After the lockdown and reintroduction of the tiered system, infection rates could rise again, Sage experts have warned.
Scientists from the Emergency Scientific Advisory Group have stated that going back to the previous tiered system could cause infections to rise back to early November levels.
Lockdown measures currently in progress in England are likely to bring the coronavirus R number below one, it is said – but they are set to end on December 2nd.
And the ability to revert to the previous tiered system before the second lockdown may not be enough to keep the rate down, the scientists say.
A November 4th document from the group states: “If England returns to the same tiering application before November 5th, transmission will return to the same rate of increase as it is today.”
In a series of new documents released by the group on Friday, the experts said hospital admissions and deaths could fall until at least the second week of December if the four-week lockdown measures are followed.
However, they said the longer-term outlook is less certain.
They say the fortune will depend on both the type of non-pharmaceutical interventions carried out after December 2nd and government policies during the holiday season.
Another Sage document suggests that the national outbreak is still in a “high and controlled” phase.
And this could have a significant impact on all of us in the coming weeks.
Sage says if it continues, or if the outbreak returns to current levels after the lockdown, there is “little to no leeway for relaxing social distancing rules over Christmas”.
However, if the prevalence is “low and controlled” and R is “well below one” for some time, there may be “greater potential for relaxation of social distancing rules for a limited period during the holiday season”.
Government scientists also said that if R – the reproductive number for coronavirus – is reduced to 1.1 or less for some time, there may be a “limited buildup of population immunity”.
Significantly, this will reduce the average population’s vulnerability to the virus and slow down its transmission.
Sage said, “If R is 1.1, only 9 percent of the remaining susceptible (i.e. not previously infected) population needs to be infected for R to drop to one, just because of the natural dynamics of the epidemic.
“At that point in time, the epidemic of the population had, in a way, made the epidemic plateau.”
However, they warned that population immunity “is very different from a classic” herd immunity “scenario in which an epidemic has struck a population with limited effects of control measures”.
The experts said that in a population immunity scenario “there will be very little room for easing measures as the absolute level of immunity achieved by the population will likely still be low”.
On October 12, the Prime Minister announced that England would be categorized as “Medium”, “High” and “Very High” (Tiers 1, 2 and 3), which include different restrictions on how to fight the virus.
However, as the number of Covid infections continued to rise, a four-week lockdown was introduced on November 5.
The number of new daily cases across the UK is currently estimated at 55,000 to 81,000.
Experts believe that R is below one in some places, especially in the north west of England.