Could antibody testing hold clues for Covid-19 mystery?

Genetic sequencing has linked the Rydges Hotel worker to the same strain of virus found in a woman who stayed at the Auckland hotel between July 28 and 31 after returning from the United States. The Ministry of Health says there is no evidence the worker had any direct contact with the traveller. University of Auckland's Public health lecturer Simon Thornley explains how antibody (serology) testing might help solve the mystery of what is going on.