A nasal spray that temporarily helps to shield people from Covid-19 is currently being developed by scientists at the University of Birmingham in the UK.
It works by coating the inside of the nose with special sticky compounds that help to stop the virus from entering the body. The idea is that people could squirt the spray up their nostrils if they’re about to enter a high-risk environment where social distancing is not possible, such as a hospital or on an airplane, to help add a second layer of protection against the virus. So the theory goes, the spray would temporarily reduce the risk of a person's respiratory tract being infected with Covid-19 by blocking the virus from being uptaken by the body. This could also reduce the chances of a potentially infected person passing the virus on to someone else by reducing the viral load in their body.
It’s still very early days for the research, though. Described in a new pre-print paper — meaning it's not yet peer-reviewed — the idea has been tested out on cell culture experiments designed to assess the ability of the solution to inhibit infection in the lab. Further trials in humans are still needed to see whether the nasal spray actually works in practice, but the team has shown that the solution was effective at inhibiting SARS-CoV-2, the coronavirus that causes Covid-19, for up to 48 hours in a petri dish. Whether it remains this effective while it's up a person's nose and out in the real world remains unclear for now.
Optimistically, most of the ingredients are already widely used in medicines and food products, suggesting it could become available to the public with relative ease if follow-up tests go well. The key compound of the nasal spray is carrageenan, a polysaccharide with antiviral properties that comes from red seaweed and is commonly used as a thickening agent in food. It also employs the help of another polysaccharide known as gellan, a common food additive that helps the spray stick to the nasal cavity.
“This spray is made from readily available products that are already being used in food products and medicines, and we purposely built these conditions into our design process,” Dr Richard Moakes, lead study author, said. “It means that, with the right partners, we could start mass production within weeks.”
The authors pointed out this spray wouldn't replace vital measures that help prevent transmission such as wearing a mask and washing your hands. “What this spray will do, however, is add a second layer of protection to prevent and slow virus transmission,” Dr Moakes said.
Several other projects are developing nasal sprays that work on a similar principle. Researchers at Stanford University are working on nasal drops that use chicken antibodies to provide protection against Covid-19 by capturing and neutralizing the coronavirus. An Australian biotech company has also won million-dollar funding to develop their INNA-051 nasal treatment, which helps to reduce the risk of being infected with respiratory infections, including Covid-19.