A Chilean Tree Gives Hope for New Vaccines
2021-10-12
LRC
TXT
大字
小字
滚动
全页
1Quillay trees are rare evergreens found mainly in the South American country of Chile.
2And they are increasingly important to producing new vaccines.
3The native Mapuche people have long used them to make soap and medicine.
4In recent years, quillay trees, also known as quillaja saponaria, have been used in the processing of food and drinks.
5They have also been used to make a highly successful vaccine against shingles, a painful viral disease, and the world's first malaria vaccine.
6Now, molecules extracted from the bark, or outer covering, of older quillay trees are being used for a COVID-19 vaccine.
7It is being developed by American drug-maker Novavax.
8Over the next two years, Novavax plans to produce billions of treatments of the vaccine for use in developing countries.
9Novavax uses two molecules to make adjuvant, a substance that improves the human immune system.
10One of those, called QS-21, is more difficult to find.
11The substance is found mainly in quillay trees that are at least 10 years old.
12British drug-maker GlaxoSmithKline uses QS-21 in its highly successful vaccine against shingles called Shingrix.
13It is also used in several other promising experimental vaccines.
14The quillay-based adjuvant used in Shingrix is also part of the world's first malaria vaccine, Mosquirix.
15Less than one milligram of quillay extract is required to make a vaccine treatment.
16But the supply of quillay is stretched by the demand from other industries.
17Quillay products are used as a natural additive in animal feed.
18They also are used to kill harmful insects and as an agent to reduce pollution in mining.
19Some drug-makers are developing a manufactured version of QS-21.
20But it could take years to get approval.
21Exchanging the substance for another in any existing vaccine would require new drug tests to prove the product is safe and effective.
22Jason Paragas, a vice president at drug company Agenus, said, "The shortage of QS-21 has been an issue for a while."
23He added, "We saw it before COVID, and we made the hard decision that we had to change."
24The American company in Massachusetts stopped selling the natural version of QS-21 several years ago.
25It now centers on trying to grow it from quillay plant cells in a laboratory.
26Paragas said it is too soon to know when it will be ready.
27Botanical Solution, a California-based company, says it can already produce QS-21 from quillay seeds in the laboratory.
28The company adds that it aims to produce the substance in large quantities for drug companies.
29No one knows how many healthy quillay trees are left in Chile to meet the demand.
30Experts and industry officials believe that they will at some point need to switch to grow the evergreens on farms or in laboratories.
31Ricardo San Martin developed the pruning and extraction process that created the modern quillay industry.
32He said producers must immediately work toward making quillay products from younger, farm-grown trees.
33"My estimate four years ago was that we were heading towards the sustainability limit," he said.
34Quillay producers say the harvest can continue for now without destroying the supply of older trees.
35Novavax told Reuters that the company is working with suppliers to make sure "life-saving vaccines will be prioritized."
36Andres Gonzalez runs Desert King International which operates a quillay farm in Chile.
37It is Novavax's only supplier and the largest quillay exporter in the country.
38He said it produces enough quillay extract from older trees to make up to 4.4 billion vaccine treatments in 2022.
39With new supplies from privately owned forests, he said, the operation can meet demand for the rest of this year and part of the next.
40He admitted, however, that "at some point, these native forests will come to an end."
41Gustavo Cruz is a researcher at the University of Chile who worked with San Martin to industrialize the production of quillay.
42He said he generally trusts quillay producers to deal with supply and demand.
43He is more worried about other threats - especially a lack of water and fire.
44"The trees do eventually regrow," he said, "but there comes a time when they don't anymore."
45I'm Mario Ritter, Jr.
1Quillay trees are rare evergreens found mainly in the South American country of Chile. And they are increasingly important to producing new vaccines. 2The native Mapuche people have long used them to make soap and medicine. In recent years, quillay trees, also known as quillaja saponaria, have been used in the processing of food and drinks. They have also been used to make a highly successful vaccine against shingles, a painful viral disease, and the world's first malaria vaccine. 3Now, molecules extracted from the bark, or outer covering, of older quillay trees are being used for a COVID-19 vaccine. It is being developed by American drug-maker Novavax. Over the next two years, Novavax plans to produce billions of treatments of the vaccine for use in developing countries. 4Making the substance adjuvant 5Novavax uses two molecules to make adjuvant, a substance that improves the human immune system. One of those, called QS-21, is more difficult to find. The substance is found mainly in quillay trees that are at least 10 years old. 6British drug-maker GlaxoSmithKline uses QS-21 in its highly successful vaccine against shingles called Shingrix. It is also used in several other promising experimental vaccines. The quillay-based adjuvant used in Shingrix is also part of the world's first malaria vaccine, Mosquirix. 7Less than one milligram of quillay extract is required to make a vaccine treatment. But the supply of quillay is stretched by the demand from other industries. Quillay products are used as a natural additive in animal feed. They also are used to kill harmful insects and as an agent to reduce pollution in mining. 8Some drug-makers are developing a manufactured version of QS-21. But it could take years to get approval. Exchanging the substance for another in any existing vaccine would require new drug tests to prove the product is safe and effective. 9Jason Paragas, a vice president at drug company Agenus, said, "The shortage of QS-21 has been an issue for a while." He added, "We saw it before COVID, and we made the hard decision that we had to change." 10The American company in Massachusetts stopped selling the natural version of QS-21 several years ago. It now centers on trying to grow it from quillay plant cells in a laboratory. Paragas said it is too soon to know when it will be ready. 11Botanical Solution, a California-based company, says it can already produce QS-21 from quillay seeds in the laboratory. The company adds that it aims to produce the substance in large quantities for drug companies. 12How many quillay trees are left? 13No one knows how many healthy quillay trees are left in Chile to meet the demand. Experts and industry officials believe that they will at some point need to switch to grow the evergreens on farms or in laboratories. 14Ricardo San Martin developed the pruning and extraction process that created the modern quillay industry. He said producers must immediately work toward making quillay products from younger, farm-grown trees. 15"My estimate four years ago was that we were heading towards the sustainability limit," he said. 16Quillay producers say the harvest can continue for now without destroying the supply of older trees. Novavax told Reuters that the company is working with suppliers to make sure "life-saving vaccines will be prioritized." 17Andres Gonzalez runs Desert King International which operates a quillay farm in Chile. It is Novavax's only supplier and the largest quillay exporter in the country. He said it produces enough quillay extract from older trees to make up to 4.4 billion vaccine treatments in 2022. 18With new supplies from privately owned forests, he said, the operation can meet demand for the rest of this year and part of the next. He admitted, however, that "at some point, these native forests will come to an end." 19Gustavo Cruz is a researcher at the University of Chile who worked with San Martin to industrialize the production of quillay. He said he generally trusts quillay producers to deal with supply and demand. He is more worried about other threats - especially a lack of water and fire. 20"The trees do eventually regrow," he said, "but there comes a time when they don't anymore." 21I'm Mario Ritter, Jr. 22Aislinn Laing and Allison Martell reported this story for Reuters. Hai Do adapted it for VOA Learning English. Mario Ritter, Jr. was the editor. 23____________________________________________________ 24Words in This Story 25extract -v. to remove something by pulling it out are using a process to get it out 26immune system -n. the system that protects the body from disease and infections 27prune -v. to cut off some of the branches of a tree so that it will grow better 28sustainability -n. able to be used without being completely used up or destroyed 29prioritized -adj. to be organized so that the most important thing is done or dealt with first 30eventually -adv. at some time later 31We want to hear from you. Write to us in the Comments section, and visit our Facebook page.