The mineral zinc has been used to treat colds for decades, with its efficacy supported by clinical trials and commercial products available to the public. A new trial has now linked zinc, delivered orally, to reduced severity and length of SARS-CoV-2 infections.
In a randomized controlled trial published in Clinical Infectious Diseases, patients who took oral zinc twice daily for 15 days had a 42% reduced likelihood of death and intensive care unit admission (30-day mortality was 6.5% in zinc group and 9.2% in placebo group). They also had shorter hospital stays and duration of illness, investigators reported. No evidence of severe adverse events was found during the study.
The trial took place across multiple health centers in Tunisia. Participants tested positive for COVID-19 and none had end organ failure. Forty percent were ambulatory and 60% were hospitalized. Among the participants, 231 were randomized to receive oral zinc and 239 received a matching placebo.
Zinc taken orally may help to treat colds when given within 24 hours of symptom onset, according to the National Center for Complementary and Integrative Health, referring to a 2015 analysis of clinical trials. But oral zinc has also been associated with uncomfortable side effects, including nausea and other gastrointestinal symptoms, the agency noted.
Zinc may also interact with antibiotics and with the drug penicillamine, used to treat rheumatoid arthritis, the NCCIH cautioned.