Italy alerts public to mosquito bite risks and refutes vitamin B1 repellent myth

Mosquitoes are returning in large numbers across Rome, Pomezia, Ostia, Torvaianica and the wider Lazio coast as summer begins. Stagnant water in gardens, pools and urban sewers creates ideal breeding sites, leading to frequent bites that cause itching, redness and swelling. While most reactions are mild and resolve in a few days, severe local inflammation, infections from excessive scratching, or systemic symptoms such as fever and muscle aches may require medical attention.

Scientific reviews have examined the long‑standing claim that high doses of vitamin B1 (thiamine) act as a systemic mosquito repellent. Controlled double‑blind studies, including those by researchers at the University of California’s Department of Dermatology, found no reduction in mosquito landings or bite rates after oral or parenteral vitamin B1 administration. The myth, originating from a 1943 report, persists despite a lack of evidence. Effective protection relies on personal measures—eliminating standing water, using proven insect repellents, and covering exposed skin—rather than vitamin B1 supplementation.