Several students who tested positive for COVID-19 linked to private tutor at tuition centre: MOH Toggle share menu Advertisement Several students who tested positive for COVID-19 linked to private tutor at tuition centre: MOH Teachers will no longer be allowed to wear face shields in place of surgical masks in the classroom, as authorities announced tighter COVID-19 measures amid a rise in community cases. Deborah Wong reports. 2 related media assets (image or videos) available. Click to see the gallery. 14 May 2021 11:15PM) Share this content Bookmark SINGAPORE: Several students who have tested positive for COVID-19 are linked to a private tutor at a tuition centre, said the Ministry of Health’s (MOH) director of medical services Kenneth Mak on Friday (May 14).