Has there been any effect of the rollout of SARS-CoV2 vaccinations on excess deaths in Scotland?
One simple way of showing a relationship between two datasets is to graph one against the other. This is made more complex with a changing situation like monitoring the rollout of a vaccine. The vaccine programme has ensured that around 95% of Scotland’s most elderly population has now had their first dose of either the Pfizer or AstraZeneca vaccines. I’ve linked these together in this way:
- Calculate the number of excess deaths per week recorded in 2020 and 2021 for each age group
- Read the cumulative percentage of the population that has been vaccinated in each age group since vaccinations began in December 2020
- Graph excess deaths versus versus cumulative percentage vaccinated
- Label each weekly datapoint with the date.
This way I create a graph that shows the relationship between time, excess deaths and the percentage of each age group vaccinated.
Our hope is that over time the number of excess deaths (which is expected to be caused mainly by COVID-19) should reduce as the percentage of the population vaccinated increases.
So I start with calculating excess deaths. This uses the average deaths over the previous 5 years (2015-2019) and is defined as Excess Deaths = Deaths in 2020 and 2021 minus Average Deaths for 2015-2019. I’ve calculated excess deaths for each week and for every age group available. The 2015-2019 and 2020-2021 deaths are available from the National Records of Scotland. I calculated the whole country deaths by summing the deaths for every health board for each of the age groups.
Here are death data for 2015-2019.
When averaged, they look like this:
Deaths for 2020-2021 look like this:
Then, excess deaths for 2020-2021 look like this:
The cumulative vaccination data are graphed next. This data is available from NHS OpenData.
One thing to note is that the age groups for vaccinations and excess deaths are different. Thankfully, they generally overlap nicely except for 16-29 (vaccinations) and 15 to 19, 20 to 24 and 25 to 29 (excess deaths). However, this has little effect on the general picture as very few 15 year olds die each week.
Finally, now that I have excess deaths and cumulative percentage of each age group vaccinated, I can then graph them together. I’ve concentrated on Dose 1 of each vaccine as the majority of those vaccinated have only received that dose.
My observations are:
- Vaccination is associated with an increase in excess deaths from mid/end January until end February for the oldest three age groups (45, 151 and 113 weekly excess deaths for 18/01, 25/01 and 01/02 respectively for the 80+ age group – which increased from -19 excess deaths on 11/01)
- There are more moderate but maintained excess deaths in 55-59, 60-64 and 65-69 between 25/01 and 15/02 (but it’s hard to say anything for 55-59 and 60-64 because less than 50% of those age groups has been vaccinated so far)
- There are no observable effects in the youngest age groups (but these have less than 12% vaccinated)
This analysis doesn’t prove a causal link between vaccination and excess death. After all, I don’t have access to data which shows the number of those who died each week who had been vaccinated. There are several other factors that may also have led to excess deaths over that period – the ongoing lockdown and COVID being the two most obvious factors. However, the rate of COVID deaths has also decreased over that period, and no one yet knows the full effects of lockdown on excess deaths.
The main point is that in the age groups that have received the majority of vaccinations, the weekly number of excess deaths has been maintained (and increased in some age groups) throughout the first dose vaccination programme, and is only reducing now that it has largely ended.
If there is a causal link between vaccines and excess deaths, is the number of deaths associated with the vaccination programme an acceptable cost for reducing the risk of SaRS-CoV2 transmission for the rest of the population?