There are dozens of Covid-19 coronavirus vaccines being tested right now, but no guarantee any of them will succeed. | Mladen Antonov/AFP via Getty Images
We need to plan for many different Covid-19 vaccine scenarios. These four factors will influence the outcome.
Without a vaccine or treatment, the world has been forced to adopt severe tactics to slow the spread of Covid-19: social distancing, shutdowns, closures, and cancellations. As states in the US begin to reopen, it’s clear there is still much hardship to come — for those laid off, for businesses forced to implement costly new health measures, for those still at risk of infection.
But the global race to develop a Covid-19 vaccine to shield people from the infection is now well underway, and gaining ground by the week. There are now more than 90 vaccines under development from governments, nonprofits,