I’m not a doctor, but common sense tells us that there has to be a reason that the coronavirus spread more in New York City than in other highly populated areas like the large California cities. I believe the reason is that in NYC, because of the heavy reliance on mass transit and the high concentration of high-rise buildings, there has been much more concentrated surface contact, which spread the virus much more rapidly. There are bottlenecks at the doorways to high rise buildings, with thousands of people passing through the same door each day, touching the doors, and then touching their faces, their food, and each other.
The coronavirus apparently lives on surfaces much longer than other more common viruses, like the common flu or cold. I believe this bottleneck characteristic has contributed significantly to the spread of the virus in NYC. This also explains why we have not seen the same spread in places like San Francisco and LA, for example.
The implications of this are several. First, NYC, with a little effort, could address the bottlenecks by having people wear gloves when they pass through doorways and ride the subway. They could have people cleaning the surfaces – doorways, escalator railings, etc., frequently – say every 5 minutes, and have people avoid touching their faces especially just after passing through a bottleneck area. With knowledge of this risk, people should use hand sanitizer, or wash their hands, immediately after touching any common surface, like a door handle, door frame, escalator or stairwell railing.
The other key implication for places not like NYC is that we don’t have the same bottlenecks, so we don’t have the same level of risk for potential spread. This means that, in California and lots of other places, with reasonable, responsible behavior, there is no reason we can’t start reopening businesses immediately. For those cities with high-rise buildings, the same precautions should be put in place and followed. Masks and gloves should still be used, where possible, and hand sanitizer and hand washing protocols should still be followed. With that stated, we should be focusing on getting businesses reopened as quickly as possible, given these reasonable measures, so the economy can start to rebound, and life can get back to normal as quickly as possible.