The first cases of reinfection are emerging in Hong Kong, the United States and Europe. There is growing evidence that immunity to the new coronavirus after infection may be short-lived. Following reports in Hong Kong that a man had contracted the virus for a second time just over four months, experts are now saying there is likely only a slim possibility of people being re-infected with COVID-19, but nobody knows for sure. They suggest immunity from the disease does not necessarily last long. So much for herd immunity, or full immunity. Concrete answers are vital in developing a vaccine, that is, if we ever get one.