New data from an Oxford University trial offer the first evidence that the vaccine COVID-19 developed by the prestigious school together with AstraZeneca can not only prevent people from getting sick with the coronavirus, but it could help to substantially reduce its spread in the community. For the first time in a large-scale human trial, all participants in the UK study were examined at regular intervals for COVID-19 infection after receiving the first injection of the vaccine, rather than just participants who developed suspected symptoms of the disease. .
The Oxford research, published online on Tuesday as a “pre-printed” study yet to be peer-reviewed by The Lancet, found that within 12 weeks of receiving the first dose of the vaccine, there was a 67% reduction in tests among trial participants compared to those who received a placebo.
A series of vaccines, including Oxford / AstraZeneca, the Pfizer and Modern formulas widely used in the USA and others developed around the world have shown strong effectiveness in preventing symptomatic infection, but there has been no evidence so far that anyone could prevent people with the disease without external symptoms.
These asymptomatic carriers have long considered a great risk to transmit the disease to others, feeding its spread within the populations.
For this reason, the latest data from Oxford was received with great enthusiasm by British leaders, who based their hopes on their mass vaccination program mainly on the Oxford / AstraZeneca vaccine. Nearly 10 million people received the first dose of the COVID-19 vaccine in the UK on Wednesday, many with the Oxford injection.
Prime Minister Boris Johnson praised the results as “really encouraging” and expressed his gratitude to the British scientists and national health professionals who drive the UK’s vaccination program, which was one of the first to come into operation in the western world.
UK Health Secretary Matt Hancock also spoke about the “absolutely superb” data from Oxford, telling the BBC on Wednesday that the potential to stem the silent spread of COVID-19 meant that the vaccine would “help everyone us to get out of this pandemic.
12-week dosing gap confirmed
In addition to the evidence on preventing asymptomatic infection, the data released by Oxford scientists on Tuesday reinforced the policy adopted by both Britons and European Union Drug regulators leave an interval of up to 12 weeks between the two doses of the Oxford / AstraZeneca vaccine.
The decision was surprising when the UK regulator announced it shortly before Christmas, despite being the interval recommended by Oxford, as the data available at the time did not clearly demonstrate that the vaccine would remain effective during the interval between vaccines.
But the pre-printed study released on Tuesday showed that the first injection of the vaccine not only remained highly effective (72% from 22 days to 90 days after the first dose), but that leaving at least three months between injections really seemed increase overall effectiveness to 82.4%.
In contrast, in trial participants who received the second dose of the Oxford vaccine after six weeks, the drug’s effectiveness was only about 55%.
The US, the Food and Drug Administration, has not yet granted emergency authorization for the use of the Oxford / AstraZeneca vaccine. Phase 3 human testing is still ongoing in the United States, as well as in the United Kingdom, Brazil and South Africa.
So far, the FDA has shown no inclination to support the longer-range strategy adopted by the UK and Europe if and when it approves the Oxford vaccine, but Britain’s most recent data may influence American regulators.
The head of the Oxford Vaccine Group, Professor Andrew Pollard, who is also the chief scientist for the drug test in the UK, said the data was evidence that the 12-week interval between doses was “the ideal approach for implantation, where people are protected from 22 days after a single dose. “
CBS News producer Steve Berriman contributed to this report.