Everyone is spooked about the  COVID-19 subvariant BA.5,  for it today accounts for 65% of infections in the USA, and is the most contagious of them all.   The latest data shows that both the BA.4 and BA.5 are about as transmissible as the measles. This means that, like the measles, these subvariants will infect 90% of people who are not immune through close contact with an infected person. Actually, the common cold is #1 in contagiousness, followed by conjunctivitis ( pink eye ), viral gastroenteritis ( like norovirus ) and strep throat. The  Delta variant is 60% more contagious than the Alpha , which itself was 50% more contagious than the original COVID-19 virus.  Delta is more contagious than the flu or chicken pox, and on par with the measles.   If Delta, BA.4 and BA.5 are equal to the measles, why have the latter subvariants replaced Delta?  One answer is that the BA.4 and BA.5 subvariants can bypass the immune system of those vaccinated or previously infected.   In any case, tho