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Waiting for a coronavirus vaccine

The Covid-19 coronavirus has knocked our world off its axis. We won’t return to anything approaching normal — that is, life without social distancing, quarantines, masks, school closures and other control measures — until most of the world has been vaccinated against the virus. Everyone, therefore, has the same question on their mind: How fast will a vaccine be ready?

The history of vaccine development is not encouraging. “I’ve been working on vaccines for a long time,” says Barney Graham, deputy director of the Vaccine Research Center at the US National Institute of Allergy and Infectious Diseases. “I’ve never seen one take less than about 20 years.” It took 26 years to develop a vaccine for the human papilloma virus, for instance, and 25 years to secure one for rotavirus. And researchers have been trying for more than 50 years to find a vaccine against respiratory syncytial virus, one of the leading causes of infectious disease mortality in infants. Even after Graham’s group figured out a better approach in 2013, the vaccine is still only in the testing phase.

These are not normal times, however, and a vaccine for the Covid-19 virus, formally known as SARS-CoV-2, is the focus of unprecedented research efforts. Already, over 100 research groups have vaccine candidates under development, and a few are already being tested in people. In mid-May, the US government announced “Operation Warp Speed,” an initiative that aims to have a vaccine ready for general use by the end of 2020.

Almost all experts say that target is too optimistic, generally citing the spring of 2021 as a best-case scenario. But to hit even that later target, a lot of things have to break right, and a lot of logistic hurdles have to be cleared away. Here’s a look at some of the key issues in vaccine development.

What kinds of vaccines are there?

All vaccines aim for the same goal: exposing the body’s immune system to protein or carbohydrate fragments, or antigens, displayed by a virus or other pathogen. If all goes as planned, “memory cells” within the immune system remember this introduction. If the vaccinated person is later exposed to the actual virus, these cells enable the immune system to react quickly, suppressing the disease or reducing its severity.

Knowable Magazine is an independent journalistic endeavor from Annual Reviews.

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