Vaccines usually take years to develop, but in the case of COVID-19 it took less than a year. Experts including Dr. Deepta Bhattacharya, UArizona immunobiologist and BIO5 member, say that part of the reason is the research has been going on for years. Even though the development of the vaccine was fast, it was slow enough to catch safety issues. It is possible that some people will still have adverse reactions to the vaccine. But Dr. Bhattacharya cautions the public not to take one or two cases of adverse reactions as a reason not to get vaccinated.