A randomized, double-blind, placebo-controlled clinical trial tested a four-day oral supplement, “FoTv,” which is made from the mycelium — the root-like network — of two types of mushrooms: Fomitopsis officinalis and Trametes versicolor (FoTv).

Participants began taking the supplement on the same day they received their vaccine and the authors reported that the supplement acted as a natural immune regulator and decreased vaccine side effects while preserving or increasing antibody levels and helping vaccine protection last longer. They say it could replace synthetic immune adjuncts which help the body produce a stronger antibody response - but have been linked to side effects such as fever, chills, fatigue and muscle aches.


Credit: UC San Diego

This was a small trial, 90 adults receiving a COVID-19 vaccine who were randomly assigned to take either FoTv or placebo capsules by mouth for four days, starting on the day of vaccination. Safety, short-term vaccine side effects and antibody levels were gathered at intervals up to six months. The strongest results were seen in participants who never had COVID-19 and had not been vaccinated before joining the study. Those who took FoTv reported significantly fewer side effects after vaccination compared with those taking the placebo.

No adverse events were reported and if the work holds up under larger trials, it could be affordable, since fungal mycelium can be grown using standardized, scalable and medical-grade production methods.

“Antibody levels usually rise, peak about one month after vaccination, and then slowly decrease,”said principal investigator Dr. Gordon Saxe, MD, PhD, MPH, professor in the Department of Family Medicine at UC San Diego School of Medicine. “In this group, we saw a significant decrease in vaccine side effects while, remarkably, antibody levels continued to increase up to the six-month mark.”