A trip to visit family in Kolkata, India, put South Dakota State University assistant professor Saikat Basu in the middle of that country's second wave of COVID-19 infections. However, it also gave the Department of Mechanical Engineering faculty member a unique opportunity to improve delivery of an antiseptic nasal spray that may help reduce the risk of infection.
Basu's research involves modeling the transport of aerosols, including virus-carrying droplets, in the human respiratory tract. "To become infected, you must first inhale the virus, so inhalation patterns are important," Basu explained.
For a National Science Foundation-funded COVID-19 research project, Basu developed a model that uses breathing rates to track which droplets sizes are likely to reach the upper part of the throat behind the nasal passages and above the esophagus and voice box, known as the nasopharynx. Other research studies show viral particles that reach this part of the respiratory tract are most likely to cause infection.
Based on this work, Basu and collaborators from Boston University and Fractal Therapeutics in Cambridge, Massachusetts determined the spray bottle must be held in a near-horizontal position to deliver a virus-fighting povidone-iodine solution into the nasopharynx. Povidone iodine is marketed under the Betadine trademark and has been used as an antimicrobial for more than 20 years.
In the absence of vaccines, there should be other layers of protection and this might be one of them."
Saikat Basu, Assistant Professor, South Dakota State University
He noted getting the spray to the nasopharynx is crucial. The ciliated cells that line the nasopharynx have a surface receptor, known as ACE2, which the novel coronavirus uses to enter the cells. From there, the infection spreads into the lungs.
Basu posted an article on LinkedIn with instructions on how to make a 0.5% povidone-iodine solution as well as a video showing how to position the spray bottle.
"This information could save lives," said Basu, which is why he wanted to quickly share his findings. When compared to the standard vertical spray position, Basu's new spray protocol can result in as much as a hundredfold increase in the amount of antiseptic that reaches the desired location.
Basu and his family, who have not yet received their COVID-19 vaccinations, used the povidone-iodine spray during the five weeks they were in India. Basu's parents are fully vaccinated, but his 82-year-old grandmother is not. "She has been too frail to go out and wait in the long lines at the vaccination centers, many of which have acute shortage of vaccines" he said.
In the LinkedIn article, Basu cites "growing experimental evidence that the povidone-iodine solution works against SARS-CoV-2 (the virus that causes COVID-19)." A spring 2020 study by United Kingdom researchers recommends that the health care professionals and COVID-19 patients use the solution as a nasal spray and a mouthwash. In Singapore, a small National University Health System study found a 25% reduction in SARS-CoV-2 infection among those using the povidone-iodine nasal spray three times a day.
Although no such studies are being conducted in the United States, those who are reluctant or unable to be vaccinated may want to consider using this prevention technique, Basu said. He recommends using three squirts of spray in each nostril "before you are likely to be exposed and then … just after (any possible exposure) again."
Before India's second wave, "some scientists came up with the idea that India had reached herd immunity," Basu explained. India, which is a world leader in vaccine production, even began exporting vaccine to other countries, including Canada.
Now, Basu estimates it will take until the end of 2022 to achieve widespread vaccination in India. An article in The Economist says that may not be accomplished in Africa until 2024.
"This pandemic is not going away any time soon-;the idea is to have better technologies to reduce virus transmission and help protect uninfected populations," Basu said. Proper use of povidone-iodine spray is one way to do that.