Study on Effects of COVID-19 Infection on Vaccinated Persons

Mr Gan Thiam Poh asked the Minister for Health (a) in respect of fully vaccinated individuals who have tested positive for COVID-19 locally, what are their average recovery times; (b) whether the Ministry has conducted any study of the duration of COVID-19 infection in these individuals; and (c) if so, whether such study also confirms that the risk of transmission between fully vaccinated individuals is lower as compared to unvaccinated individuals.

Fully vaccinated patients recover faster and are infectious for a shorter period. Based on a recent study of local cases by the National Centre for Infectious Diseases (NCID), viral levels in vaccinated patients can decline to undetectable or non-infectious levels within 10 days after illness onset. This takes around 15 days, on average, for unvaccinated patients. However, during the infectious period, vaccinated and non-vaccinated patients are equally likely to transmit to others.