A recent analysis in Sweden looked at overall hospitalization rates in kids by whether they had a single dose of COVID injections (“ever-dosed”) or not (“never-dosed). But they did not compare the hospitalization of those fully-dosed to those never-dosed.
This is important because about 15% of kids who got jab #1 did not come back to complete the regimen to get jab #2. But what if those who never came back had experienced negative effects just short of hospitalization?
Thought Experiment
If those who never came back for Jab #2 — possibly because of bad reactions to Jab #1 — had, instead, went forward to get Jab #2 anyway, then what rate of hospitalization would they get?
Using data from mRNA trials on serious “adverse events of special interest” (serious AESI), you can estimate the hospitalization rate if all of the kids who got Jab #1 had went back to get Jab #2.
That’s because a serious adverse event is one that requires hospitalization. Here is a chart showing the expected effect from 10,000 kids getting fully-dosed with mRNA shots:
[click to enlarge]
The blue bar at left indicates that 1.2 COVID hospitalizations is expected to be prevented by the 10,000 kids getting fully-dosed (as found in Sweden). The orange bar at right indicates that 12.5 hospitalizations due to serious AESIs is also expected in those same 10,000 kids getting fully-dosed.
That’s over 10 kids “put into” the hospital for every one of them who was “kept out of” the hospital.
Note: Regarding the orange column, the error bars on the 95% confidence interval (taken from the study cited below) suggest that, at minimum, there will be 2.1 kids hospitalized due to serious AESI for every 1.2 COVID hospitalizations which are prevented — indicating that the “net harm” is statistically-significant.
Here is the same graph with notes in it:
[click to enlarge]
And here is a graph showing that, by the end of 2021, the share of kids in Sweden getting Jab #1 had flattened out, so that not much more kids would ever get Jab #1 after that:
And the same thing is true for Jab #2 in kids in Sweden — by the end of 2021, the share of them getting Jab #2 had pretty much flattened out:
Because they both flattened out to a rough “steady-state”, you can compare the raw shares to each other — discovering how many kids who got Jab #1 never went back to get Jab #2. Here are the same two graphs but this time showing the share of 15-17 year-olds for each dose level, starting with Dose #1:
That’s 76.3% who got Dose #1. Now let’s look at the share who got Dose #2:
Less than 65% (64.16%) came back in order to get Dose #2, at least by the cutoff date of 31 Dec 2021.
Though there is a small amount of “catch-up” in this share who got Dose #2, for the time-frame of the Sweden study, the share of single-jabbed kids was always at least 15% higher than the share of double-jabbed ones.
This indicates the possibility that many kids got bad reactions and did not go back for Jab #2.
Application to the Sweden Study
This would then give rise to an artificially-low child hospitalization rate in the Sweden study (which only compared Dose #1 to the never-dosed kids). It would be showing up as low because of the idiosyncracy of overlooking that subgroup of kids who were fully-dosed when comparing the relative hospitalization rates to the never-dosed.
By keeping the entire cohort of “ever-dosed” together, it watered-down the hospitalization rate of those “double-dosed” — who would remain offset by those “single-dosed.”
For efficacy, the authors specifically studied the “double-dosed” group — but for safety, they aggregated the hospitalization rates for all who had ever gotten a single dose or more.
Reference
[over 8,000 fully-dosed kids are required to prevent a single COVID hospitalization] — Nordström P, Ballin M, Nordström A. Safety and effectiveness of monovalent COVID-19 mRNA vaccination and risk factors for hospitalisation caused by the omicron variant in 0.8 million adolescents: A nationwide cohort study in Sweden. PLoS Med. 2023 Feb 21;20(2):e1004127. doi: 10.1371/journal.pmed.1004127. PMID: 36802397; PMCID: PMC9990916. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9990916/
[the additional hospitalizations for Adverse Events of Special Interest for each 10,000 fully-dosed people aged 16 and up is +12.5 per 10,000 fully-dosed] — Fraiman J, Erviti J, Jones M, Greenland S, Whelan P, Kaplan RM, Doshi P. Serious adverse events of special interest following mRNA COVID-19 vaccination in randomized trials in adults. Vaccine. 2022 Sep 22;40(40):5798-5805. doi: 10.1016/j.vaccine.2022.08.036. Epub 2022 Aug 31. PMID: 36055877; PMCID: PMC9428332. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9428332/