The United States has delivered two million doses of the antimalarial medicine hydroxychloroquine (HCQ) to Brazil to fight Covid-19, the White House said Sunday, though the drug has not been proven effective against the coronavirus. “HCQ will be used as a prophylactic to help defend Brazil’s nurses, doctors, and healthcare professionals against the virus. It will also be used as a therapeutic to treat Brazilians who become infected,” a statement said.It said the US would soon also send 1,000 ventilators to Brazil, the epicenter of South America’s outbreak with nearly 500,000 confirmed cases. “We are also announcing a joint United States-Brazilian research effort that will include randomized controlled clinical trials,” it added.The two countries will also conduct a joint research effort that will include “randomized controlled clinical trials”, the statement said, adding that the US would soon send 1,000 ventilators to Brazil. Brazil on Sunday said its nationwide tally of confirmed COVID-19 cases had reached 514,849 after 16,409 people tested positive in the latest 24-hour period, while the death toll neared 30,000.