SAGE pushed for FOUR tiers: Scientists warned ministers the local lockdown system must get stronger and called Tier Two ‘barely adequate’ if R is above one, papers reveal
- Papers from sub-group of SAGE say there is a ‘great deal of uncertainty’ on tiers
- They called for a new super-tier, or Tier Four, to be brought in to control Covid-19
- Boris Johnson has unveiled a dialled-up tier system in effort to stop the disease
Government scientists called on ministers to introduce a four-tier system and warned their local lockdown system must get stronger, official documents reveal.
In papers from a sub-group of the Scientific Advisory Group for Emergencies (SAGE) published today, top experts said a ‘more stringent’ approach was needed to stop a third lockdown being ordered across England.
And they said Tier Two – where visiting the homes of friends and family is banned – should be considered the ‘minimum intervention’ to maintain ‘any degree of control’ over the virus.
Ministers were also chastised for failing to consider the speed at which cases surged alongside the total number of infections when enforcing tiers, meaning there was no attempt to slam the brakes onto spiralling cases until the virus was widespread.
Boris Johnson today unveiled his toughened three-tier system, with pubs and restaurants to be forced to go takeaway only under the dialled-up Tier Three.
But there was a silver lining as gyms will now allowed to remain open under the toughest measures.
‘Unlike the previous arrangements, the tiers will now be a uniform set of rules,’ Boris told the Commons via Zoom from his flat above Number 11 where he is self-isolating. ‘We won’t have negotiations on additional measures with each region – it’s a uniform set of rules.’
He revealed that Christmas shopping will also be saved, while there is the potential for small family gatherings over the festive season. Spectator sports will also be able to make a limited comeback in the two lower levels.
Modelling by a sub-group of SAGE revealed areas in Tier One often experienced higher virus growth rates after the system was brought in (blue dots) but those in Tier Two (green and orange) and Tier Three (red) saw lower growth rates
In a statement submitted to ministers on November 11 and released today, the Scientific Pandemic Influenza Group on Modelling, Operational sub-group (SPI-M-O) said there was ‘a great deal of uncertainty’ over the effectiveness of tiers.
‘The implementation of Tier Three restrictions differed across the country with many places having measures beyond the “baseline” Tier Three,’ they said.
‘There are also many confounding factors that cannot be accounted for, including but not limited to: behavioural changes resulting from increases in prevalence irrespective of formal guidance, changing levels of population immunity, changes in local testing strategies and geographical distribution of different measures.’
They said that data suggests Tier Three was cutting the Reproduction rate – the number of people someone infected with the virus passes the disease on to – by a quarter to a half.
Given this, they warned ministers it was ‘likely’ that some localities may need a ‘Tier Four’ top prevent the epidemic from growing. ‘A “Tier Four” that guarantees a reduction in prevalence would be required in most places, if the prevalence is to be reduced,’ they said.
They also criticised ministers for failing to move regions up the tiers fast enough, saying in many cases they waited for the total number of cases to get high instead of leaping on the accelerate once growth rates began to surge.
‘When considering transitions from national measures to a localised tiered approach or between tiers, both prevalence and growth rate of the virus need to be considered,’ they said.
Boris Johnson today announced a dialled-up tier system
‘Basing transitions on prevalence alone leads to a perverse outcome where growth rates four of seven are highest in the lower prevalence areas and interventions sufficient to halt this growth do not take place until prevalence is very high. This has led to high prevalence across the whole country and, ultimately a second national intervention.’
In papers released by SAGE today from a meeting on November 12, shortly after the second lockdown in England was imposed, they said the data suggests Tier Two is the ‘minimum intervention’ needed to maintain any degree of control on transmission.
But they added: ‘Though this would not be the case in all places and there is significant uncertainty.’
‘In most cases moving from Tier One to Tier Two would slow growth rather than reverse it,’ they said warning that tighter measures were likely to be necessary.