The sections mentioning COVID have been in place for over a year: http://web.archive.org/web/20210326031042/https://www.ready.gov/nuclear-explosion http://web.a

The sections mentioning COVID have been in place for over a year: http://web.archive.org/web/20210326031042/https://www.ready.gov/nuclear-explosion http://web.archive.org/web/20210326031042/https://www.ready.... i.e., from a time when almost no-one was vaccinated, and the strains of COVID going around were much deadlier. It's absolutely reasonable for the guidelines of that time to try to prevent fallout shelters crammed with thousands of people from all coming down with COVID simultaneously -- and particularly trying to protect aid workers.