In Wuhan, a city of 11 million, both patients who believe they have been infected by the coronavirus and people with other medical problems are having difficulty seeing doctors: Shortages are common at such times, and quarantines only compound them. Residents are complaining on social media about inadequate care. Distrust of the health authorities is mounting.

And then, of course, overcrowding at hospitals, which mixes some presumably sick people with the healthy, increases the risks of transmission.

Some people may have tried to escape the stricken cities for less-infected areas. Others may be hiding from public health workers. A woman from Wuhan, apparently eager to stick to her travel plans for Lunar New Year, reportedly cheated a health check by taking fever-reducing drugs to bring her temperature down — and then admitted doing so on social media after she had arrived in France.

An integral failing of most quarantines is that some people, seeing the restrictions as overly strict and an imposition on their rights, will invariably try to bypass them. Their evasion, in turn, can endanger public health.