Science, Statistics and Studies [SARS-CoV-2]

Imperial College modelling underpinning the unlocking scenario outlined by the PM today

https://assets.publishing.service.gov.uk­/government/uploads/system/uploads/attac­hment_data/file/963440/S1129__Unlocking_­_Roadmap_Scenarios_for_England_.pdf

Figure 2E shows a full unlocking at the end of April (as favoured by the hard-line Covid Research Group) would potentially lead to a 4th wave as big or bigger that we've just been through which is simply unthinkable. Even with the most gradual unlocking scenario another 40,000 to 60,000 deaths are modelled to occur by the end of the year.

I can’t seem to find this in the report, so apologies if I missed it, but do these projections all presuppose that there will be no return to lockdown? So, we would get another wave, but without taking any particular measures to reduce it?

That's right - the modelling makes no assumptions about returns to lockdown. They model 5 scenarios of release from lockdown where the main difference between each scenario is the rate of relaxation of different aspects of the lockdown. Abrupt ending of all current restrictions at the end of April is predicted to produce another wave. Even the slowest easing ending in early August is modelled to lead to a small wave next autumn

So, if we’re getting vaccinated at (roughly) 90% uptake amongst the most at risk, and the rest of the adult population is going to be offered the vaccine over the next few weeks, would the majority of these future deaths be among older people who have declined to be vaccinated? Or does the vaccine provide less protection against severe illness than we have, perhaps, allowed ourselves to believe?

Nice blog here on the data behind the vaccines and lockdown: https://makingsenseofcovid19withs.com/bl­og/

The modelling makes assumptions about vaccine efficacy against severe disease, disease, and infection for both the AZ & PF vaccines, vaccine uptake rates, and reduction in lockdown measures. As they say "Our results are highly dependent on the assumed (optimistic) vaccine efficacy, uptake, and rollout speed".

There isn't a breakdown of where deaths will occur in terms of the split between those vaccinated and those unvaccinated, or in terms of age profiles. My guess would be that future deaths will still broadly follow the age distribution we've seen up until now, but as you say with additional deaths associated with cohorts who don't get vaccinated for whatever reason and particularly older members of those groups.

The study doesn't suggest that the vaccines are any less effective than has already been shown. It just demonstrates how even slightly imperfect vaccine efficacy has an effect on serious illness across a large population.

and the rest of the adult population is going to be offered the vaccine over the next few weeks

Five months before the vaccine is available to all adults. There’s potentially a big slowdown in new people being vaccinated at the end of this month as supply will be spoken for by the massive backlog of second doses.

(There are rumours of a large increase in supply which could balance things out. We’ll see)

Number of daily cases continuing to drop, according to the Google reporting. Now around 3000 cases per day according to the 7 day average. I think the key thing I noticed is the although the deaths are down, the death rate is far lower. Previously it was around 2%, now it appears to be around 0.6%. Without looking into it, this probably means there are fewer hospital admissions (as a percentage of the number of cases) and fewer cases with serious side effects. To me this seems like good news.