September 10, 2022 01:54
By the time a patient knows they have COVID-19, the novel coronavirus has already settled in the respiratory tract. With each breath, the infected expels invisible viral particles into the air.
Even if current medications work to treat symptoms of the virus, they do little to prevent the virus from shedding, which leads to transmission of the infection to other people.
To counter this dilemma, researchers have developed a new approach to treating infectious diseases: a single dose of intranasal therapy helps protect against infection with the coronavirus.
In a new study published in the Proceedings of the National Academy of Sciences, researchers show that this new treatment, called therapeutic interfering particle, TIP, also reduces the amount of virus released from infected animals and limits virus transmission.
“Historically, it has been exceptionally difficult for antiviral drugs and vaccines to reduce transmission of respiratory viruses, including SARS-CoV-2,” says lead researcher and American virologist Lior Weinberger, senior author of the new paper. The study found that a single dose of intranasal TIPs reduces the amount of virus transmitted and protects animals that have come into contact with that treated animal.”
“To our knowledge, this is the only antiviral that not only reduces symptoms and severity of COVID-19, but also reduces virus shedding from the patient,” says Sonali Chaturvedi, researcher and first author of the paper.
Viruses, such as coronavirus as well as influenza and HIV, evolve over time, become drug-resistant and it is difficult to develop long-term treatments. More than two decades ago, Weinberger first proposed the idea of therapeutic interfering particles (TIPs) to treat viruses. Instead of directly targeting a portion of the virus, the intervening therapeutic particles compete for resources in an infected cell. By depleting the transcription machinery inside the cell, interfering therapeutic particles can prevent the virus from making more copies of itself.
However, the usefulness of interfering therapeutic particles goes beyond their ability to stifle virus within infected cells. Because the interfering therapeutic particles are present within the same cells that the virus targets, they evolve at the same time, remaining active even as new viral strains emerge.
“Over the past few years, many of the challenges of the epidemic have been associated with the emergence of new variants,” Chaturvedi says, stressing that “therapeutic interfering particles can be an ideal treatment because they continue to learn as the virus evolves, so that it can control the problem of drug resistance.”
Even before the COVID-19 pandemic, Weinberger’s group was already working on the development of therapeutic interfering particles to treat HIV. In 2020, they quickly switched to applying this technology to the coronavirus as they developed a single dose of intranasal therapeutic particle against the virus.
Last year, the research team reported that during experiments on rodents, the interfering therapeutic particles were able to successfully block many different variants of the Corona virus, reducing the viral charge in the lungs by 100 times and reducing many symptoms of the disease.
During the research, Weinberger, Chaturvedi and their team studied whether interfering therapeutic particles could also reduce viral shedding, which is a separate question from reducing symptoms and viral load.
Researchers treated rodents infected with MERS-CoV with interfering antiviral particles, and then measured, daily, the amount of virus in the animals’ noses. Compared with animals that did not receive the interfering therapeutic particles (called controls), the treated animals had fewer viruses in their sinuses at each time point. By the fifth day, all control animals still excreted high levels of virus, while virus was undetectable in four out of five animals treated with the interfering therapeutic particles.
“We know that the amount of virus shed is proportional to how infected a person is,” Weinberger says. “If the spread of the virus can be reduced, it is also likely that the number of secondary contacts that are likely to become infected will decrease, which in turn will lead to Reduce the spread of the virus in general and help keep vulnerable individuals safe.”
When animals infected with MERS-CoV were placed in cages with uninfected animals, treatment of infected animals with interfering therapeutic particles did not completely prevent transmission of COVID-19. However, it resulted in a significant decrease in viral loads and milder symptoms in exposed animals.
Although the initial experiments were conducted on the “delta” strain of the emerging corona virus, the researchers repeated the tests using the first strain of the virus and confirmed that the same overlapping therapeutic particles were effective for the variants.
Weinberger’s team is now seeking FDA approval for a clinical trial to test NTPs in humans.
Source: Al Ittihad – Abu Dhabi
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