Covid-19 vaccines are amazing. They have turned what were enormous, horrific epidemics in country after country into manageable problems. Places like the US, UK, Israel, and others, which were until recently speeding headfirst off a cliff, are now celebrating as cases drop and people can finally let go of some of that pandemic anxiety that’s been going around.
As the vaccine rollout continues, however, there are two big important questions remaining: who should our vaccines be going to, and should we vaccinate children against Covid-19? The first question concerns vaccine equity — should rich nations be donating large proportions of their vaccines to poorer countries to assist with the global fight against Covid-19 (answer: yes, obviously).
The second question is related to the first, but is incredibly contentious. While it’s trivially obvious that rich countries should shoulder more of the burden of global health than they do, the question of whether we should vaccinate children — either now or at all — against the coronavirus is hotly debated, especially now that the first ever coronavirus vaccine has been approved for use in children in the United States.
So, let’s look at the pros and cons of immunizing kids, and why it’s probably a good idea for younger people to be getting their shots as well.
Covid-19 Risk For Children
The first side of the coin in this careful balance is the risk to children from the virus itself. We’ve now looked into the death rates from Covid-19 by age in some depth, and we can say for sure that the risk for children is much, much lower than the risk for adults.
That being said, the risk, while low, is definitely not zero. We expect that for every 1 million 12–15 year olds who catch Covid-19, somewhere between 20–30 of them will die. The hospitalization rate is a bit harder to pin down — unlike death, hospitalization varies from place to place — but for some context there have been tens of thousands paediatric hospitalizations for Covid-19 in the United States. This varies a lot by child age as well, with younger children often at a higher risk of hospitalization compared to older adolescents.
So the acute to children risks are relatively low. They are a bit higher than the risks from regular seasonal influenza, a bit lower than the risk of some of the nastier childhood diseases like measles, but they are much lower than the risks that adults face from coronavirus infections.
There are also longer-term risks that we are still working to identify. Fortunately, these also seem to be a bit less common in children than adults, especially as the risks are related to severity of disease. Nevertheless, it seems quite likely that death and acute problems are not the only issues from COVID-19 that children face, which is something we have to take into consideration when we talk about vaccines.
Let’s look at the other side of this coin — vaccinations.
As I’ve said before, Covid-19 vaccines are nothing short of amazing. That we’ve managed to produce safe, effective immunizations against a new global pandemic in such a short space of time is a truly breathtaking feat of scientific success.
That being said, no medical intervention is without risk. Covid-19 vaccines are no different — while there are certainly enormous benefits to not getting coronavirus, the immunization is not totally risk-free.
For adults, we have a very good idea of these risks. We know, for example, that most of the vaccines only very rarely cause serious adverse events, that they often cause uncomfortable and sometimes severe but short-lived problems, and that one or two immunizations are higher risk for some specific issues.
In particular, the highest-risk Covid-19 vaccine out there at the moment appears to be the Astrazeneca jab (which I got in April). There is an identified risk of severe clotting disorders for people who get the Astrazeneca Covid-19 immunization, at a rate of about 1 per 100,000 people. This problem is severe enough that about 1 in 5 of the people who’ve experienced it have died, making the death rate for the vaccine very roughly 1 per 500,000 people immunized.
So at the high end of our risk prediction for adults is a death rate of somewhere around 1 per 500,000 vaccinations — it might be slightly higher or lower, but that’s very roughly what we currently expect to be the worst risk from the vaccines. On the low end, other immunizations like Pfizer and Moderna appear to have much lower rates of life-threatening adverse events and, while it is hard to disentangle the data, they may have risks on the order of 1 event per million or lower.
Part of the reason that this is all so uncertain is that the numbers, while large, are still very hard to unravel. In most cases, people who’ve received Covid-19 vaccines are less likely to die than we would expect, which is probably due to the fact that not all deaths post-vaccine are reported to the system and/or people who are being vaccinated are sometimes healthier than the general population (i.e. healthcare workers)*.
Regardless, we know the issues that Covid-19 vaccines cause in adults very well. So what about children?
Well, it turns out that there are currently studies being run to look at just this question. Pfizer recently concluded the initial analysis of their phase 3 study into their vaccine for children aged 12–15, and found that the vaccine was very effective with no serious side-effect risk. This led the US FDA to agree to an Emergency Use Authorization (EUA) for the Pfizer jab for this age group today.
If you trawl through the EUA papers, you can see exactly what sort of risks the immunization carries. There are some relatively severe side-effects, but they are mostly short-lived and of the sort that we’d expect from a vaccination — some kids got really bad fatigue, there were some quite high fevers, but these represented a very small proportion of those receiving a shot and were over in a day or two. There were no issues of the sort we tend to be most worried about, like serious disease and death, and in general the immunization appears to be as safe and effective for 12–15 year olds as it is for adults. Moreover, there is consistent evidence from this and other vaccines that virtually all side-effects happen soon after vaccination, so the fact that we haven’t found any big ones so far is a very good sign.
Now, this doesn’t mean that all vaccines are immediately safe for all kids. While the EUA process is a bit faster than regular approval, it is still extremely careful and time-consuming, making sure that the vaccines are safe and effective before being given to anyone. The other vaccine manufacturers are running trials as we speak to see if their shots are as good as the Pfizer one for younger people, and we still have very little data on really young children. It’s also possible that further very rare side-effects will be identified in children.
That being said, it’s very good news for older kids, because it appears that there is at least one option when it comes to protecting them from the coronavirus. Which brings us back to the original question: while we now can, should we vaccinate children against Covid-19?
Cost Vs Benefit
The first thing to remember when it comes to the coronavirus pandemic is that, without vaccination, everyone will get the disease eventually at least once. Unless you implement social distancing/mask/etc interventions forever, you’ll eventually see a pattern of endemic disease transmission with the infection getting pretty much every person at least one time.
This means that, when we calculate the cost/benefit, it really is about comparing those Covid-19 risks directly with the risks from the vaccine. Yes, over a 6-month period not every child will get the disease, but if we look at the 10–20 year period unless they’re vaccinated the risk will start to approach 100%.
The calculation is thus fairly simple — on the one hand, the risk of hospitalization/death from Covid-19 itself, on the other the risk from the vaccines. And while the vaccine risks are still relatively unknown, if we look at the Pfizer data we can see that they are also likely to be pretty small. From the FDA documents, the risk of severe events after Pfizer vaccination for 12–15 year olds appears to be no different to that of placebo, at a rate of 0.4% compared to 0.1%. The trial that informed these numbers was too small to capture really rare events, with only 1,000 kids in each group, but it’s still a reassuring figure to see.
It’s also important to think about the greater societal benefit from vaccination. When we immunize kids, we don’t just protect them; we protect everyone around them. If we want to reach and maintain a level of herd immunity — as difficult as that may be — the only real options are vaccinating children or letting them get infected naturally.
Overall, there is little question that children should absolutely be vaccinated against Covid-19. This is, of course, contingent on the vaccines being safe in post-approval monitoring, which will be ongoing for some time, but is nevertheless a reasonable weighting of the risks and benefits.
That being said, it’s also obvious that children in rich countries definitely should not be getting their vaccines right now. We only have so many doses of the immunizations, and the risk of Covid-19 to a 12-year-old in Connecticut is a tiny fraction of the risk that a 70-year-old in Delhi faces, yet the child in America is likely to get their vaccine first. Even once we start to roll COVID-19 shots to kids, there are important questions about who should get their jabs first, with high-risk groups key in any fair prioritisation.
But vaccine equity aside, the fact is that vaccines appear to be substantially lower risk than Covid-19 even for younger people and children. Children should definitely get their Covid-19 shots, it’s more a question of when than if.
*Of course, it is possible that vaccines are life-saving for reasons other than COVID-19, but this is quite unlikely.