“Over the period of the lockdown, we have been in level four, and thanks to your sacrifice we are now in a position to begin to move in steps to level three.” Johnson said the UK was currently under the second highest level of threat, but the situation was improving. A country may see regional variations in its R number, depending on local factors like population density and transport patterns. It depends on the biology of the virus people's behaviour, such as social distancing and a population’s immunity. The reproduction number is not fixed, though. That means each person would pass it on to between two and three people on average, before either recovering or dying, and each of those people would pass it on to a further two to three others, causing the total number of cases to snowball over time. Anything below 1 and an outbreak will fizzle out – eventually.Īt the start of the coronavirus pandemic, the estimated R for coronavirus was between 2 and 3 – higher than the value for seasonal flu, but lower than for measles. For an R of anything above 1, an epidemic will grow exponentially. It’s the average number of people on to whom one infected person will pass the virus.
R, or the 'effective reproduction number', is a way of rating a disease’s ability to spread.
