The reproductive number or R-value of coronavirus transmission across the UK ranges between 1 and 1.4, the Government Office for Science and the Scientific Advisory Group on Emergencies (Sage) said.
When R was last updated on December 23, 2020, it was between 1.1 and 1.3.
R stands for the average number of people that each Covid-19 positive person will infect.
When the number is above 1, a breakout can grow exponentially.
An R number between 1 and 1.4 means that, on average, every 10 infected people will infect between 10 and 14 other people.
Sage said the estimates released on Friday represent the transmission of Covid-19 in the past few weeks rather than the current situation.
This is due to the time lag between infection, symptoms, and the need for medical attention.
The estimates for R and the growth rate are provided by the Scientific Pandemic Influenza Group on Modeling (SPI-M), a subgroup of Sage.
The growth rate, which estimates how quickly the number of infections changes from day to day, is between 0 and plus 6% for the whole of the UK.
This means that the number of new infections increases by 0 to 6% every day.
Estimates for R and growth rates are shown as a range, and experts believe that the true values are within that range.
Scientists advising the government said the estimates of R and growth rates are based on the most recent data available through Jan. 4.
Sage said, “R is a lagging indicator and so these estimates cannot take into account the impact of recent policy changes or changes in transmission that have not yet been reflected in epidemiological data.
“This includes any changes that may have occurred during the festive period or the UK lockdown announced on January 5th.”
The experts said the novel coronavirus variant is growing much faster than other variants currently circulating in the UK and that it will take longer to fully understand the full effects of the new variant on the R number.