Pfizer Vaccine Effectiveness In Kids 5-11 Drops To 12% After 28 Days | New York Study Analyzed
There’s new data out from the New York State Department of Public Health showing that Pfizer vaccine effectiveness against Omicron dropped down to 12% in Kids 5-11 shortly after they completed their primary series (dose 1+2). So, in this publication, the salient information from this new paper will be broken down into easy to digest terms. Moreover, supplementary materials like graphs and charts will be explored to make this a little bit easier to understand. Finally, after everything has been laid out, i’ll explain what all this mean for public health policy.
The Data
Below, in pictures and text the data will be explained. Of course, please revert to the source linked in the first sentence of this publication. That said, as a prelude to the information farther down, please understand that researchers in this paper took data from 3 NYS databases to compare outcomes for vaccinated kids 5-11, and 12-17 vs an identical unvaccinated cohort.
n=365,502 children 5-11 dose 1+2
n=852,384 children 12-17 dose 1+2
Matched with nearly identical unvaccinated cohort
5-11 received 2 10 mcg doses of Pfizer mRNA
12-17 received 2 30 mcg doses of Pfizer mRNA
Timeframe: November 30th 2021- January 30th 2022 (predominantly Omicron)
Study aimed to observe vaccine effectiveness against COVID infection and hospitalization in age groups 5-11 & 12-17 who received COVID mRNA vaccination from Pfizer. It is important to note that median time past since vaccination in the 5-11 old cohort was 51 days. Conversely, in the 12-17 year old cohort, median time past since vaccination was 211 days. That means some kids in this paper were analyzed after a median of 51 or 211 days post vaccination
Positive tests were measured with laboratory confirmed NAAT testing
Vaccine effectiveness for kids 5-11 years olds declined from 65% to 12% at day 28, and then from 12% to -41% at day 42 (FIG. 2 📸)
Comparatively, in kids 12-17 vaccine effectiveness declined from 76% to 56% at day 28, and then from 56% to 46% at day 42 (FIG. 2 📸)
In (FIG. 1 📸), the solid top brown line indicates vaccine effectiveness against infection for age group 12. On the other hand, you can see a dramatic change in vaccine effectiveness between the two groups (11;12) at age 12 (brown solid line) VS age 11 (blue dotted line). Such a substantial difference could be attributable to the non-similar dosage of vaccine administered. For instance, 12 year olds received 2 30 mcg doses of Pfizer, while 11 year olds received 2 10 mcg doses. In other words, a difference in strength could account for plummeting vaccine effectiveness between those aged 11 & 12
In those aged 5-11, protection from hospitalization was reduced by nearly 50% after a month and a half. Problem. Confidence interval was very wide (from DECEMBER -189, 100% TO JANUARY -12, 75%) so these results are something to ponder at best (FIG. 3 📸). To drive that point home, the confidence interval being so large means vaccination likely didn’t protect from severe disease or hospitalization in this cohort because the study was too underpowered. That is to say, children experience less hospitalization compared to other age groups. So you’d need substantially larger numbers to draw any conclusions about hospitalization
All and all, considering the results from this study, authors suggested a layered approach for kids like adjusting vaccine dose in those 5-11, masking, etc.
FIG. 3 📸
Confounders/ Problems With The Data
There are many problem with the data. However, even correction of confounders would still leave vaccine effectiveness in the gutter for each cohort. Problematic variables will be listed in numbered points below:
TESTING: Home testing was increased during this period and not accounted for in the data. That means certain groups of people who had more access to home/lateral flow COVID testing at the first sign of a sniffle would likely have their child tested, where others without tests would not have thus resulting in an uneven distribution of positive test results between vaccinated and unvaccinated kids. In other words, this study didn’t control for home testing. Finally, vaccinated individuals would likely be tested more than those unvaccinated which translates to more positive results
DOSE DIFFERENCES: Vaccine strength was different between two cohorts which likely led to lower effectiveness in children aged 5-11. Specifically, those 5-11 received 2 10 mcg doses, while those 12-1 7 received 2 30 mcg doses. As you could imagine, difference in doses would generate varying effects
DIFFERING TIME OF VACCINATION: The paper compared early vaccinators (kids aged 5-11), with later vaccinators (aged 12-17) who’s immunity could have been weaker from declining vaccine efficacy
COMORBIDITIES: This study doesn’t control for comorbidities which would leave an individual at higher risk for infection
The Take Away
The overall trend from this study revealed that vaccine effectiveness for kids 5-11 was substantially diminished. Specifically, from 65% down to 12% against infection in a matter of a month. Even worse, effectiveness against hospitalization reduced by nearly 50% in 1 month or so.
Now, let’s say certain variables were adjusted which brought vaccine effectiveness down from 65% to 45% instead of 12%. Still, 45% wouldn’t have earned EUA approval from FDA. It should be stated that efficacy during initial EUA approval of these vaccines had to be at least 60% or else back to the drawing board. Also, such low vaccine effectiveness exhibited in this paper would not prevent transmission, or change the trajectory of pandemic transmission in any cohort by age, sex, etc.
All and all, this paper was interesting and revealed a trend like many other recent papers did. That being, vaccine effectiveness against omicron seems to be dwindling. Be that as it may, would you vaccinate with a product only 12% effective?
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