Covid nasal sprays may one day prevent and treat infection

PTI, Nov 29, 2022, 9:10 AM IST

AFP photo (for representation)


We have vaccines to boost our immune response to SARS-CoV-2, the virus that causes Covid. We have medicines you can take at home (and in hospital) to treat Covid. Now researchers are trialling something new.

They want to develop drugs that stop the virus getting into the body in the first place. That includes nasal sprays that stop the virus attaching to cells in the nose.

Other researchers are looking at the potential for nasal sprays to stop the virus replicating in the nose, or to make the nose a hostile place to enter the body.

Here’s where the science is up to and what we can expect next.

How could we block the virus?

Viral blockade, as the name suggests, is a simple premise based on blocking SARS-CoV-2. In other words, if something gets in its way, the virus cannot attach to a cell and it can’t infect you.

As SARS-CoV-2 is a respiratory virus, it makes sense to deliver this type of medicine where the virus mainly enters the body via the nose, in a nasal spray.

There are various groups around the world working on this concept. Some research is still being conducted in the lab. Some agents have progressed to preliminary human trials. None are yet available for widespread use.


Heparin is a common medicine that’s been used for decades to thin the blood. Studies in mice show that when heparin is delivered via the nose, it’s safe and effective in preventing the virus binding to nose cells. Researchers believe heparin binds to the virus itself and stops the virus attaching to the cells it’s trying to infect.

A clinical trial is being conducted in Victoria in collaboration between multiple Melbourne-based research centres and the University of Oxford.


Covixyl-V (ethyl lauroyl arginine hydrochloride) is another nasal spray under development. It aims to prevent Covid by blocking or modifying the cell surface to prevent the virus from infecting.

This compound has been explored for use in various viral infections, and early studies in cells and small animals has shown it can prevent attachment of SARS-CoV-2 and reduce the overall viral load.


This molecule, which is extracted from seaweed, acts by blocking virus entry into airway cells.

One study of about 400 health-care workers suggests a nasal spray may reduce the incidence of Covid by up to 80 per cent.


This is an engineered antibody that binds to SARS-CoV-2, blocking the virus from attaching to cells in the nose.

A nasal and oral (mouth) spray are in a clinical trial to assess safety.

Cold atmospheric plasma

This is a gas that contains charged particles. At cold temperatures, it can alter the surface of a cell.

A lab-based study shows the gas changes expression of receptors on the skin that would normally allow the virus to attach. This results in less SARS-CoV-2 attachment and infection. Scientists now think this technology could be adapted to a nasal spray to prevent SARS-CoV-2 infection.

How could we stop the virus replicating?

Another tactic is to develop nasal sprays that stop the virus replicating in the nose.

Researchers are designing genetic fragments that bind to the viral RNA. These fragments known as locked nucleic acid antisense oligonucleotides (or LNA ASOs for short) put a proverbial spanner in the works and stop the virus from replicating.

A spray of these genetic fragments delivered into the nose reduced virus replication in the nose and prevented disease in small animals.

How could we change the nose?

A third strategy is to change the nose environment to make it less hospitable for the virus.

That could be by using a nasal spray to change moisture levels (with saline), alter the pH (making the nose more acidic or alkaline), or adding a virus-killing agent (iodine). Saline can reduce the amount of SARS-CoV-2 in the nose by simply washing away the virus. One study has even found that saline nasal irrigation can lessen Covid disease severity. But we would need further research into saline sprays.

An Australian-led study has found that an iodine-based nasal spray reduced the viral load in the nose. Further clinical trials are planned.

One study used a test spray containing ingredients including eucalyptus and clove oils, potassium chloride and glycerol. The aim was to kill the virus and change the acidity of the nose to prevent the virus attaching.

This novel formulation has been tested in the lab and in a clinical trial showing it to be safe and to reduce infection rate from about 34 per cent to 13 per cent when compared to placebo controls.

Barriers ahead

Despite promising data so far on nasal sprays for Covid, one of the major barriers is keeping the sprays in the nose. To overcome this, most sprays need multiple applications a day, sometimes every few hours.

So based on what we know so far, nasal sprays will not singlehandedly beat Covid. But if they are shown to be safe and effective in clinical trials, and receive regulatory approval, they might be another tool to help prevent it.


(By Lara Herrero, Research Leader in Virology and Infectious Disease, Griffith University for The Conversation)

Udayavani is now on Telegram. Click here to join our channel and stay updated with the latest news.

Top News

TMC protects infiltrators, opposes CAA: PM Modi

Bengaluru: Woman cheated on pretext of marriage; complaint filed

Kerala High Court CJ hospitalised due to uneasiness during visit to Mahakaleshwar temple in MP

‘My name is Arvind Kejriwal and I’m not a terrorist’: AAP shares Delhi CM’s message from Tihar

Not found it correct to take step that could overlap legal process: EC

BJP believes in winning hearts; ‘lotus’ will bloom on its own: Amit Shah to Kashmiris

Lok Sabha polls 2024: Opposition calls Sanatana dharma ‘dengue and malaria’…must be punished, says Modi

Related Articles More

Surgical options for Parkinson’s disease

Breast cancer to cause a million deaths a year by 2040: Lancet commission

Will to resist temptations, achieve goals more trustworthy than using apps, study finds

Govt directs e-commerce firms to remove drinks, beverages from ‘health drinks’ category

Experiencing abuse, neglect as child linked to lifelong ill-health: Study


Grafting Jack Anil

Heat Illness

Dwarakish death at 81

H. D. Deve Gowda

Aura Cake shop in udupi

Latest Additions

No discrimination with Muslims under PM Modi: Anurag Thakur

India aims to achieve debris-free space missions by 2030: ISRO chief Somanath

Delhi HC rejects plea against winding up Maulana Azad Education Foundation

Mudigere: People will teach ‘resolute’ lesson for 10 years’ misdeeds: Jayaprakash Hegde

Indian Coast Guard rescues stranded fishing boat off Karwar

Thanks for visiting Udayavani

You seem to have an Ad Blocker on.
To continue reading, please turn it off or whitelist Udayavani.