It's not clear how COVID-19 outbreaks at three Salt Lake City child day care centers began, but a new report finds that 12 infected youngsters enrolled at two of the facilities easily passed SARS-CoV-2 to at least 12 family members. In one case, an infected child with no symptoms of COVID-19 transmitted the illness to their mother, who became so sick she needed to be hospitalized. The tale of these day care-linked clusters illustrate how efficient children are as vectors for COVID-19 infection -- and what steps can be taken to minimize the risk, experts say.