The same day retiring National Institute of Allergy and Infectious Disease Director Anthony Fauci urged Americans to get the new Omicron-targeting COVID-19 boosters, a sister agency accidentally pulled the rug out from under him.

The so-called bivalents, composed of the outdated BA.4/5 subvariants and Wuhan strain, have less than 50% absolute vaccine effectiveness (aVE) against symptomatic infection for every vaccinated adult age group compared to the unvaccinated, according to the CDC’s Nov. 22 Morbidity and Mortality Weekly Report. It’s particularly bad for those 65 and up: just 22% aVE.

The figures for relative vaccine effectiveness (rVE), which compares the vaccinated receiving a bivalent booster to not receiving one, show that protection is generally strongest for those who stopped at the primary series — two mRNA doses, no boosters — and who waited the longest between doses.

The data reviewed by the CDC come from the Increasing Community Access to Testing nationwide program, covering about 360,000 nucleic acid amplification tests from nearly 10,000 retail pharmacies from Sept. 14-Nov. 11.

The findings come as COVID has become a pandemic of the vaccinated, with 58% of COVID-attributed deaths in August coming from vaccinated or boosted individuals, according to a Kaiser Family Foundation analysis

“Oh boy,” epidemiologist Tracy Beth Hoeg tweeted about the CDC report, which she said likely overstated effectiveness owing to its “test negative” study design.

“I wonder what to do with these likely very confounded data” — those who get bivalents may be more likely to test — and whether “an actual randomized study would have found any efficacy at all,” said Hoeg, who advises Florida’s Department of Health.

University of California San Francisco epidemiologist Vinay Prasad, a vocal critic of President Biden’s COVID advisers, shared the same skepticism about the design. “If you randomized I bet VE 0-5%,” he tweeted. (The study authors recognized these among other limitations.)

Suspicion that bivalents may provide little if any additional protection compared to the original boosters, as found by two high-profile preprint studies not yet peer-reviewed, was reinforced by Pfizer’s refusal to release full data to date from its human trial of the Omicron booster.

Instead it published a press release on select results from the trial, which started after the feds gave the booster emergency use authorization, while sharing undisclosed trial data with the White House. Moderna followed suit with its own press release.