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What Is Phage Therapy?

Medically Reviewed by Dan Brennan, MD on January 11, 2023

Phages, or bacteriophages, are viruses that kill certain bacteria. They occur naturally all over the world – in the soil, water, and even in your body. They can fight off bacteria that aren’t able to be killed by other medications. If every antibiotic has failed to help you get over an infection, phage therapy may be able to do the job instead. These viruses can be life saving.

Today, “superbugs,” or bacteria that are resistant to antibiotics, are a real concern. Most antibiotics can’t treat these infections. Experts continue to find more superbugs as time goes on. Without proper treatment, they can have harmful effects on your health and length of life. Because of this, researchers aim to make phage therapy safer and more widely available.

What Does Phage Therapy Do?

Phages aren’t like other viruses that make you sick. They can only infect bacteria. They can’t duplicate on their own. They need bacteria to do so. First, they’ll attach themselves to a bacterium and then insert their DNA into it. This allows the phage to create even more phages.

Doctors can use this natural process to fight infections. With phage therapy, your doctor will look at a library of phages. They’ll choose which one will help your body fight whatever bacteria you have.

Researchers at Yale continue to look at how phage therapy can work alongside antibiotics. They’ve found that it can make current antibiotics work better in your body.

Phage therapy may help with many different issues, such as:

  • Cystic fibrosis
  • Ear infections caused by P. aeruginosa bacteria
  • Infections from E. coli or P. aeruginosa bacteria
  • Infections from leg ulcers
  • Lung infections
  • Eye infections
  • Sepsis in newborns
  • Urinary tract infections
  • Infections in surgical wounds

What Are the Benefits of Phage Therapy?

They target their enemy. Antibiotics kill the thing that causes your infection. But they can also kill many healthy bacteria in your body. Phages, unlike antibiotics, only kill the harmful bacteria. With this therapy, there’s not much damage to other cells in your body.

There’s a huge supply. In the rare case that a phage therapy doesn’t work on your body anymore, there are plenty of other phages to choose from because they’re so common in nature. A resistance to a phage isn’t as bad as a resistance to an antibiotic since antibiotics are limited while there are many phages.

Researchers can develop them quickly. Antibiotics can take years to create. But a specific phage therapy can be made and matched to your illness in a few days. This means that specific treatment for your infection can happen a lot faster than with antibiotics.

Can Phage Therapy Be Harmful?

Just like any other treatment, there are some possible risks with phage therapy:

Lack of information. Most testing with phage therapy has been based on observations. Other studies were very small. So experts still have a lot to learn about how phage therapy can affect you. They don’t fully understand the short and long-term side effects of it. But information from Russia, Poland, and the Republic of Georgia show that it’s likely to be safe for humans when used on your skin.

Risk of septic shock. Doctors are mainly worried about septic shock from phage therapy. When phages break up bacterial cells, they can let off endotoxins. These can affect your immune system and lead to organ failure. But this can also happen with antibiotics.

While it’s a concern, experts haven’t seen many cases of septic shock in people who’ve had phage therapy.

How it interacts with DNA. Phages naturally move DNA from one bacterium to another. One worry with phage therapy is that the movement of DNA will create new harmful bacteria. But experts can stop this if they carefully select the types of phages used for treatment. They’ll make sure these phages don’t have any toxins or harmful factors before they use them.

Can You Get Phage Therapy in the United States?

Today, phage therapy is only available in the United States (and most Western countries) for “compassionate use.” This means that doctors can only use this treatment for emergencies when other approved therapies aren’t available.

While phage therapy has been around for over 100 years, the treatment still isn’t a main part of medicine.

American doctors used it often in the 1940s, but it later fell out of favor by many. There were some issues with how the therapy was regulated and created. Experts also couldn’t agree on how well it worked.

But today, the outlook for phage therapy is good. The Food and Drug Administration (FDA) continues to look into ways to regulate it. The first clinical trial for intravenous (IV) phage therapy gained FDA approval in 2019.

Show Sources

SOURCES:

UC San Diego: “What is Phage Therapy,” “Phage 101.”

American Society of Microbiology: “Phage Therapy: Past, Present and Future.”

Journal of the American Medical Association: “FDA Approves Bacteriophage Trial.”

Yale Medicine: “How Phage Therapy Kills Superbugs: Weaponizing Viruses to Fight Infections.”

Antimicrobial Agents and Chemotherapy: “Bacteriophage Therapy.”

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