Vaccine Makers to Study Rare Post-Vax Syndrome, Spike Persistence After COVID Shot

MedPage Today September 4, 2025
Judy George

Trials also will evaluate whether vaccination reduces long COVID symptoms

In an unusual move, the FDA asked vaccine makers to conduct randomized studies evaluating possible long-term effects of the COVID-19 shot, including spike persistence and post-vaccination syndrome symptoms.

In the approval letter for the latest version of the Pfizer (Comirnaty) COVID-19 vaccine, the FDA requested an exploratory, placebo-controlled study to assess whether circulating SARS-COV-2 spike antigen persisted and whether self-reported symptoms of post-COVID-19 vaccination syndrome or long COVID emerged at months 1, 3, 6, and 12 in vaccine and control arms.

In decisional memos for the updated Moderna (Spikevax, mNexspike) and Novavax (Nuvaxovid) shots, the FDA’s Center for Biologics Evaluation and Research (CBER) Director Vinay Prasad, MD, MPH, outlined why...

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