How The mRNA Vaccines Were Made: Halting Progress and Happy Accidents

MERS, like all coronaviruses, had a curious feature reminiscent of the shape-shifting proteins on H.I.V.: squirmy spikes on its surface that latch onto human cells. They had thwarted all efforts to make a vaccine. The MERS spike was especially fearsome, so much so that the scientists struggled to reproduce and isolate it in the lab. It was large, covered in a thick bush of sugars and highly unstable.

“It was pretty much a nightmare,” Dr. McLellan said.

Making matters more difficult, Dr. Graham had failed to secure samples from anyone infected with MERS in the Middle East.

After years of Western scientists parachuting into lower-income countries for studies that excluded local researchers, especially during the AIDS crisis, governments had “become very protective of their samples,” Dr. Graham said.

When a young Lebanese-American flu researcher in his lab, Hadi Yassine, recovered from an illness after a trip to Mecca, Dr. Graham thought he might have been infected with MERS. But it turned out to be a cold virus known as HKU1.

It was then that Dr. Graham had his insight: The world’s most boring coronaviruses may hold critical lessons about the most dangerous ones.

Like other coronaviruses, HKU1 had the dreaded spike — and, with some modifications, it held steadier than the one on the MERS virus. Within a few years, the team — which now included Andrew Ward, an expert, at the Scripps Research Institute, in freezing proteins to hold them still under an electron microscope — had published intricate images of the HKU1 spike in Nature. It was the first time scientists had visualized a human coronavirus spike protein in the initial form it took before latching onto cells.

“You can consider it luck,” Dr. Yassine said recently of his long-ago cold, “or you can consider it a blessing.”

Article source: https://www.nytimes.com/2022/01/15/health/mrna-vaccine.html