There are lots of factors that affect the spread of a virus. The virus does not spread well in hot and humid climates. The virus does not spread well in areas where a large portion of the population does not travel everyday to urban centers 60 miles away or more to work. A lot of these countries do not have millions of world travels bringing the disease in to the country over and over again. And maybe most importantly these are countries with avg life expectancies 10 or 20 years shorter than the US life expectancy. Not alot of Botswanans are likely to die of covid at 70 because they are all dead of AIDS by 60. This virus spreads really well in highly densly populated cities in cold weather winters. And it kills old people, which we have a lot of and some other places dont.