RIO DE JANEIRO, BRAZIL - Despite half a year running from Covid-19, the science working to explain the disease is far from reaching a consensus. One of the most controversial issues is the pathogen's transmission routes. For the World Health Organization (W.H.O.), the main infection route is the virus-laden drops that escape with coughing, sneezing, etc., and end up in someone else's mouth, eyes, or nose. Hence the social distancing, the masks, and the handwashing.
However, for months, experts in airborne infections have been urging the W.H.O. to accept that viruses are also . . .