Among those deported to El Salvador on an April 7 flight from Houston, four tested positive for Covid-19 in a Salvadoran government quarantine facility. They insist that U.S. immigration authorities never tested them for the novel coronavirus. The United States has deported more than 1,700 Salvadorans during the pandemic, yet El Salvador’s immigration authorities have refused to divulge the number of Covid-19 cases among the deported population, according to the country’s Human Rights...