How the Pandemic Will End?

Ed Yong, writing for The Atlantic: The world is experienced at making flu vaccines and does so every year. But there are no existing vaccines for coronaviruses -- until now, these viruses seemed to cause diseases that were mild or rare -- so researchers must start from scratch. The first steps have been impressively quick. Last Monday, a possible vaccine created by Moderna and the National Institutes of Health went into early clinical testing. That marks a 63-day gap between scientists sequencing the virus's genes for the first time and doctors injecting a vaccine candidate into a person's arm. "It's overwhelmingly the world record," Fauci said. But it's also the fastest step among many subsequent slow ones. The initial trial will simply tell researchers if the vaccine seems safe, and if it can actually mobilize the immune system. Researchers will then need to check that it actually prevents infection from SARS-CoV-2. They'll need to do animal tests and large-scale trials to ensure that the vaccine doesn't cause severe side effects. They'll need to work out what dose is required, how many shots people need, if the vaccine works in elderly people, and if it requires other chemicals to boost its effectiveness.

"Even if it works, they don't have an easy way to manufacture it at a massive scale," said Seth Berkley of Gavi. That's because Moderna is using a new approach to vaccination. Existing vaccines work by providing the body with inactivated or fragmented viruses, allowing the immune system to prep its defenses ahead of time. By contrast, Moderna's vaccine comprises a sliver of SARS-CoV-2's genetic material -- its RNA. The idea is that the body can use this sliver to build its own viral fragments, which would then form the basis of the immune system's preparations. This approach works in animals, but is unproven in humans. By contrast, French scientists are trying to modify the existing measles vaccine using fragments of the new coronavirus. "The advantage of that is that if we needed hundreds of doses tomorrow, a lot of plants in the world know how to do it," Berkley said. No matter which strategy is faster, Berkley and others estimate that it will take 12 to 18 months to develop a proven vaccine, and then longer still to make it, ship it, and inject it into people's arms.

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