Big problems soon surfaced.
An AstraZeneca executive told Reuters on Monday that the company did not intend to get half the dose for any of the participants. The British researchers conducting the trial there initially wanted to give the full dose to the volunteers, but the miscalculation meant that they were mistakenly given only half the dose. Executive, Menelaus Pangalos described the error as “condemnation”, allowing researchers to stumble upon more promising dosing practices.
Many outside experts, who denied the reliability of the results, because the recently calibrated clinical trials were not designed to test how well the initial dose of half-strength worked.
The contingency nature of the discovery was not mentioned in the company’s initial announcement.
In a statement thanking Oxford, AstraZeneca spokeswoman Ms. Maxwell said that with how many of the vaccines were produced from the dose, the issue that has been resolved was an error.
Then, on Tuesday, the head of Operation Operations, Mon Nusf Sloui, USA, noted another limitation in AstraZeneca’s data, a U.S. initiative for a fast-track coronavirus vaccine. In a call with reporters, he suggested that participants receiving the initial dose of half-strength are 55 years of age or older. Ms. Maxell declined to say whether that was the case, noting that the data would soon be published in a peer-reviewed journal.
If the initial half-strength dose was not tested in older participants, who are particularly vulnerable to Covid-19, it weakens the case of AstraZeneca for the employer that the vaccine should be authorized for immediate use.
One way coronavirus vaccine
Learn words about the vaccine
Confused by all the technical terms used to describe how the vaccine works and is tested? Let’s help:
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- Adverse event: A health problem that occurs in volunteers in a clinical trial of a vaccine or drug. Improper occurrence does not always occur due to the treatment tested in the trial.
- Antibody: A protein made by the immune system that can bind to pathogens such as coronavirus and infect cells.
- Approval, license and authorization of emergency use: Drugs, vaccines and medical devices cannot be sold without earning in the United States Approved From the Food and Drug Administration, known as Licensor. After the company considers the results of a clinical trial before the FDA, the agency determines whether the product is safe and effective, a process that usually takes several months. If the country is facing a crisis – like an epidemic – a company can apply instead Emergency use authorizationIs, which can be given very quickly.
- Background rate: How often does a health problem known as an adverse event occur in the general population? To determine if a vaccine or drug is safe, the researchers compare the rate of adverse events in the trial with the background rate.
- Efficacy: A measure of how effective the treatment was in the clinical trial. For example, to test the coronavirus vaccine, researchers compared the number of people in the vaccine and placebo groups who received Covid-19. The real-world effectiveness of a vaccine may differ from its effectiveness in trials.
- Phase 1, 2, and 3 trials: Clinical trials usually take place in three stages. Phase 1 trials typically involve a few dozen people and are designed to monitor whether the vaccine or drug is safe. The Phase 2 trial, involving hundreds of people, allows researchers to try different doses and collect more criteria about the effect of the vaccine on the immune system. Phase 3 trials, involving thousands or tens of thousands of volunteers, to determine the safety and effectiveness of a vaccine or drug, to see how many people are designed to fight the disease are safe.
- Placebo: A substance that has no therapeutic effect, often used in clinical trials. To see if a vaccine inhibits covid-19, for example, researchers could vaccinate half of their volunteers, while the other half received a saltwater placebo. They can then compare how many people in each group are infected.
- Post Market Surveillance: Monitoring that occurs after a vaccine or drug has been approved and is regularly prescribed by doctors. This surveillance specifically confirms that the treatment is safe. On rare occasions, it detects side effects in some groups of people who missed out during a clinical trial.
- Pre-research: Studies conducted before the start of a clinical trial, typically involving experiments where treatment is performed in cells or animals.
- Viral vector vaccines: A type of vaccine that uses a harmful virus to fight off immune-system-stimulating agents in the human body. The viral vector is used in several experimental Covid-19 vaccines, including those developed by AstraZeneca and Johnson & Johnson. Both companies use a common cold virus adenovirus as their vector. Adenovirus contains coronavirus genes.
- Trial protocol: A series of procedures to be performed during a clinical trial.
Stephanie Como, a spokeswoman for the Food and Drug Administration, declined to comment on whether the dosing error would harm the chances of the vaccine being authorized. The FDA said it expects the vaccine to be at least 50 percent effective in preventing or reducing the severity of the disease, which appears to have been cleared even in the group receiving two full doses of the vaccine.
Shares of AstraZeneca fell nearly 5 percent this week, while the Broader Stock Index hit a record high. Investors appear to be disappointed with the condemnable results, especially in the race for the coronavirus vaccine, compared to more explicit data released by Ast Strazeneka’s two main rivals.
