Single vaccine shot slashes transmission as well as infection, new study finds

A single dose of a Covid-19 vaccine can slash transmission of the virus by up to half, according to a new Public Health England study.

The research provides further evidence of the merits of vaccination. As well as the strong protection against illness, vaccinated people (who develop an asymptomatic infection) are far less likely to pass the virus on to someone else. 

The PHE study found that people who became infected with coronavirus at least three weeks after receiving one dose of either a Pfizer or AstraZeneca vaccine were between 38 and 49 per cent less likely to pass the virus on to others living in their homes, compared to those who were unvaccinated.

The research involved over 57,000 volunteers from 24,000 households who were living with a vaccinated person. Results were compared with nearly one million people living with those who had not had a vaccine. Contacts were considered to have developed a secondary case of coronavirus if they tested positive two to 14 days after the initial household case.

The study also found that a single shot of either vaccine reduces the risk of developing any infection by 60 to 65 per cent. Protection was seen from about 14 days after vaccination, with similar levels regardless of a person’s age.

Professor Peter Openshaw, a member of the Covid-19 clinical information network, said the results are “very, very reassuring” and “certainly better than many of us expected just a few months ago”.

Matt Hancock, the health secretary, has described the study as “the most comprehensive real-world data showing vaccines also cut transmission of this deadly virus… It further reinforces that vaccines are the best way out of this pandemic.”

Over 40s will be invited to book their jabs by the end of this week and new analysis from The Times reveals the extent to which vaccinations are driving down cases of Covid-19 across much of the country.

More than 38 million people in England are now living in areas that are recording virtually no new cases of Covid. The Times analysis splits England into 6800 areas, each with an average population of around 8200. In just over 4800 areas where these 38 million people are living, two, one or no new cases of Covid were reported in the last week. 

Almost 70 per cent of the adult population now have antibodies – up from 54.9 per cent from two weeks ago, according to the ONS figures published today.

And, perhaps most encouraging of all, deaths involving Covid-19 in England and Wales have now fallen by 97 per cent since the peak of the second wave.