It has been estimated that the Covid vaccine programme prevented over a quarter of a million hospital admissions and more than 120,000 deaths in the UK up to September 2021, according to BBC Health Correspondent Fergus Walsh states
His statement follows an article this week highlighting side-effects resulting from the AstraZeneca Covid vaccine.
These figures come from a UKHSA Vaccine Surveillance report which was published on September 30th 2021.
The Daily Sceptic reports: As it happens, the UKHSA estimates were actually for England rather than the U.K. and the precise numbers were 261,500 hospitalisations averted in those aged 45 and over by September 19th 2021 and 127,500 deaths averted by September 24th 2021.
The estimates were calculated by applying vaccine effectiveness rates available at the time to known vaccination, hospitalisation and mortality data. With such models, the first question to ask is whether the results pass a basic plausibility test. Let’s see.
In the first nine months of 2021, the ONS reports about 60,000 Covid-related deaths in total. If we believe vaccination prevented 127,500 deaths, then without vaccination there would have been nearly 190,000 deaths in that period.
In the first nine months of the pandemic before vaccination (i.e., March to November 2020), the ONS also reports about 60,000 Covid-related deaths. In other words, if vaccination prevented 127,500 deaths, then without vaccination the claim is that we would have seen three times as many deaths in the nine months post-vaccination as in the nine months pre-vaccination. Given that vaccination was rolled out during a period when Covid deaths were already decreasing following the huge infection wave at the end of 2020, that is more than a stretch – it is simply implausible
Consider further that we know that a large proportion of deaths in 2021 were actually in the vaccinated (the Vaccine Surveillance Report mentioned above reveals that in September 2021, for instance, only 21% of Covid-deaths were amongst the unvaccinated) and many more occurred early in the year before people had access to vaccination. That makes the potential pool of people whose lives might have been saved by the vaccine even smaller and the estimate of 127,000 deaths averted even less credible.
The problem with the UKHSA estimates is fairly obvious. The vaccine effectiveness rates they use relate to hospitalisation or death rates for the vaccinated relative to rates for those unvaccinated and not previously infected. For this and other reasons they dramatically overestimate the effect in real world populations in which significant proportions of people have immunity from a previous infection and in which (as we now know) vaccine effectiveness wanes rapidly over time.
There is another way to test the plausibility of the estimates quoted by the BBC. In January 2023, the UKHSA produced estimates of the expected number needed to vaccination (NNV) to prevent a hospitalisation or death. These were also modelled estimates, but in contrast to the earlier approach, they used updated vaccination effectiveness rates and, crucially, took account of the fact that effectiveness waned over time.
