The rotavirus experience taught the CDC a hard-earned lesson: Speaking in absolutes about vaccine safety and efficacy regardless of trial standards can backfire. In nearly every dimension by which trial data are measured—proper endpoints, size, rigorous randomization, and other factors—the RotaShield trial was far more robust than the Pfizer and Moderna infant and toddler COVID vaccine trials. Furthermore, if the identification of safety signals is not quickly acknowledged, it becomes even harder to recover trust. More and more Americans are wondering, for example, why Canada and several European countries have advised against the Moderna vaccine for people under 30 due to myocarditis risks, while the U.S. government still won’t even acknowledge the higher risk of myocarditis.

Clinical trial data expert and Tablet contributor Dr. Vinay Prasad has pointed out many times that “expedited pathways do not always benefit people, but they always benefit companies.” This might help explain why no other country in the world has started vaccinating infants against COVID, and only a handful have vaccinated toddlers. (In addition to the United States, the only countries vaccinating 2- to 3-year-olds against COVID right now are Cuba, China, Argentina, Bahrain, Venezuela, Colombia, Hong Kong, and Chile, none of which are using mRNA vaccines.) It is perhaps especially damning that no other country collaborated with the United States on the mRNA COVID-19 vaccine trials for infants and toddlers, which could have quickly enabled enough trial participation to study effects of the vaccines against severe disease, as was done in the RotaTeq trial. Tellingly, the Danish minister of health recently claimed that it was a “mistake” to vaccinate children under 16 against COVID at all, saying, “we’ve gotten smarter and would not recommend the same today.”

In June, the CDC had the chance to help rebuild public trust: In the absence of trials and data that would have met the gold standard for scientific rigor, the CDC could have made a softer recommendation based on the data it does have. It could have been honest about the trials’ shortcomings and what these data do and do not show. It could have told the public that the data are preliminary, do not establish efficacy against severe disease or long COVID, and do not rule out the possibility of a rare adverse event. Perhaps it could have recommended COVID vaccines for high-risk children, and remained cautious about the benefits for healthy children who have already had COVID infections. The CDC and FDA together could have insisted that blanket approval and recommendations would only come after a properly conducted vaccination trial—one that would give pediatricians and public health officials the confidence to make the evidence-based recommendations parents are seeking.