新冠疫苗的成功让资源走向mRNA

From VOA Learning English, this is the Health & Lifestyle report.

The success of COVID-19 vaccines based on messenger RNA (mRNA) is increasing the use of the new technology on other medical treatments. And scientists say that mRNA could possibly target diseases that do not respond to other drugs.

Last December, the United States Food and Drug Administration and European health agencies approved the first two coronavirus vaccines from Pfizer-BioNTech and Moderna. They both used mRNA to develop the vaccines in record time. Health officials also found the two vaccines to be safe and 95 percent effective against COVID-19. This is well above the requirement to be considered for emergency use.

The mRNA technology is often likened to the operating system on a computer. It permits drug makers to change their target by putting new genetic code into a manufactured form of mRNA.

In the coronavirus vaccine, the code gives instructions for our cells to make what is called the "spike protein," a substance found on the surface of the virus that causes COVID-19. The cell then breaks down the instructions and gets rid of them. The human body recognizes that the protein does not belong there and starts producing antibodies to fight against COVID-19. At the end of the process, the body learns how to protect against future infection.

More money coming to mRNA development

Glenn Hunzinger is with the firm PricewaterhouseCoopers. He told Reuters news agency, "There is more attention and focus on mRNA now that it has proven to be a technology that works."

During the pandemic, more than $5.2 billion was invested in companies that were developing mRNA vaccines and other treatments. This amount is up from $596 million from 2019. These numbers come from the research firm Roots Analysis.

Roots Analysis say over 150 mRNA vaccines and treatments are in development around the world. Most are still in early animal testing. And more than 30 have reached human testing.

Most of last year's money went to COVID-19 projects. But this also permitted companies to research other diseases. For example, Moderna is working on treatments for heart disease, cancer, and rare diseases. Its most advanced non-COVID program is a vaccine for cytomegalovirus, the leading cause of birth defects in the U.S.

mRNA could be difficult to work with

However, mRNA can be very difficult to work with. This makes future successes with treatments uncertain.

Dr. Drew Weissman is a professor at the University of Pennsylvania's Perelman School of Medicine. He and Hungarian-born scientist Katalin Karikó are credited with an important discovery in 2005 that enables the use of mRNA technology in medicine.

At the time, mRNA was difficult to work with and not approved for medical treatment. When they injected lab mice with the genetic material, some died. The two then replaced one of mRNA's four chemical building blocks with a slightly modified substance called pseudouridine in order to get it past the body's defenses.

Instructions from mRNA are brief and non-specific about where in the body it goes. This works well when telling cells to make a harmless substance to force the production of antibodies against the virus.

It is more difficult to send those orders to a specific tissue, like the lungs or heart muscle. This requires different delivery methods to protect the somewhat weak mRNA molecule.

Translate Bio is a Massachusetts-based company working on an mRNA treatment for cystic fibrosis, a life-shortening lung disease. People with this disease cannot produce protein to fight lung infections and other serious health issues.

The drug-maker aims to become the first company to bring an mRNA drug to market. Last week, Translate Bio released some results from its ongoing drug trials. The results showed no clear improvement among patients receiving the experimental drug.

Most drugs treat the effects of the disease. However, "mRNA is in the business of replacing what's missing," said Joe Payne. He is the head of Arcturus. That company is currently working to develop mRNA vaccines for COVID-19 and influenza, as well as medicines for liver disease and cystic fibrosis.

What's next for mRNA?

With FDA acceptance of the vaccines, experts say top scientists are also moving to the field of mRNA study.

Karikó now works for BioNTech. She supervises development of its mRNA product. And Weissman said 20 companies working in the field of mRNA have asked him to join their boards of directors.

And that's the Health & Lifestyle report.

I'm Anna Matteo and I'm Dan Friedell.

Deena Beasley reported this story for Reuters. Anna Matteo and Hai Do added additional information for VOA Learning English. Hai Do was also the editor.