being calculated at a “very reasonable price. “tailored to people’s needs. The distribution of this vaccine also depends on the use plan of the Ministry of Health.
Thuc Linh (According to the Reuters)