Most COVID deaths are in vaccines – here’s why that shouldn’t alarm you

More vaccinated people die from COVID than unvaccinated people, according to a recent report from Public Health England (PHE). The report shows that 163 of the 257 people (63.4%) who died within 28 days of testing positive for COVID between February 1 and June 21, had received at least one dose of the vaccine. At first glance, this may sound alarming, but it is exactly as you would expect.

Here’s a simple thought experiment: Imagine everyone is now fully vaccinated with COVID vaccines – which are great but can’t save all lives. Some people infected with COVID will still die. All of these people will be 100% fully immunized. This does not mean that vaccines are not effective in reducing mortality.

The risk of dying from COVID doubles about every seven years more than a patient. The 35-year difference between a 35-year-old man and a 70-year-old man means that the risk of death between the two patients has increased fivefold – equivalently, it has been multiplied by 32. A 70-year-old man no vaccinated could be 32 times more likely to die from COVID than an unvaccinated 35-year-old man. This dramatic change in the risk profile with age means that even great vaccines do not reduce the risk of death for the elderly below the risk for some younger demographic groups.

PHE data suggests that being double vaccinated reduces the risk of being hospitalized with the now dominant delta variant by about 96%. Even assuming that vaccines are no more effective at preventing death than hospitalization (in fact, they are probably more effective at preventing death), this means that the risk of death for people who have been vaccinated twice has been reduced to less than one-twentieth of the value for unvaccinated individuals with the same underlying risk profile.

However, the 20-fold decrease in risk offered by the vaccine is not enough to compensate for the 32-fold increase in the underlying risk of death for a 70-year-old man compared to a 35-year-old man. Given the same risk of infection, we would still expect to see more doubly vaccinated 70-year-olds die from COVID than unvaccinated 35-year-olds. There are caveats to this simple calculation. The risk of infection is not the same for all age groups. Currently, infections are highest in younger people and lowest in older age groups.

Think of it like a rain ball

One way to imagine the risk is like a rain of different sized ball bearings falling from the sky, where the ball bearings are the people who are infected with COVID. For the sake of simplicity, let’s assume that there is a roughly equal number of ball bearings in each age group. In each age category, there is also a variation in the size of the balls. The balls representing the older groups are smaller, which represents a higher risk of death.

Now imagine that there is a sieve that catches a lot of balls. Most people who contract COVID will not die (most bullets get stuck in the sieve). But some of the smaller balls fall through. The older you are, the more likely you are to fall through the holes. The balls that pass through the first sieve are hugely skewed towards the older age groups, represented by the smaller ball bearings. Before the arrival of COVID vaccines, the people who fell through the holes represented the people who died from COVID. The risk was massively skewed in favor of the elderly.

Vaccination provides a second sieve under the first, to prevent people from dying. This time, because we haven’t vaccinated everyone, the holes in the sieve are different sizes. For older people who received both doses, the holes are smaller, so many ball bearings are stuck. Vaccines will save many who would have died before.

For younger people, the holes in the vaccine sieve are currently larger because they are less likely to have received both doses and therefore more likely to pass through the sieve.

If all filtering was done only by the second sieve (without distorting the age-specific risk of death, represented by the first sieve), then we would expect unvaccinated young people to represent a greater proportion of the death. But this is not the case. The first sieve is so skewed towards the elderly that even with vaccination, more of them pass through the second sieve than the younger unvaccinated. Given the UK’s vaccination strategy (vaccinating the elderly and most vulnerable first), you would expect high proportions of people who died from COVID to have been vaccinated. And that’s exactly what we see in the data.

The fact that more vaccinated people die than unvaccinated people in no way compromises the safety or effectiveness of vaccines. In fact, this is exactly what one expects from excellent vaccines, which have already saved tens of thousands of lives.