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 the hospital) to treat COVID. Now researchers are trying something new.
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 the hospital) to treat COVID. Now researchers are trying something new.
They want to develop a drug that stops the virus before it can enter the body. This includes nasal sprays that prevent the virus from attaching to cells in the nose.
Other researchers are looking into the potential of nasal sprays to prevent viruses replicating in the nose or to make the nose a hostile place to enter the body.
Here's where the science is at and what we can expect next.
How can we stop the virus?
"Viral blockade", as the name suggests, has a simple premise based on blocking SARS-CoV-2. In other words, if something gets in its way, the virus can't attach to a cell and it can't infect you.
Since SARS-CoV-2 is a respiratory virus, it makes sense to give this type of drug where the virus primarily enters the body – through the nose, in a nasal spray.
Various groups around the world are working on this concept. Some research is still being done in the laboratory. Some agents have progressed to preliminary human trials. None are yet available for widespread use.
heparin
Heparin is a common drug that has been used to thin the blood for decades. Studies in mice suggest that when heparin is given through the nose, it is safe and effective at preventing the virus from binding to nasal cells. Researchers believe that heparin itself binds to the virus and attaches the virus to the cells it is trying to infect.
A clinical trial is being conducted in Victoria in collaboration with several Melbourne-based research centers and the University of Oxford.
covixil-v
Covixyl-V (ethyl lauroyl arginine hydrochloride) is another nasal spray under development. It aims to stop 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 have shown that it can inhibit the association of SARS-CoV-2 and reduce the overall viral load.
iota-carrageenan
This molecule, which is extracted from seaweed, works by blocking the entry of the virus into the cells of the airways.
A study of nearly 400 health-care workers suggests that a nasal spray can reduce the incidence of COVID by 80 percent.
IgM-6268
It is an engineered antibody that binds to SARS-CoV-2, preventing the virus from attaching to cells in the nose.
A nasal and oral (mouth) spray are in clinical trials to assess safety.
cold atmospheric plasma
It is a gas which consists of charged particles. At cold temperatures, it can alter the cell surface.
A lab-based study shows that the gas alters the expression of receptors on the skin that normally allow the virus to attach. This results in less SARS-CoV-2 attachment and infection.
Scientists now think that this technique can be adapted to a nasal spray to prevent SARS-CoV-2 infection.
How can we stop the replication of virus?
Another strategy has been to develop a nasal spray that stops the virus replicating in the nose. Researchers are designing genetic fragments that bind to viral RNA. These fragments – known as "locked nucleic acid antisense oligonucleotides" (or LNA ASOs for short) – put a temporal spanner in the works and stop the virus from replicating. A spray of these genetic fragments reduces virus replication in the nose. and prevented disease in small animals.
How can we change the nose?
The third strategy is to change the nasal environment to make it less hospitable to the virus.
This can be done by using a nasal spray to change the moisture level (with saline), changing 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 also found that saline nasal irrigation can reduce the severity of Covid disease. But we'll need more research into salt spray.
An Australian-led study 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 – which contained ingredients including eucalyptus and clove oils, potassium chloride and glycerol. This was intended to kill the virus and change the acidity of the nose to prevent the virus from attaching.
This novel formulation has been tested in the laboratory.
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