Risk of two vaccinated people catching Covid from meeting indoors is 'tiny'

Sarah Knapton
·3-min read
 Two friends sit on the sea wall  - John Keeble
Two friends sit on the sea wall - John Keeble
Coronavirus Article Bar with counter
Coronavirus Article Bar with counter

The risk of two vaccinated people catching Covid from meeting up indoors is “tiny”, scientists have calculated, with just a one in 400,000 chance of picking up an infection.

Last week, Boris Johnson warned that people should not be allowing others into their homes, even if they had both had the vaccine.

“The vaccines are not giving 100 per cent protection, that’s why we need to be cautious,” said the Prime Minister.

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But Professor Tim Spector, at King’s College London, has calculated that the risk of catching a symptomatic infection is around one in 400,000 for two people who have been vaccinated – which is far less than the risk of developing a blood clot from the AstraZeneca jab.

Prof Spector, who is lead scientist on the ZOE Covid Symptom Study app and professor of Genetic Epidemiology at King’s, said there was currently just a one in 1,400 risk of “bumping into someone” with symptomatic Covid, and people should feel more “relaxed” if they had been vaccinated.

Latest UK vaccine numbers: rollout figures
Latest UK vaccine numbers: rollout figures

Speaking in a situation update video on YouTube, Prof Spector said: The Prime Minister recently told us that two people who had been fully vaccinated really shouldn't meet because it wasn't 100 per cent safe."

“I want to give it some context. It all depends on how much virus is around in the country and currently with rates of one in 1,400 for someone who has been fully vaccinated, according to our data and the trial data, it suggests they are at a 20th of the normal risk, which means their risk is about one in 28,000. 

“So if they’re meeting someone with equally low risk the chance of those giving to each other are really absolutely tiny. 

“So I think this is important to put it into context, because I know many are still worried, still shielding etc. And I think you can be a little bit more relaxed than has been suggested.”

Last week the Medicines and Healthcare products Regulatory Agency (MHRA) said that the risk of developing a blood clot from the Oxford vaccines is around one in 250,000, which they said was a very low risk.

Others have placed the clotting risk at about one in 100,000, once European data has been included.

Statisticians say that a one in 100,000 risk is roughly the same chance of dying under general anaesthesia or in a skydiving jump, or correctly guessing the last five digits of someone’s mobile phone.

Prof Spector added: “The headline news is we’re below 2,000 cases a day, and that’s back to where we were really last July. 

“It’s coinciding with drops in admissions and deaths which are now around the 50 a day mark, which compares to more than 1,000 people a day who are dying of natural causes from other conditions.

“All in all, it’s been a great week, rates have halved. I think it’s all going very well, and I think we can look forward to having a relaxing summer.”

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