ALEXIS AKWAGYIRAM  WHEN Loveth Metiboba's baby had diarrhoea, she worried that taking him to a clinic near her home in Nigeria's capital, Abuja, might expose them both to the coronavirus. "The idea of going to the clinic was very scary," said Metiboba, a researcher for a charity. Instead, the clinic, run by Nigerian health technology firm eHealth Africa, sent her a web browser link to hold a video chat with a doctor who diagnosed her son with a mild illness and prescribed medicine to avoid dehydration. Across the globe, the COVID-19 pandemic has accelerated changes in the way medicine is…