Simply mix a half-teaspoon of salt and a half-teaspoon of baking soda in a cup of boiled (and cooled) or distilled water, then pour it into a sinus rinse bottle. A squeeze bottle or bulb syringe works too.

Dr. Amy Baxter, the study author and emergency medicine physician at the Medical College of Georgia at Augusta University, says providing extra hydration to sinuses makes them function better. 

“If you have a contaminant, the more you flush it out, the better you are able to get rid of dirt, viruses, and anything else,” she says in a press release about the study.

Participants who performed nasal irrigation were more than eight times less likely to be hospitalized than the national rate. About 1.3% of study participants who used nasal irrigation were hospitalized after testing positive for COVID, compared to 9.47% of those who didn’t. Study participants, who were aged 55 and older, were enrolled in the study within 24 hours of a positive PCR COVID-19 test between Sept. 24 and Dec. 21, 2020.

“One of our thoughts was: If we can rinse out some of the virus within 24 hours of them testing positive, then maybe we can lower the severity of that whole trajectory,” says Baxter, who drew inspiration from her visits to Southeast Asia, where nasal irrigation is a regular part of people’s daily personal hygiene regimen. She also noted lower death rates from COVID-19 in countries such as Laos, Vietnam, and Thailand.

As part of the study, participants self-administered nasal irrigation using either povidone-iodine or baking soda. Those who did so twice a day reported “quicker resolution of symptoms,” according to the study.

This is not the first time researchers have found that saline can help combat COVID-19. A 2020 study shows that gargling with a saline-based solution can reduce viral load, while a 2021 study suggests saline can be used as a “first-line intervention for COVID-19.”