Before the vitamin D link was so widely reported, I remember seeing a bunch of comments online (including HN) from people saying things along the lines of "We've been self-isolating at home since January, only bought things online, and STILL got sick!"
I'm not a professional and this is just me spouting ideas, but I wonder if this is one reason why America is so hard hit compared to Asia. Americans generally commute by car, stay in a massive building complex all day for work, and go home and stay inside. In Asia, a huge proportion of people commute by foot, train (which involves walking to the station), or scooter. Then they walk to a grocery store or restaurant to get some food. I wonder if those minutes of continuous sun exposure add up and lighten the severity of it.
I'm not a professional and this is just me spouting ideas, but I wonder if this is one reason why America is so hard hit compared to Asia. Americans generally commute by car, stay in a massive building complex all day for work, and go home and stay inside. In Asia, a huge proportion of people commute by foot, train (which involves walking to the station), or scooter. Then they walk to a grocery store or restaurant to get some food. I wonder if those minutes of continuous sun exposure add up and lighten the severity of it.