In a a NY Times op-ed today (here), a columnist expressed frustration that her child still cannot get a Covid shot, and even hinted that it would be ok to get them one off-label (since the drug is now approved by the FDA, doctors can theoretically prescribe it off-label). This unfortunate advice is bad, and such off-label prescriptions may be harmful to the very children we are trying to protect. We should wait for the data. Here's why.

Let's look at the math. Studies of children aged 6-11 are now underway and appear to be geared to include 3,000 children (see this article). The studied dose will be (at least for Pfizer) one-third the dose those 12 years old and older are given. There are two things that need to be determined from this study:

1) does the vaccine reduce infection?

2) does the vaccine cause serious side effects (hospitalization or death) that can be more frequent than the effects of covid?

To explore these, I'll assume the vaccine is equally effective in young children, with equal side effects, as it is in older children and/or adults.

Regarding infection, with 1,500 children (half the study) taking the medication, and 1,500 not, and given the current rate of circulating virus, we are likely to get a few dozen cases of Covid among them, if not more, relatively quickly. If the vaccine is very effective at preventing infection (it appears to be about 90% effective in 12-15 year old kids, anyway, even for delta), then this will be plenty to prove its effectiveness statistically. In other words, the study appears large enough to rather quickly deduce that the number of infections among vaccinated is less than the number among unvaccinated, and that this difference is not due to chance. This is all assuming the vaccine is equally effective.

Now let's look at the harder problem: side effects (which I will call adverse events hereafter). Adverse events is a term typically used instead of 'side effects,' because in a study we never know if bad things that happen are actual side effects for the drug or just bad things that by happen by chance (might have occurred had the patients not taken the drug). You may have heard that serious adverse events have been quite rare with the Pfizer/Moderna vaccines, and they have been quite rare. However, when it comes to children, serious covid is also exceedingly rare.

Let's first talk about serious Covid. Among children 5-17, over the last 18 months, fewer than 400 died of COVID, which was fewer than died of other respiratory infections (flu/pnemonia without COVID) during the same time period. That's less than 1 in 200,000. As far as hospitalizations, at the peak (in January of this year) the weekly total number of children hospitalized was just above 1 in 100,000 (and it's nearly at that again now). So, over, say, a school year, if our outbreak continues unabated (it won't), we could see roughly a 1 in 2,500 rate (this would be roughly equal to the total hospitalizations in children over the last 18 months combined, so it's very unlikely to be that high). For details see a CDC breakdown here) . In other words, a worst-case scenario might be that 1 in 2,500 school-age children are hospitalized from COVID over the course of the next school year if none were vaccinated.

That sounds bad, but let's now look at the adverse events for the vaccine. For adults taking the vaccine, there was one additional serious adverse event for every thousand vaccinated versus unvaccinated (6 per 1,000 for vaccinated versus 5 per 1,000 for unvaccinated). A serious adverse event is defined as "Serious adverse events were defined as any untoward medical occurrence that resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, or resulted in persistent disability/incapacity." See the CDC site here for details. The adult study was not large enough (only about 8,000 people total) to determine if the small difference of 6 per 1,000 versus 5 per 1,000 could be attributed to the vaccine or was just by chance. When looking at the vaccine for adults, this possibility of a serious adverse event for one in 1,000 would no doubt have been weighed against the clear effect against COVID for adults, which has killed about 1 in 500 US adults and has hospitalized about 1 in 100. The conclusion then, was that even if the 1 in 1,000 rate was real (and not just a statistical anomaly), it was well worth approving the vaccine. BTW, for 12-15 year-olds, the rate of serious adverse events was 0.4% versus 0.2%, or about 1 more for every 500 vaccinations, a larger difference than the difference in adults (see CDC site here).

This same math doesn't work for kids. For kids, we have a possible serious adverse event from vaccination affecting 1 in 1,000 versus hospitalization from COVID for at most 1 in 2,500 (over the course of another school year). To know if the vaccine is effective, we need to have assurances that the adverse event rate due to the vaccine will be less than 1 in 2,500 (this of course assumes serious adverse events are about equivalent to Covid hospitalization). For this, we would need to give the vaccine to a minimum of about 7,500 children (with none suffering from serious adverse events), in order to statistically "prove" the level of serious adverse events from the vaccine is less than Covid hospitalizations.

In conclusion, it's not time to run out and try to get your child an off-label vaccination. The chances of your child getting very sick from Covid, in the meantime, are very small, smaller than they have been in the past of getting sick from flu or pneumonia, and you probably didn't keep your kid in school, or give them unapproved medication for that.