COVID Threat Growing as England's R Number Continues to Go Up

Zarrin Hossain

December 07, 2021

In England, with the total number of confirmed cases of the new Omicron variant of SARS-CoV-2 rapidly rising, the COVID reproduction number (R) continues to increase.

The R number became a defining measure at the start of the pandemic when  Prime Minister Boris Johnson told the public on May 10, 2020 that easing lockdown in England would depend on whether the reproduction number could be kept down. The R number indicates the average estimate of the number of COVID transmissions from one infected individual to another.

On Friday, December 3, the UK Health Security Agency (UKHSA) reported the latest COVID estimates to be between 0.9 and 1.1. This means that on average, every 10 people who have been infected will produce between 9 to 11 secondary infections – a rise from previous week, which saw figures between 0.8 and 1.0.

Despite the increase in the R number and the rising number of Omicron variant cases, Boris Johnson is hesitant to go into another full lockdown. "We’re trying to take a balanced and proportionate approach to the particular risk posed by Omicron," he said in press conference last week, "We haven’t ruled out Plan B, another lockdown of the kind we have had before is extremely unlikely."

"Although cases remain high or high-ish, you’re seeing a decline in the number of admissions to hospital and a decline in the number of deaths," he added.

"We will change things as necessary but we’re looking for the first real reassurance we need that the vaccines are efficacious against this variant. Even if the efficacy is reduced, it’s still very important to know if they’re effective or not."

Growth Rate Also Increasing

London and East of England show transmission estimates between 0.9 to 1.2, while the South-East region demonstrates the highest R-rate between 1.0 to 1.2.

The growth rate, the daily speed at which COVID infections grow, has also risen. The latest growth rate is estimated to be between -1% and +1%, compared to previous week figures which were between -2% and 0%. Although lower than previous weeks, this suggests that the number of new infections remain at a stationary level, but daily cases can spread rapidly by up to 1% or shrink by 1%.

Both of these key measures indicate that the COVID pandemic is growing. The higher the R number is above 1.0, the greater the transmission from one infected individual. Similarly, a growth percentage greater than +0% also becomes a cause for concern.

While many countries consider these precautionary measures when evaluating the changing restrictions, it is possible for the R number and growth rate to change over time, but caution needs to be taken by following the mandatory rules set by the government.

"With winter upon us and the threat of the new Omicron variant unknown, it is important we do everything we can to protect ourselves," says Dr Mary Ramsay, head of immunisation at UKHSA.

"Booster doses have been shown to provide at least 93% protection against severe disease, so it is vital everyone takes up the offer when they become eligible," said Dr Ramsay.

"Day-to-day actions such as wearing masks in shops and on public transport, washing our hands regularly, and meeting others in well ventilated places, can also significantly reduce the risk of catching or passing on the virus, including the new variant."


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