Vaccine skeptics sometimes will raise doubts on the likelihood of a viable vaccine for SARS-CoV-2 becoming available late in 2020 or during the first half of 2021 based on the statement that we have “never had a successful vaccine for any coronavirus.” As you probably know, SARS-CoV-2 the virus that causes COVID-19 is one of several kinds of coronaviruses that can infect humans.
While it’s technically true that there has not yet been any vaccine approved for treatment for a coronavirus, that doesn’t mean there won’t be one soon. Given the motivation we have with almost a million deaths worldwide from COVID-19 as I am writing this and the billions of dollars firmly committed to dozens of projects worldwide, I fully expect that we will have multiple successful vaccines for SARS-CoV-2 within a year.
To put it simply, the main reason we don’t have vaccines for other coronaviruses is that they never killed anywhere near as many people as COVID-19 has. Some human coronaviruses cause the common cold (alone with rhinoviruses) but those are not a viable target for a vaccine because there are simply too many strains of them for any one vaccine to be effective against the majority of them. The diseases they cause are not particularly serious either. Nobody is going to spend billions to help fight diseases that at worst give you a running nose, not when there still are diseases like malaria around that kill vast numbers of people every year.
There are really only two other human coronaviruses that would have called for a vaccine, the one that causes Severe Acute Respiratory Syndrome (SARS) and the one that causes Middle East respiratory syndrome (MERS, also known as camel flu). The SARS epidemic in 2002-2004 killed about 800 people worldwide while MERS killed fewer than 900 over the past decade.
There was vaccine development for SARS (e.g. the Russian Sputnik V virus effort is an offshoot of that work), but when the SARS epidemic ended before the vaccine made it to market, funding for the safety trials still needed for final approval of the vaccine became unavailable. So it’s not that we couldn’t figure out how to make a vaccine that works against this close cousin of the latest coronavirus, we just didn’t have the vaccine approved by the time the virus stopped killing people.
The current vaccine projects use many different approaches, from using inactivated viruses to RNA vaccines to Viral vector vaccines. Some of these are tried and tested, others are pretty revolutionary new technology. Several of these projects are likely to be successful, which will bring us closer to herd immunity without having to let the forest fire of the pandemic rip through the entire population and the unacceptable death toll that would bring.