Messing Around With Vaccine Doses Is a Gamble

Every country that is imposing varying degrees of lockdowns because of rising coronavirus infection rates — such as the U.K. did on Monday — is trying to reduce the burden of the disease on its population, health-care systems and economy. The best solution, of course, is vaccines, and three shots have proved in trials to offer protection against disease. That’s assuming they are administered based on data generated from clinical trials. But what happens when the protocols aren’t followed?

The U.K., in its desire to vaccinate as many people as possible as fast as possible, has taken the unprecedented step of implementing a vaccine regimen that hasn’t been tested in rigorous clinical trials and doesn’t have solid efficacy data backing it: It’s stretching the period between the first and second “booster” shot for the two vaccines it has so far approved — developed by AstraZeneca-University of Oxford and Pfizer Inc.-BioNTech SE — to 12 weeks from as few as three. The U.K. is not alone in considering changes to vaccination schedules, with Denmark and Germany also mulling the same. There is also discussion in the U.S. about taking a similar approach or changing dosage levels to allow the current vaccine stockpiles to get to more people faster. These decisions are being made or discussed by highly respected experts who have reason to believe the tweaks may help in the inoculation effort without unduly increasing risks. I am not sure there is sufficient data to back these decisions.