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Vaccines Reduce Risk: A Look at the Changing Age-Related Mortality Risk of COVID
Also, RIP, Colin Powell
This morning, I woke to the news that Colin Powell died of COVID:
Colin Powell, the first black U.S. Secretary of State and Chairman of the Joint Chiefs of Staff, died Monday at the age of 84 from complications of COVID-19, according to a post from his official Facebook page.
Powell was fully vaccinated.
Various people will be glomming onto this story to hawk whatever point-of-view they have on vaccines: see, the vaccines are useless; see, if only the unvaccinated would get vaccinated this wouldn’t happen.
I do have a point of view, but it is reflected in neither of the above major perspectives sure to be yelled all over the partisan channels today.
I will be using CDC statistics as well as the example of Colin Powell to emphasize the following points.
Covid vaccines reduce relative risk for individuals (and by a large factor)
Baseline risk has a huge difference by age
Baseline risk varies over time (and we’re not sure why, as it doesn’t fit the standard models well)
Risk reduction doesn’t mean reducing to zero
But first, a video I made some weeks ago.
Video break: Age profile of total deaths in the U.S.
Excess mortality for people age 25-44 has not come in wave patterns like the elderly.
The rest of this post will focus solely on COVID deaths, however.
The age structure of COVID deaths has changed
In my last post, I looked at the 4 waves of COVID deaths we’ve seen in the U.S., through September.
Now, let’s look at how those deaths broke out by age.
Ummmm, pretty colors, eh?
Okay, it’s difficult to see how the age structure of the deaths is changing, as the total number of deaths has been doing these “waves”. Squinting, one can see the number of age 85+ deaths came down a lot between the January 2021 peak and the summer 2021 peak… but it seems that age 50-64 had even more deaths! It’s difficult to eyeball it, though.
So let us change to a stacked 100% column graph — this gives the percentage of deaths by each age group for each week. Even when deaths go down, there are non-zero amounts, and we can see what the age distribution of deaths was for each month.
A little better, as we can see a few trends:
The share of deaths in the oldest age group is going down, notably starting in January 2021.
The share of deaths in the age group 50-64 grew a lot.
The share of deaths for the age groups spanning 30 – 49 grew a little.
Finally, let’s look at a line graph of those percentage shares of deaths:
Now we’re cooking with gas. Look at that black line, of COVID deaths for those age 85+. They used to have the highest share, peaking at 35% of official COVID deaths in the U.S. in May 2020. But after their December 2020 peak, their share has dropped down to 15% of COVID deaths.
In the meantime, the age 50-64 group increased their share of COVID deaths from 13% of total December 2020 U.S. COVID deaths up to 28% of COVID deaths in September 2021.
Now, the percentage of COVID deaths incorporates two factors: the size of the population of that age group (and of course, the Boomers straddle the 50-64 and 64-74 age groups) and the death rate for each age group. If we really want to dig into the trajectories of COVID mortality impacts on these groups, we need to dig into the death rates.
Changing death rates by age group
To get at estimated death rates, I am using the estimated 2020 U.S. population for specific age groups in doing COVID deaths per 100,000 population. The population estimates came from here: 2019 ACS 1-year age and sex breakout, using that age distribution and trueing up using the 2020 Apportionment Count.
I am most interested in gross trends and not multiple decimal points in the rates, so I did no further adjustments to the base population estimates, but held them constant for the entire period March 2020 – September 2021.
Here are the straight rate results:
So while age 50-64 has the highest percentage of COVID deaths currently (that is, from current COVID deaths, the age group most represented is age 50-64), the actual death rate for each group is strictly ordered by age, even after vaccinations.
Changing relative mortality risks
But let us make it clearer, to erase some of the effects of the “waves” by doing a ratio of each death rate against the comparison group of age 50-64.
And there we go: we can see the relative risk for those age 85+ dropped from over 25 times the “base rate” of those age 50-64, down to 5. That’s an 80% reduction.
My assumption is that vaccines drove that, given that the oldest people were given access to vaccines first, when they became more widely available in December 2020. That was too late to dampen the winter 2020-2021 wave of deaths, but it sure helped keep it down in the summer wave.
Here’s a graph of vaccination rates, using this data source:
There is a little of an anomaly for vaccination rates here, but it does make sense to me, as many very old people can be very disabled and dependent on others to make sure they get vaccinated… and some may have health conditions such that they can’t get vaccinations. The only “near-elderly”, that is age 65-74, tend to be mobile still and have fewer impairments.
But we can see that, in general, the oldest got vaccinated first, and that younger people have been slower to get vaccinated. Some of this is due to younger people getting access later. There are a variety of reasons that people aren’t getting vaccinated and I’m not going into it.
Given the high level of risk the elderly have, it’s good they’re taking up vaccines in such high numbers.
Alternative theories to drop in relative risk
I have heard others posit that the “vulnerable” had already been cleared out by earlier waves of COVID, and thus only the hardy people remain.
I will put a few facts in front of you, and you think it through:
- The population age 85+ in the U.S. in 2020 was 6.3 million
- Through July 2021, there were a little over 180K COVID deaths for that group
- That’s about 3% of the age 85+ population
Do you think only 3% of the age 85+ population is vulnerable to COVID?
Pretty much all of them are “vulnerable”. The mortality rate for people age 85 (much less older) was 7.3% for females and 9.5% for males in the most recently available tables. It only goes up from there.
There is a huge difference in mortality by age for just non-pandemic years, and it’s also true for COVID.
There may be a few hardy souls with a base risk similar to the middle-aged without vaccines, but the percentage is not high.
The vaccines have been having an effect in cutting risk.
RIP, Colin Powell — Reducing Risk Does Not Mean It’s Zero
So, while various people will be trying to “score points” off of Colin Powell’s death, here are some very key facts about his health condition:
- He was 84 years old
- He had multiple myeloma
Powell had multiple myeloma, a cancer of a type of white blood cell, which can harm the body’s immune system. It’s unclear what complications he experienced from Covid-19 or when he tested positive for the disease. The family also did not say when he was vaccinated or if he had received a booster shot.
His death, and the death of other vaccinated people, don’t necessarily “prove” the ineffectiveness of vaccines. You have to consider their base risk to begin with, and given his age and health status, Powell had a very high base risk level.
You can cut a risk level by 80%, but it can still be substantial after risk reduction. It does not mean what you did to reduce risk was ineffective.
We have been used to risk interventions of similar magnitudes, for what it’s worth (and some of less effectiveness). Flu shots have a range of effectiveness, depending on the specific strains of flu in circulation, for example. Seat belts and airbags have cut car crash fatalities by a lot… but people still die in crashes while using these risk reduction interventions.
So yes, the vaccines have been effective in cutting COVID mortality risk, and no, the vaccines don’t take the risk to zero.
And RIP, Colin Powell.