Starting twice daily flushing of the nasal cavity with a mild saline solution soon after testing positive for Covid-19 may reduce hospitalisation due to the viral disease, a study claims.
The technique involves mixing a half teaspoon each of salt and baking soda in a cup of boiled water and then putting it into a sinus rinse bottle, making it a safe, effective and inexpensive way that can have a vital public health impact.
"By giving extra hydration to your sinuses, it makes them function better," said Amy Baxter, from Augusta University, US.
"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," said Baxter, corresponding author of the study.
The research, published recently in Ear, Nose & Throat Journal found an 8.5-fold reduction in hospitalisations and no fatalities compared to controls.
Less than 1.3 per cent of the 79 subjects aged 55 and older who enrolled within 24-hours of testing positive for Covid-19 between September 24 and December 21, 2020, experienced hospitalisation, and no one died, the researchers said.
Among the participants, who were treated and followed for 28 days, one participant was admitted to the hospital and another went to the emergency room but was not admitted, they said.
By comparison, 9.47 per cent of patients were hospitalised and 1.5 per cent died in a group with similar demographics reported by the US Centers for Disease Control and Prevention during the same timeframe, according to the researchers.
"If confirmed in other studies, the potential reduction in morbidity and mortality worldwide could be profound," they said.
The SARS-CoV-2 virus is known to attach to the ACE2 receptor, which is pervasive throughout the body and in abundance in locations like the nasal cavity, mouth and lungs.
Drugs that interfere with the virus' ability to attach to ACE2 have been pursued, and Baxter said the nasal irrigation with saline helps decrease the usual robust attachment.
Saline appears to inhibit the virus' ability to essentially make two cuts in itself, called furin cleavage, so it can better fit into an ACE2 receptor once it spots one.
Participants self-administered nasal irrigation using either antiseptic povidone-iodine, or baking soda, mixed with water that had the same salt concentration normally found in the body.
While the researchers found the additives really added no value, previous research had indicated they might help, for example, make it more difficult for the virus to attach to the ACE2 receptor.
However, the research indicates the saline solution alone sufficed.
"It is really just the rinsing and the quantity that matter," Baxter said.
The researchers also wanted to know any impact on symptom severity, like chills and loss of taste and smell.
Twenty-three of the 29 participants who consistently irrigated twice daily had zero or one symptom at the end of two weeks compared to 14 of the 33 who were less diligent, the researchers said.
Those who completed nasal irrigation twice daily reported quicker resolution of symptoms regardless of which of two common antiseptics they were adding to the saline water, they said.
Sixty-two of the participants completed a daily survey, reporting 1.8 irrigations daily; 11 reported irrigation-related complaints and four discontinued use.
Other studies have shown the nasal irrigation, also called lavage, can also be effective in reducing duration and severity of infection by a family of viruses that include the coronaviruses, as well as the influenza viruses, the researchers added.
