Researchers from the University of Oxford have published results from ongoing trials on the Oxford/AstraZeneca COVID-19 vaccine, revealing the efficacy when doses are spaced out and the effect that it has on transmission.
In a pre-print paper in The Lancet, the team looked at the efficacy of the vaccine when doses are spaced out by 12 weeks, as is happening in the UK as the government attempts to stretch out supplies and get as many first doses out as possible. In a boost to the immunization strategy, the interim results show that a single dose of the vaccine is 76 percent effective from three to 12 weeks. When a second dose was given after a space of 12 weeks or more, efficacy rose to 82.4 percent.
The part that has immunologists and epidemiologists tentatively excited, however, is that the vaccine can potentially significantly reduce transmission of the disease. COVID-19 tests of UK volunteers in the trial showed that it reduced positives by 67 percent. A larger sample is needed, but the results indicate there's good reason to believe that transmission can be cut by the vaccine, and the pandemic spread slowed.
Reacting to the news, UK Health Secretary Matt Hancock told BBC News that the study shows vaccines are "the way out of this pandemic".
“We now know that the Oxford vaccine also reduces transmission and that will help us all get out of this pandemic,” Hancock told BBC Breakfast, adding that the study should “give everyone confidence that this jab works not only to keep you safe but to keep you from passing on the virus to others.”
Though the results are exciting, others urged caution from the public.
“While this would be extremely welcome news, we do need more data before this can be confirmed," Dr Doug Brown, chief executive of the British Society for Immunology told the New York Times. "So it’s important that we all still continue to follow social distancing guidance after we have been vaccinated."
The study, which has not yet been peer-reviewed, found no hospitalizations or severe cases of the disease 22 days after the first dose has been administered.
“This primary analysis reconfirms that our vaccine prevents severe disease and keeps people out of hospital," Sir Mene Pangalos, executive vice president of BioPharmaceuticals R&D, said in a statement. "In addition, extending the dosing interval not only boosts the vaccine’s efficacy, but also enables more people to be vaccinated upfront. Together with the new findings on reduced transmission, we believe this vaccine will have a real impact on the pandemic.”
The vaccine has the advantage over other vaccines in that it can be stored at 2-8°C (36-46°F). This means it can be kept in standard refrigerated conditions, and transported much more easily than vaccines that require ultra-cold storage.
AstraZeneca is now looking for an emergency use listing from the World Health Organization in order to roll out the vaccine to lower income countries and is keen to emphasize it is not seeking profit for the vaccine during the pandemic.
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