CDC says vaccine efficacy after 7 weeks is 31%, which CDC spins as not only effective, but hints it provides evidence favoring boosters, too

The study I am about to describe was published in the March 18, 2022 issue of CDC's Morbidity and Mortality Weekly Review (MMWR).  Once upon a time it appeared to be a high quality publication, and also carried useful editorial comments and criticisms of the articles, which have now disappeared.

This study is based on a relatively small group of children collected in parts of 4 states, but surprisingly 76% of the children live in Arizona.  1,052 of the children are aged 5 to 11. They are swabbed weekly for COVID. Half the Omicron infections were asymptomatic. I wonder if CDC distinguished the variants by anthing but timing.

This group is not representative of the entire US, in which a bit over 30% of children in this age group are vaccinated (and by February 14 only 22% in Chicago).  In CDC's group, 65% were fully vaccinated, 7% had had one dose and 29% of the children were unvaccinated.

There were a total of 381 COVID infections in this group:  137 in the fully vaccinated and 184 infections in the unvaccinated.  Which leaves, per my calculation, 60 cases in the singly vaccinated, for whom few data are presented.

Now, there is no way to check CDC's calculations, since each child had a unique number of days in which they were "enrolled," starting 2 weeks after their second dose.

But what CDC states is that the median duration of enrollment in the study for the vaccinated kids is 53 days, and for the unvaccinated kids 41 days.  You would have thought the unvaccinated would have participated for a longer period, since they don't have to wait two weeks until after the second shot to join the ranks of the officially vaccinated. I have no explanation for this.

So how well did the vaccine work during a bit less than 2 months after being considered fully vaccinated?

CDC says that after adjustments, the vaccine was 31% effective at preventing "symptomatic and asymptomatic" COVID in this age group.  At under two months.  Wonder what it is at four or six months? How long till we are in negative efficacy territory?

What are the media going to look at?  The final paragraph, of course, when they are trying to get their story out fast.  In fact, they probably are working off a press release.  What does that final paragraph say?

This study provides evidence that receipt of 2 doses of Pfizer-BioNTech vaccine is effective in preventing both asymptomatic and symptomatic SARS-CoV-2 infection with the Omicron variant among children and adolescents aged 5–15 years. All eligible children and adolescents should remain up to date with recommended COVID-19 vaccinations.

Now we understand why FDA had the manufacturers vaccinate the placebo group at 2 months in all the COVID vaccine trials.  FDA had established a 50% efficacy standard to issue an EUA, and the longer the trials went on, the lower the efficacy would be.  But now FDA and CDC can't even get the 5-11 year old efficacy above 31% in Arizona, and in New York, at 7 weeks efficacy was 12% in this age group. This does not meet the EUA standard.

Here is the NY DOH preprint, fyi

I wonder how they can possibly spin the benefits of vaccination for the 6 month through 5 year olds?   But I expect our federal health authorities will find a way.