As scientists question whether the presence, or absence, of antibodies to the novel coronavirus can reliably determine immunity, some are looking to a different component of the immune system, known as T cells, for their role in protecting people in the pandemic.
Philippine President Rodrigo Duterte on Tuesday kept partial restrictions in the capital for another two weeks as he tries to contain the spread of the new coronavirus while reducing the pandemic's economic damage.
Scientists hope to get an answer on whether a vaccine works as early as this October. Developing a Covid-19 vaccine in record time will be tough. Producing enough to end the pandemic will be the biggest medical manufacturing feat in history.