21 March 2022. Faced with the increase of Covid-19 re-infections, Vietnam Deputy Minister of Health said that medical experts and staff had met to prepare for a quick study to people in the high-risk groups to value their immune response. Based on the valuation, the sector will recommend the fourth dose of vaccine for high-risk people and people with underlying diseases. Former deputy director of the Ho Chi Minh City Biotechnology Center also suggested people still have to strictly adhere to 5K principles.https://www.sggpnews.org.vn/health/increased-recurrence-rate-of-covid19-people-advised-not-to-relax-vigilance-98014.html