Concern is mounting over the long-term effects of Covid-19 for more than 600,000 New Zealanders who have contracted the virus since the pandemic began, RNZ reports. New research suggests a quarter of people who have been infected will continue to have symptoms for a month. 10% of patients will feel unwell three months on. Immunologist and University of Auckland senior lecturer Anna Brooks is part of a team of international researchers investigating long Covid, but she said there was still much unknown.