Drug manufacturer AstraZeneca and Oxford University on Wednesday said that a manufacturing error has raised concerns about the preliminary results of their vaccine candidate, reported AP. The problems in the drug’s efficacy that could arise due to this error is still unclear.
The drug manufacturer on Monday said that its potential coronavirus vaccine, which is being developed with Oxford University, has shown more than 70% overall efficacy in a third phase interim trial.
A group of volunteers in the AstraZeneca trial received a lower dose of the vaccine candidate than the others who got two full doses. In the lower dose group, AstraZeneca said that the vaccine appeared to be 90% effective. For those who took two full doses, the vaccine was just 62% effective. In combination, the vaccine turned out to be 70% effective, the drug maker said.
Monday’s announcement of the partial results were based on ongoing studies in the United Kingdom and Brazil that were trying to establish the optimal dosage, the efficacy, and safety aspects. In a statement on Wednesday, Oxford University said that some of the vials did not have the right vaccine concentration, which led to a few of the volunteers receiving a half dose. The university also said it had spoken to regulators, and decided to complete the late-stage trial with two groups. The manufacturing was corrected, AP reported, citing a statement.
“The reason we had the half-dose is serendipity,” said the head of AstraZeneca’s non-oncology research and development, Mene Pangalos, reported Reuters. Pangalos said they decided to check once they noticed side effects like fatigue and headache among some of the participants. The company then planned to continue with half dose and administer the full shot at a scheduled time.
However, experts said that a relatively small number in the low dose group will make it difficult to ascertain the actual efficacy of the vaccine candidate or a statistical anomaly. Around 2,741 people received half the dose, followed by a full one, the company said. On the other hand, 8,895 people received two full doses of the vaccine candidate.
During Monday’s announcement, Oxford University said that the partnership hopes to supply 3 billion doses of the vaccine across the world by the end of next year. It added that the vaccine would be a “low cost” one and that it can be stored at refrigerator temperatures and deployed “quickly using existing infrastructure”.
Serum Institute of India Chief Executive Officer Adar Poonawalla welcomed the announcement. His company has teamed up with AstraZeneca, the Gates Foundation and the Gavi vaccine alliance to produce more than a billion doses of the Covid-19 vaccine for global supply.
Vaccines in the mix
The vaccine being developed by AstraZeneca and the Oxford University is expected to be cheaper and easier to transport and store compared to those of Moderna and Pfizer, though the latter two have shown higher rates of efficacy at 94.5% and 95%, respectively.
The Moderna vaccine may be priced between $25 (approximately Rs 1,854) and $37 (approximately Rs 2,744) per dose, depending on the amount ordered by governments, the company’s CEO said.
India has not signed a deal for a coronavirus vaccine yet so it is unclear when it will be available for use in the country, despite some leaders promising it will be available from as early as January. Availability of the vaccine in India will be subject to approval by domestic regulators, and the Indian government agreeing to purchase them. So far, many other nations including the United States, United Kingdom, the European Union, Australia and Israel have made deals to buy millions of doses of the vaccines.