Photographer: Dhiraj Singh / Bloomberg
Photographer: Dhiraj Singh / Bloomberg
AstraZeneca Plc’s Covid vaccine has been shown to be 82% effective, with a three-month difference between the two photos, according to a new study supporting the UK’s controversial decision to adopt an extended dosing range.
The vaccine can also significantly reduce the transmission of the virus, according to the analysis of data from studies by Oxford University, which developed the shot with the British doctor. Swabs taken from volunteers in the British arm of the study showed a 67% reduction in transmission after the first dose, the report showed.
The UK has approved the administration of the first and second injections of two-dose vaccines four to 12 weeks apart, in an effort to expand scarce supplies while production is accelerating. AstraZeneca executives previously said that the larger difference, compared to the recommended three to four weeks between vaccines for other vaccines, could also increase efficacy.
Covid-19 vaccinations exceed 100 million doses worldwide
The new results are an additional boost to the UK immunization program, which has passed European Union countries and given initial blows to 14% of residents. If the Astra vaccine also reduces transmission, it will speed up the process of achieving herd immunity, when the virus can no longer enter the population.
The effectiveness of the vaccine was increased from 55%, with a dosing interval of less than six weeks to 82%, at a distance of 12 weeks or more, according to the new data. The analysis also found that the shot showed 76% protection after the first of the two injections. This level of immunity was reached 22 days after the first blow.
The AstraZeneca vaccine has shown an average protection of 70% in previous results of extensive clinical trials. These results came from two subsets, one of which provided 62% efficacy, the other 90%, with different dosage levels in the two groups. When the UK approved the vaccine in December, regulators said they thought the discrepancy was more likely to be related to the interval between photos than the dosage level.
More cases
Initial results were based on 131 cases of symptomatic Covid-19 in studies, a number that has since increased to 332, allowing for more in-depth analysis. The new data is based on information from more than 17,000 study participants in the UK, Brazil and South Africa, Oxford said.
The European Union also approved the vaccine, with France, Germany and other countries restrict its use to the elderly, citing a lack of data on studies in older age groups.
“These new data provide important insight into the interim data that has been used by more than 25 regulators,” said Andrew Pollard, Oxford’s chief investigator and co-author of the paper, in a statement. He also supports the policy recommendation made by the UK vaccine advisory group, he said.
Oxford also intends to publish data on how the vaccine interacts with the new vaccine variants of coronavirus in the following days. The university said it expects the results to be consistent with those of other developers.
Moderna Inc. said last month that his vaccine would protect against two known variants of the coronavirus, but plans to begin human studies on a booster shot for a South African strain that can cause immunity to drop faster. Pfizer Inc. also seeks to develop a booster shot.
– With the assistance of Stephanie Baker
(Updates with more data in the report starting with the fourth paragraph)