Lockdown ‘reducing number of people infected by someone with coronavirus’
The UK lockdown could be driving down the number of people one person who has coronavirus infects, research suggests.
The London School of Hygiene and Tropical Medicine estimates that before the lockdown one positive person would infect 2.6 other people.
But it says measures introduced by the UK Government mean that number could now be just 0.62.
A study by the school describes this number as the reproduction number – the average number of people who will catch a disease from a single infected person.
Experts say that maintaining this figure below one means the epidemic will decline.
In an online survey (CoMiX) the research team asked 1,300 individuals to list their contacts for the previous day.
This was compared with a similar study from 2005-2006 (Polymod) which researchers used as a measure of the number of contacts people would have had prior to the lockdown.
Using the change in contact patterns, the team calculated a change in reproduction number between the pre-lockdown – Polymod – and post-lockdown – CoMix.
Researchers found that the mean number of contacts per person measured was 73% lower now than before the lockdown.
This suggests that the reproduction figure now would be between 0.37 and 0.89 with the most likely value being 0.62.
Professor John Edmunds, from the London School of Hygiene and Tropical Medicine, who led the research, said: “If we see similar changes across the UK population, we would expect to see the epidemic to start to decline.
“However, our estimates are not to be read as ‘job done’.
“Rather, they should be used as motivation for us all to keep following UK Government instructions. It’s imperative we don’t take our foot off the pedal.
“We must continue to stop transmission of the virus to reduce the burden on the NHS now and over the coming months.”
The researchers acknowledge limitations of their work, which has not been peer-reviewed – including the assumption that contact patterns from 2005-06 are similar to those in 2020.
However, a more recent study carried out by the BBC shows similar contacts patterns in all but ages 13-17.
Researchers also could not directly measure the contacts between children and adults, and, because individuals also reported their contacts on the previous day, they may not have remembered them all.