补充：过去四周中，阳性中98.1%为无症状或轻症。只有四例病死，都不是全免。看来疫苗还是有效的

https://www.moh.gov.sg/news-highlights/details/update-on-local-covid-19-situation-(18-sep-2021)

Over the last 28 days, the percentage of local cases who were asymptomatic or had mild symptoms is 98.1%. 177 cases required oxygen supplementation, 18 had been in the ICU, and 4 died, of whom none was fully vaccinated2.