Read the following passage.
A. Every cell copies the genetic information in its DNA into messenger RNA, or mRNA. This molecule carries the instructions for a protein from the nucleus to the watery interior of the cell, where the protein-making machinery reads them. During the 1980s, scientists introduced efficient methods for making mRNA without growing cells, a process called in vitro transcription. Ideas for using mRNA in vaccines and treatments followed, but there were obstacles. Lab-made mRNA was unstable and hard to deliver, and it triggered inflammation. Early enthusiasm for using it in patients was therefore limited.
B. The Hungarian biochemist Katalin Karikó kept working on mRNA as a treatment. In the early 1990s, as an assistant professor at the University of Pennsylvania, she had trouble persuading research funders that her project mattered. There she began working with the immunologist Drew Weissman. They found that immune cells called dendritic cells treated lab-made mRNA as foreign, while mRNA from mammal cells did not cause the same reaction. The difference lay in the bases, the chemical letters of RNA, which are often modified in mammal cells. When modified bases were used, the inflammation almost disappeared. They published this in 2005, and in studies from 2008 and 2010 they showed that modified mRNA also greatly increased protein production.
C. By 2010, several companies were developing the method, and vaccines against the Zika virus and MERS were pursued. After the COVID-19 pandemic began in early 2020, two vaccines made from modified mRNA were developed at record speed. Each carried the code for the virus's surface protein, packed in lipid nanoparticles, tiny spheres that protect the mRNA. Inside the body, the mRNA directs cells to make that protein, and the immune system learns to treat it as foreign. Reported protection was around 95 per cent, and both vaccines had been approved by December 2020.
D. Researchers hope the same speed and flexibility will lead to vaccines against other infectious diseases and to cancer treatments. Clinical trials have tested mRNA treatment vaccines in people with several cancers, including pancreatic and colorectal cancer and melanoma. Some are personalized: each is designed from the molecular features of one patient's tumour, which takes 1 to 2 months after tissue samples are collected. In one early trial for head and neck cancer, 2 of the first 10 patients had all signs of their tumours disappear. Cancer researchers are testing both modified and unmodified mRNA in these experimental vaccines, and more research is needed to understand the relative advantages of each.
E. Not given in any of the above paragraphs.
Decide which paragraph, A to D, has the information given in each statement below. Select E if the information is not given in any of the paragraphs.