Not all viruses are created equal: they can benefit humanity

The reputation of viruses is understandably not very good. At best, they are perceived as the cause of colds and high fever. In the worst case scenario, they are the culprits of mass extinction and the “zombie apocalypse”. But there are viruses that not only do not harm us, but, on the contrary, help. Here are some examples of how they do it.

Kill bacteria

Bacteriophages are a type of virus. They attack and destroy certain bacteria. According to scientists, bacteriophages are part of our natural immunity. Some of these viruses live right in our body, in particular in the mucous membrane that lines the digestive tract, respiratory and reproductive systems.

For nearly a hundred years, bacteriophages have been used successfully to treat dysentery, as well as infections caused by Staphylococcus aureus and Salmonella. Doctors took viruses in their natural habitat: from water bodies, mud, and even from the biological fluids of an infected person.

A new wave of interest in bacteriophages has arisen due to the fact that some infectious diseases do not respond to antimicrobial therapy. In Great Britain, there was a case when nothing helped a patient at all and bacteriophages were the only salvation.

Now they are synthesized artificially and tested to fight specific infections. Sometimes several strains are combined to obtain a broader spectrum of action. It is believed that bacteriophages work more precisely, point-wise, and have fewer side effects than antibiotics.

Compete with more dangerous viruses

Some viruses protect people from more dangerous infections and other diseases. For example, the GBV-C virus (formerly called hepatitis G), according to several studies, "conflicts" with HIV, attaching to cellular receptors instead of it and stimulating the immune response.

This, unfortunately, does not prevent HIV infection, but those infected who are also found to have GBV-C live longer. GBV-C itself is also not entirely harmless, but responds well to treatment and is often asymptomatic.

Attack cancer cells

There are even more impressive examples of how viruses save people. Scientists have found that the causative agent of herpes simplex, paradoxically, is effective in the treatment of cancer.

In 2015, Imligik, a drug containing a genetically modified herpes simplex virus, was approved as a treatment for metaplastic melanoma, a malignant tumor that is localized in the cells of the skin and mucous membranes.

There is also a small but promising study that shows that the causative agent of herpes can fight against glioblastoma cells - a brain tumor.

Firstly, viral particles literally attack cancer cells and destroy them, and secondly, they “warn” the immune system, in particular T-lymphocytes, about the danger (without a virus, cancer cells often go “unnoticed”).

Doctors have created a special type of herpes pathogen - this microorganism must attack only cancer cells and remain safe for healthy people. During treatment, viral particles are injected directly into the tumor. This method of action is called oncolytic viral immunotherapy, and it shows encouraging results: in several patients, the tumor size after the use of modified viral particles decreased markedly. True, the technique requires study and is not yet widely used.

Repair "broken" genes

When viruses attack the human body, they integrate directly into the cell, transfer their genetic material into it and use its resources to reproduce their own copies.

In the 1970s, scientists decided that this mechanism could well be used for the benefit of humanity. After all, if viruses can penetrate into a cell, then they can bring something useful there. This is how the idea of gene therapy for hereditary and other serious diseases began to develop.

Simplified, it looks like this. With the help of viral vectors (most often these are microbes modified in laboratories from among those relatively safe for humans), the "correct" genetic material is sent to the patient's body. The virus brings this "medicine" directly into the cell, and its genetic information changes. As a result, it begins to function as it should and, after division, forms renewed, corrected cells instead of diseased ones.

Alas, gene therapy is not widely used yet. Due to the complex mechanism of action, only a few drugs have successfully passed clinical trials, and they are fabulously expensive. But the successes of scientists are still impressive.

For example, in 2019, the drug Zolgensma, created using viral particles, entered the market. It is used to treat spinal muscular atrophy, a severe, incurable hereditary disease that affects motor neurons and gradually loses the ability to move. Zolgensma costs more than $ 2.1 million per injection, it is the most expensive single-use drug in the world.

The potential for gene therapy is very broad. It is assumed that with its help it will be possible to treat not only hereditary pathologies, but also many other chronic diseases, including mental disorders.