G-MPJTWV00TX Nasal spray could prevent Covid infection for up to eight hours and effective against ALL variants of the virus - Science/News
  • August 18, 2022

Nasal spray could prevent Covid infection for up to eight hours and effective against ALL variants of the virus

Nasal spray could prevent Covid infection

Why YSK: A molecule developed by researchers at the University of Helsinki can inactivate the coronavirus spike protein and offers effective short-term protection against the virus.

Cell cultures and animal studies show that TriSb92, a new molecule developed by the researchers, protects against coronavirus infection for at least eight hours even in cases of high exposure risk. In contrast to vaccine protection, the effect of TriSb92 begins immediately after its administration.

“In animal models, nasally administered TriSb92 offered protection against infection in an exposure situation where all unprotected mice were infected,” says Postdoctoral Researcher Anna Mäkelä, the first author of the study.

The findings have been published in an as of yet non-refereed report.

Targeting the Achilles heel of the coronavirus

The TriSb92 molecule is based on an entirely new technical solution developed in Finland for targeting biological drugs. In the study carried out at the University of Helsinki, this solution was utilised to inhibit the functioning of the spike protein on the surface of the SARS-CoV-2 virus.

“Targeting this inhibitory effect of the TriSb92 molecule to a site of the coronavirus spike protein common to all variants of the virus makes it possible to effectively inhibit the ability of all known variants, Omicron included, to infect people,” Mäkelä explains.

In model virus studies, TriSb92 was able to prevent even the spread of SARS, the virus that threatened us in the early 2000s.

“In other words, we can fairly confidently assume that future variants of SARS-CoV-2 and perhaps even entirely new coronaviruses that may threaten to cause pandemics are susceptible to it,” Mäkelä confirms.

The product, which is nasally administered, could in the future serve as a kind of biological protection against coronavirus infection that is sprayed on the mucous membranes.

Vaccines still needed

Mäkelä works in Professor Kalle Saksela’s laboratory at the University of Helsinki. Saksela is involved in the development of a Finnish nasally administered coronavirus vaccine, which is expected to progress to clinical trials in the spring. Mäkelä and Saksela emphasise that, instead of competing with them, TriSb92 is a solution that supplements vaccines.

“These types of molecules that prevent infections, or antiviral drugs for that matter, cannot substitute for vaccines in protecting the population against the coronavirus disease,” Saksela points out. 

However, there is a great need for novel means with which to enhance the protection provided by vaccines.

“Individuals whose immune system does not respond strongly enough to vaccines spring to mind in particular. Having said that, we know that new variants, especially Omicron, are capable of circumventing even effective vaccine responses worryingly well. Taken before any kind of social interaction, TriSb92 could be useful to people whose vaccine protection is insufficient for one reason or another. Depending on the epidemic situation, it could also benefit fully vaccinated individuals when administered before any situation associated with a high risk of exposure,” Saksela assesses.

A new nasal spray treatment may be able to give high-risk people immunity from COVID-19 for a short period of time.

The treatment, under development by scientists at the University of Helsinki, in Finland, has shown an ability to block coronavirus infection for up to eight hours in lab studies.

It hasn’t yet been tested in humans and the lab studies are not yet peer reviewed.

This nasal spray is intended for use by immunocompromised patients and others with severe vulnerabilities to Covid.

It works by blocking the virus from replicating in the nose and, in lab studies, has performed well against all variants – unlike popular monoclonal antibody treatments that are less effective against Omicron.

While the treatment can’t replace vaccines, it can provide additional protection for those who need the extra immune system boost and may be a basis for other future treatments.

Immunocompromised people have weakened immune systems due to cancer treatment, organ transplants, HIV infections, and other conditions.

These people are highly vulnerable to severe Covid symptoms – and the typical vaccine series may not give their immune systems enough of a boost to effectively protect against the virus.

As a result, the Centers for Disease Control and Prevention (CDC) recommends that all immunocompromised Americans over age five receive an additional vaccine dose.

In the coming months, the agency may also recommend that immunocompromised people get a fourth shot.

In addition to continued vaccinations, many researchers are now pursuing treatments specifically for immunocompromised and other high-risk people that can supplement vaccination.

For example, in December, the Food and Drug Administration (FDA) authorized a monoclonal antibody treatment made by AstraZeneca that’s designed to prevent Covid infection in high-risk patients.

A new nasal spray treatment, under development by scientists at the University of Helsinki, may also become a useful option for these patients.

The treatment was described in a preprint posted in late December, which has not yet been peer reviewed.

‘Its prophylactic use is meant to protect from SARS-CoV-2 infection,’ Kalle Saksela, virologist at the University of Helsinki and lead author on the study, told Gizmodo in an email.

‘However, it is not a vaccine, nor meant to be an alternative for vaccines,’ Saksela said, ‘but rather to complement vaccination for providing additional protection for successfully vaccinated individuals in high-risk situations, and especially for immunocompromised persons – for example, those receiving immunosuppressive therapy.’

The new drug builds on previous research showing that tissue inside the nose is a prime spot for the coronavirus to replicate. 

After multiplying in the nose, the virus typically progresses through the respiratory tract to the lungs – where it causes more severe symptoms.

As a result, sending anti-Covid antibodies straight into the nose can stop the virus from replicating at the earliest possible stage of disease.

The Helsinki researchers’ treatment uses a type of lab-made antibodies, similar to monoclonal antibodies.

Unlike monoclonal antibodies, however, the immune system particles used in the treatment are smaller and more versatile.

These antibodies are engineered from a piece of the virus that has hardly changed across different variants and viral strains.

To increase the nasal spray’s potential for neutralizing Covid, the researchers packed three of these antibodies together into one drug.

The researchers first tested their drug against pseudoviruses – lab-made viruses that mimic the coronavirus.

In this test, the drug was able to stop viral replication in the original Wuhan strain, as well as the Beta, Delta, and Omicron variants.

Next, the researchers tested the drug against human cells in cell culture. Once again, it was able to neutralize several different coronavirus variants.

Finally, the researchers tested the drug in mice – administering the nasal spray to lab mice, then following it up with nasal inoculations of the coronavirus.

Among the mice that didn’t receive treatment, the coronavirus spread through their nasal cavities, respiratory tracts, and lungs.

Among the mice that did receive the nasal spray, the coronavirus didn’t spread at all – these animals were ‘entirely free of viral antigen’ and didn’t show symptoms, the researchers wrote.

This study has yet to be peer reviewed, and many more steps are needed before the nasal spray can be tested in humans. 

The spray could be considered a drug by some countries’ regulatory agencies and a medical device by others, which may complicate the process for getting it approved.

Lead author Saksela was optimistic about the drug’s potential in an interview with Gizmodo.

‘This technology is cheap and highly manufacturable, and the inhibitor works equally well against all variants,’ he said.

‘It works also against the now-extinct SARS virus, so it might well also serve as an emergency measure against possible new coronaviruses (SARS-CoV-3 and -4).’

The monoclonal antibody treatments commonly used in the U.S. are less effective against Omicron than they were against past virus strains.

This nasal spray, however, should be effective against Omicron and other new variants, because it’s based on a part of the virus that has not changed during mutation.

In addition to Covid treatments, the Helsinki researchers may pursue similar sprays for other respiratory infections.

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Nasal spray could prevent Covid infection for up to eight hours

Sources:- ncbi.nlm.nih.gov

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