The big news in the last week was that the authorities in Scotland have decided that enough is enough; they’re going to stop publishing data on infections, hospitalisations and deaths by vaccine status. This isn’t surprising – the best way to stop people knowing that your public health interventions have failed is to stop giving them the information that will inform them that they have failed. Without these data the Scottish authorities can keep on saying that the vaccines are magnificent and have saved the nation, whereas the data suggest that even if they had some short term positive impact, they at best ‘paint a complex picture’.
At least in England there is still fairly good data being published on the performance of the vaccines, for now…
We’re clearly in a situation where the Covid vaccinations haven’t solved the Covid epidemic, and might even have made things worse (deaths). It certainly isn’t the case that this is a pandemic of the unvaccinated, when 72% of hospitalisations and 87% of deaths are in the vaccinated. Of course, the devil is in the detail, and in this specific case the variation between different age groups (older people are more likely to be vaccinated but also more likely to die). This week’s data indicate that infections continue to tumble for all age groups and vaccination status – the December and January Omicron wave appears to be receding fast. The data continue to show that for nearly all age groups the more vaccine doses you have the higher your risk of infection with Covid.
Two age groups stand out as different from the others – those aged under 18 and over 80. For those aged under 18 it is likely that the higher infection rate in the unvaccinated at least partially reflects their more recent vaccination (for all doses). It isn’t clear what is going on for those aged over 80 (and, to a certain extent, those aged 70-80). It is always worth remembering that the immune system of those under the age of about 12 and over the age of about 65 isn’t the same as for the majority of adults and you might expect to see different disease patterns and characteristics in these groups.
From the infection rate data we can again estimate the vaccine effectiveness against infection – negative for all age groups other than those aged under 18, and significantly so for those having taken a booster dose.
For this week we’ve got enough data to present graphs of vaccine effectiveness against time (this year) for all age ranges – as this is now rather a lot of data to present in one go I’ve split it into a graph for those aged under 50 and another for those aged over 50. First the changes with time for those aged under 50:
One dose of vaccine appears now to offer a relatively low but stable increase in the risk of infection, two doses offer a stable but higher risk of infection, while the risk of infection appears still to be increasing for those that have had a booster dose – those in their 40s being up to three times more likely to be infected than the unvaccinated. The silver lining in these data is that the impact of the vaccines in terms of increasing infection on those aged under 18 appears to be low; I hope that this reflects their robust innate immune system and isn’t simply because their recent vaccination means that there hasn’t been time for the increased risks to emerge.
The infections data for those aged over 50 paints a different picture. The only clear indication is that all age groups for any number of vaccinations have an increased risk of Covid, compared with the unvaccinated.
It is still unclear why the vaccine is resulting in increased risks of infection. There are several mechanisms that might explain it and really there should be much more research being done on this because they’ll determine the likely longer term outcomes of the vaccination programme.
The complication with the infections data is that there are concerns about reduced testing levels (including the likely-immient removal of free tests) and with the impact of reinfections. While reinfections are now included in the total, they’re only classed as reinfections if 90 days have passed since the previous test; whether 90 days is appropriate remains open to question.
The situation with testing is illustrated by the difference between official case number for the past month with people reporting symptomatic Covid to the Zoe symptom tracter – I’ve included graphs for both below; official data top, Zoe data middle. I’ve also included the latest ONS Infection Survey graph for England (bottom).
Note how official case numbers have dropped since the Christmas Omicron peak, while the Zoe Symptom Tracker is showing a second peak in the data. The ONS Infection Survey shows a pattern part way between the two. The impact of this complication on our analysis is unclear. It is of note that genomic analysis of a sample of test swabs suggests that the second peak in the Zoe data isn’t simply the BA.2 variant – that doesn’t seem to have infected large numbers in the UK (yet).
On the topic of variants, we’re now beyond the point where the arrival of Omicron variant would still be causing vaccine effectiveness to drop in our analysis – if it were simply an effect of Omicron having achieved more vaccine escape then the vaccine effectiveness should have flatlined over the past two or three data points, however the data suggest that more is going on – but is it continued and rapid antibody waning or something else? Consider the the data on variants published by the UKHSA:
The period covered by the latest report is highlighted in the red rectangle to the right of the graph. The continued decline in vaccine protection suggests that it is possible that variant Omicron BA.1.1 (and/or perhaps BA.2) has achieved further vaccine escape, compared with variant Omicron BA.1, and these variants might even be causing rapid reinfections in the short term. Again, more information is required to explain the disparity between the official and Zoe data.
Regarding vaccine protection against hospitalisation, the data are fairly consistent – three doses of vaccine still offer some protection against hospitalisation for all age groups, two doses appear to offer approximately zero benefit, while those having had only a single dose appear to have an increased risk of hospitalisation.
Note that unlike the infections data, the data for hospitalisations is rather robust, albeit complicated by the question of ‘with vs of’ Covid.
The data for protection against death is similar to the hospitalisations data; a fair amount of vaccine protection remains for those who have received a booster dose, two doses appear to give negligible protection and a single dose appears to offer negative protection (i.e., increases the risk of death). Note that I only included data for 40-80 year olds in this graph; the death rate in those aged under 40 is very low and gives ‘noisy’ results, while the data for those aged 80 or over is complicated by the very large range in vulnerability within the group.
It is important to note that although this last graph shows those with only one or two doses of vaccine to have an increased risk of death, the advent of Omicron has reduced the mortality rate of Covid significantly. The widespread ‘fear of Covid’ that is affecting so many lives is based on the information we had about the risk of the virus in early 2020; this level of fear isn’t appropriate in early 2022.
Amanuensis is an ex-academic and senior Government scientist. He blogs at Bartram’s Folly.