The transmission is reduced by 67 percent after the first dose of the vaccine, according to an analysis of swabs obtained from UK volunteers.
In a paper currently under review at medical journal The Lancet, researchers say that a single standard dose of the vaccine is “76 percent effective at protecting from primary symptomatic COVID-19 for the first 90 days post vaccination, once the immune system has built this protection 22 days after the vaccination, with the protection showing little evidence of waning in this period.”
Oxford scientists also found that a booster dose given 12 weeks after the first jab increases the efficacy to 82.4 percent, with indications that leaving a longer gap between doses increases effectiveness.
Really encouraging data from a new study today shows the Oxford/AZ vaccine provides significant protection against the virus.
I’m incredibly grateful to all our scientists, NHS staff and volunteers working on our vaccination programme. https://t.co/NZwXJ4W5pp
Prime Minister Boris Johnson hailed the results as “really encouraging.”
“I’m incredibly grateful to all our scientists, NHS staff and volunteers working on our vaccination programme,” he wrote on Twitter.
Health Secretary Matt Hancock also expressed gratitude to the teams at Oxford University and the British-Swedish pharmaceutical firm AstraZeneca, adding that “vaccines are the way out of this pandemic & we are making fantastic progress vaccinating the most vulnerable.”
The Oxford/AstraZeneca vaccine, along with the Pfizer/BioNTech jab, are already being rolled out across the UK.
The vaccine developed by U.S. firm Moderna has also been approved but is not yet in use.
By Tuesday, more than 9.6 million people had received a first dose of a COVID-19 vaccine, with 496,796 people having also had a booster shot.
On Tuesday 02 February 2021, 16,840 new cases and 1,449 deaths within 28 days of a positive test were reported across the UK.
— Public Health England (@PHE_uk) February 2, 2021
The European Medicines Agency has also authorised the Oxford/AstraZeneca vaccine for use in all adults throughout the European Union.
However, health authorities in Germany and other countries have raised concerns that the firm didn’t test the vaccine in enough older people to prove it works for them, and indicated they would not recommend it for people over 65.
French President Emmanuel Macron said Tuesday that his country will only administer the jab to people under the age of 65.
The Associated Press contributed to this report.