The thrust of this revolution – the capacity to create an infinitesimal part of an already minute virus, without handling a virus specimen at all – can seem godlike. But the next two stages – testing vaccines in humans and then manufacturing them for wide use – remain mortally slow. This is especially so because these newest types of vaccines – DNA or RNA vaccines – have never yet been licensed for use on humans. Outside a lab, they are completely unproven. With Covid-19, both contagion and vaccine are so new that there’s no telling what human trials will reveal, or how long they will take. Every scientist, policymaker and researcher I spoke to said that we’ll be lucky to have a vaccine for use within 12-18 months.

If a DNA or RNA vaccine against Covid-19 is ever approved, it will be a watershed moment – not just because it will bear out the promise of this technology, but also because the technology will fortify us against future pandemics. Over the past few years, epidemiologists, risk analysts and policymakers have made concerted efforts to sharpen research and rethink the industrial model of vaccine production, all in preparation for the hypothetical disaster they call Disease X: any unknown disease that springs suddenly into our species and races ruinously through it. Covid-19 is the first Disease X to arise since the term was invented, but it won’t be the last. The climate is warming, we’re hacking down forests, our population is expanding and our skills at waging biological warfare are improving. The odds that we’ll keep encountering more and more Disease Xs are increasing. We will need all the vaccines we can make.