Kolkata: Johnson & Johnson is preparing the ground for the entry of a vaccine against COVID-19 and is expanding its manufacturing capacity to supply more than one billion doses through 2021 in a not-for-profit project aimed at the common person, says its top scientist.The US-based pharma giant, which has already advanced its schedule of starting human trials of its candidate vaccine to the second half of July from September, is working on the twin fronts of expanding existing manufacturing capacity and establishing new units, Chief Scientific Officer Paul Stoffels told PTI."We plan to begin production at risk and are committed to bringing an affordable vaccine to the public on a not-for-profit basis for emergency pandemic use.