It's been more than four years since the coming of Covid-19.  For several years I every Thursday reported on this pandemic.  I've noticed where I live at 15 Craigside, a seniors' community, that time and time again residents returned from trips away from Hawaii, and tended to test negative at first, but positive several days later.  My conclusion now is that they must have caught this virus while on the flight home.  There is one resident who never tested positive when she returned home, BUT, on three trips after the pandemic was cancelled, caught covid all three times while away. Two weeks ago, in my posting on  SHOULD YOU CONTINUE TO WORRY ABOUT COVID-19 WHEN YOU TRAVEL? , I quoted the  Mayo Clinic : Travel increases your chance of getting and spreading   COVID-19 . If you're unvaccinated, staying home is the best way to protect yourself and others from   COVID-19 . If you must travel and aren't vaccinated, talk with your health care provider and ask about any add