A 33 year-old Hong Kong man who was infected with the Wuhan coronavirus in April, and made a full recovery, was reinfected more than four months later after a trip to Spain via the UK, according to researchers. A research team from the University of Hong Kong calls this “the world’s first documentation” of a patient who recovered from the Wuhan virus becoming reinfected. There have been anecdotal reports of reinfection, but they were not confirmed.
On its face, this news seems discouraging for a number of obvious reasons. It suggests that a vaccine, if and when developed, might be much less effective than many people are assuming. It also suggests that “herd immunity” might not realistically be achievable.
However, there are reasons not to be discouraged. Apparently, the Hong Kong man had no symptoms the second time around. So maybe his immune system protected him from real disease, although not reinfection.
Indeed, Akiko Iwasaki, an immunology expert at Yale University, called this “a textbook example of how immunity should work.” She also said that “vaccines can provoke a much higher level of immunity [than infection] that can potentially block reinfection, or at least shut it down to a noncontagious level.”
Of course, just because the Hong Kong man had no symptoms the second time around doesn’t mean the next reinfected person won’t have serious symptoms. As with so much else about this virus, we just don’t know much about the likelihood and likely severity of reinfections.