Estimation of novel coronavirus (covid-19) reproduction number and case fatality rate: a systematic review and meta-analysis

Abstract

Understanding the transmission dynamics and the severity of the novel coronavirus disease 2019 (COVID-19) informs public health interventions, surveillance, and planning. Two important parameters, the basic reproduction number (R0) and case fatality rate (CFR) of COVID-19, help in this understanding process. The objective of this study was to estimate the R0 and CFR of COVID-19 and assess whether the parameters vary in different regions of the world. We carried out a systematic review to retrieve the published estimates of the R0 and the CFR in articles from international databases between 1st January and 31st August 2020. Random-effect models and Forest plots were implemented to evaluate the mean effect size of the R0 and the CFR. Furthermore, the R0 and CFR of the studies were quantified based on geographic location, the tests/thousand population, and the median population age of the countries where studies were conducted. The I2 statistic and the Cochran's Q test were applied to assess statistical heterogeneity among the selected studies. Forty-five studies involving R0 and thirty-four studies involving CFR were included. The pooled estimation of the R0 was 2.69 (95% CI: 2.40, 2.98), and that of the CFR was 2.67 (2.25, 3.13). The CFR in different regions of the world varied significantly, from 2.51 (2.12, 2.95) in Asia to 7.11 (6.38, 7.91) in Africa. We observed higher mean CFR values for the countries with lower tests (3.15 vs. 2.16) and greater median population age (3.13 vs. 2.27). However, the R0 did not vary significantly in different regions of the world. An R0 of 2.69 and CFR of 2.67 indicate the severity of the COVID-19. Although R0 and CFR may vary over time, space, and demographics, we recommend considering these figures in control and prevention measures.

SARS-CoV-2 epidemic after social and economic reopening in three US states reveals shifts in age structure and clinical characteristics

“…This is among the first studies to evaluate multiple simultaneous clinical data streams with an epidemic transmission model. The symptomatic case fatality ratios (sCFR) inferred for RI, PA, and MA (estimates range from 2.5% and 3.7%) are in the higher ranges of previously reported estimates [8][9][10][11][53][54][55], suggesting that the individuals infected during the spring wave and summer lull were more likely to progress to symptoms than the average person in the population. Again, this is consistent with the observation that children were the least exposed in the spring and summer months, and thus the exposed population was both more likely to progress to reportable symptoms and more likely to progress to severe clinical outcomes.…”

Finding the real COVID-19 case-fatality rates for SAARC countries

“…In agreement with previous studies [29,30], our estimated CFRs for selected countries were lower than most of the European countries' CFR. Several factors, such as temperature, the proportion of young people, genetic factors, can be responsible for this variation in CFR [12,14,[31][32][33]. Moreover, we found that CFR of the COVID-19 pandemic is less than SARS, MERS, Bird flu, and Ebola [34,35].…”

“…As a result, in the first 10 days since the imposition of test fees, there had been a decrease of 8,736 tests in total from the previous 10-day period. More tests can detect more asymptomatic or mild cases, which reduced the mortality rate [12,14]. However, as the decision had affected the poor citizen's ability or willingness of testing [18], the Bangladesh government decided to cut the test fees by almost half on 20 August [36].…”

“…Patients with critical health condition, populations with a higher proportion of older adults, inadequate resources and unorganized health care systems can have a higher CFR. [12,[37][38][39]. Second, we could not use country wise mean survival time of COVID-19 patients for the adjusted CFR estimation.…”

“…The Chinese Center for Disease Control and Prevention (China CDC) (2.3%) [8], Lim et al (approximately 1-2%) [9] and He et al (2.72% with 95% CI:1.29%□4.16%) [10] estimated the CFR of COVID-19. However, different geographical areas, such as East Asian and Central European countries, differ in the CFR of COVID-19 [11,12]. A study from April 2020 found that the CFR of COVID-19 in Italy was 10.8%, while in Germany, it was just 0.7% [13].…”