A Comparison of Case Fatality Risk of COVID-19 between Singapore and Japan

Abstract

The crude case fatality risk (CFR) for coronavirus disease (COVID-19) in Singapore is remarkably small. We aimed to estimate the unbiased CFR by age for Singapore and Japan and compare these estimates by calculating the standardized mortality ratio (SMR). Age-specific CFRs for COVID-19 were estimated in real time, adjusting for the delay from illness onset to death. The SMR in Japan was estimated by using the age distribution of the Singapore population. Among cases aged 60–69 years and 70–79 years, the age-specific CFRs in Singapore were estimated as 1.84% (95% confidence interval: 0.46–4.72%) and 5.57% (1.41–13.97%), respectively, and those in Japan as 5.52% (4.55–6.62%) and 15.49% (13.81–17.27%), respectively. The SMR of COVID-19 in Japan, when compared with Singapore as the baseline, was estimated to be 1.46 (1.09–2.96). The overall CFR for Singapore is lower than that for Japan. It is possible that the circulating variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Singapore causes a milder clinical course of COVID-19 infection compared with other strains. If infection with a low-virulence SARS-CoV-2 variant provides protection against infection by high-virulence strains, the existence of such a strain is encouraging news for the many countries struggling to suppress this virus.

Delay-Adjusted Age-Specific COVID-19 Case Fatality Rates in a High Testing Setting: South Korea, February 2020 to February 2021

“…Furthermore, this study found that both the delay-adjusted and crude CFRs showed substantial variations especially at the beginning of the pandemic in South Korea. Similar patterns have been observed in previous studies concerning delay-adjusted CFRs conducted in South Korea and other countries [ 11 , 25 , 31 , 32 ]. Thus, these results highlight that caution must be applied when interpreting CFRs, particularly earlier in the pandemic, even with adjustment for the delay between diagnosis and death.…”

“…This study aimed to estimate the risk of death among confirmed cases, taking into account ascertainment bias and right-censoring using established methods [ 20 , 25 ]. Given the importance of delay-adjusted CFR estimates according to age, this study aimed to provide real-time estimates of adjusted age-specific CFR during the COVID-19 pandemic, and to identify the most vulnerable segments of the population in South Korea, through February 2021.…”

COVID-19 patients age, comorbidity profiles and clinical presentation related to the SARS-CoV-2 UK-variant spread in the Southeast of France

“…Until today, reports of a relationship between SARS-CoV-2 genetic specificities among variants and clinical presentation are scarce. One variant with a deletion (∆382) in the open reading frame 8 have been associated to milder infections in Singapore 12 and may have play a role in the very low case fatality rate in this country 13 . Spike mutation D614G that probably occurs in China before its diffusion in Europe is associated with a decreased age of COVID-19 patients possibly due to an increased viral load in younger patients 14 .…”

Spread of the SARS-CoV-2 UK-variant in the South East of France: impact on COVID-19 patients’ age, comorbidity profiles and clinical presentation

“…Until today, reports of a relationship between SARS-CoV-2 genetic specificities among variants and clinical presentation are scarce. One variant with a deletion (∆382) in the open reading frame 8 have been associated to milder infections in Singapore [12] and may have play a role in the very low case fatality rate in this country [13]. Spike mutation D614G that probably occurs in China before its diffusion in Europe is associated with a decreased age of COVID-19 patients possibly due to an increased viral load in younger patients [14].…”