Before the start of the Lunar New Year in January, Chinese officials reported an outbreak of a lung infection from a market in the city of Wuhan. At the time, there were about 41 cases of infection and one fatal disease associated with an unknown coronavirus.
Some thought it was similar to the SARS virus, short for severe acute respiratory syndrome. The virus struck southern China in late 2002 and then spread to more than 24 countries, killing nearly 800 people.
Others have compared the new virus to MERS, a Middle Eastern respiratory syndrome. The coronavirus was first reported in 2012 in Saudi Arabia before it spread to 27 countries and led to 858 known deaths.
The emergence of SARS and MERS is largely contained. But there is still no vaccine for these diseases.
Vaccine development
Vaccine development is a long and complex process. It took 18 years for scientists to successfully develop a vaccine against polio, a disease that paralyzed many children. A college of doctors from Philadelphia said it took two to four years just to identify in the lab a substance that can fight the disease.
But this outbreak was different. In just two months, the new coronavirus has infected more than 118,000 people in 114 countries. More than 4,200 died from the disease.
The World Health Organization (WHO) declared the new coronavirus a pandemic on March 11. Around the world, scientists immediately set to work on developing a vaccine based on the genetic structure of the new coronavirus published on virological.com.
The WHO says there are currently more than 50 candidates for the COVID-19 vaccine on human tests. At least 12 trials are in Phase 3 with as many as 40,000 volunteers.
This month, the United States, Britain and the European Union approved the first two vaccines, developed by Pfizer-BioNTech and Moderna, for emergency use against the new coronavirus. Approval followed less than a year after the pandemic began.
The U.S. Food and Drug Administration (FDA) has determined that two vaccines from Pfizer-BioNTech and Modern are 95 percent safe and effective against COVID-19. The rate is well above the requirement that the vaccine be at least 50 percent effective to be considered for emergency use.
Dr. Anthony Fauci is the U.S. government’s chief infectious disease expert. He said, “Not many people expected it to be so high.”
mRNA technology
The American drug manufacturer Pfizer is one of the world’s largest companies. Modern is a small biotechnology company that has not launched any product on the market.
But the two drug manufacturers have one thing in common. They both used a technology called messenger RNA, or mRNA, to develop vaccines in record time.
Traditional vaccines usually inject an inactive or attenuated virus into the body to force the production of antibodies to fight the virus. Vaccines from Pfizer and Moderna do not contain the coronavirus itself.
Vaccines against mRNA instruct our cells to make what is called “spike protein”, a substance found on the surface of the virus that causes COVID-19. Then the cell breaks the instructions and solves them. The human body recognizes that the protein does not belong there and begins to produce antibodies to fight COVID-19. At the end of the process, the body learns how to protect itself from future infection.
The advantage of mRNA vaccines is that those who are vaccinated gain protection without the risk of contracting COVID-19.
Research behind technology
To date, no mRNA vaccine has been approved for human treatment. But technology research began almost 30 years ago.
In 1990, University of Pennsylvania scientist Katalin Kariko proposed the use of mRNA technology in the gene therapy. It was hard to work with technology at the time. When she injected genetic material into laboratory mice, some died.
Kariko worked with colleague Drew Weissman. They made an important discovery in 2005. They replaced one of the four chemical building blocks of mRNA with a slightly modified substance called pseudouridine. Weissman said, “We delivered it for patent, and that was the birth therapeutic RNA. “
Karik and Weissman’s findings, however, did not receive much attention until 2010. That year, Harvard University scientist Derrick Rossi used modified mRNA in his stem cell research. Rossi, along with several others, licensed technology to establish a new manufacturer of biotech drugs called Moderna. The name is a combination of the words modified and RNA. Karikó now works for BioNTech overseeing the development of its mRNA product.
On December 8, Britain’s Margaret Keenan became the first person in the world to receive a tested and approved COVID-19 vaccine from Pfizer-BioNTech.
Keenan, who was due to turn 91 next year, said: “It’s the best early birthday gift I could wish for, because it means I can finally look forward to hanging out with family and friends in the New Year after I’ve been alone for the most part years. “
Around 74 million people worldwide are infected with the new coronavirus. Nearly 1.7 million died from COVID-19.
I’m Caty Weaver. And I’m Mario Ritter Jr.
Hai Do wrote this story for VOA Learning English. Mario Ritter Jr. he was an editor.
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The words in this story
paralyzed –Adj. unable to feel or move body parts
Phase 3 –N. the level of development of the vaccine when it is tested on humans to better understand their reactions
therapy –N. disease treatment
delivered –V. offered for review and approval
patent –N. an official document that entitles a person to be the sole seller of a product for a specified period of time
therapeutic –Adj. related to treatment and therapy
licensed –V. having an official license to get something or to make a profit from it
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