Emergence of evidence during disease outbreaks: lessons learnt from the Zika virus outbreak

Egli-Gany

Counotte

et al. 2020

Preprint

Self Cite

167

132

 Review question 1. Amongst people who become infected with SARS-CoV-2, what proportion does not experience symptoms at all during their infection? Summary estimate 15% (95% confidence interval, CI 10 to 22%, prediction interval 3 to 55%, 28 studies, random effect model. Version 1, summary estimate 29% (95% confidence interval 23 to 37%, 8 studies, fixed effect model);  Review question 2. Amongst people with SARS-CoV-2 infection who are asymptomatic when diagnosed, what proportion will develop symptoms later? Fifteen studies included, no change in result;  Review question 3. What proportion of SARS-CoV-2 transmission is accounted for by people who are either asymptomatic throughout infection, or pre-symptomatic? Four studies included, no change in result; : medRxiv preprint modelling studies, 40-60% of all SARS-CoV-2 infections are the result of transmission from presymptomatic individuals, with a smaller contribution from asymptomatic individuals. CONCLUSIONAn intermediate contribution of pre-symptomatic and asymptomatic infections to overall SARS-CoV-2 transmission means that combination prevention measures, with enhanced hand and respiratory hygiene, testing tracing and isolation strategies and social distancing, will continue to be needed.The findings of this living systematic review of publications early in the pandemic suggests that most SARS-CoV-2 infections are not asymptomatic throughout the course of infection. ABSTRACT Structured summary2 Provide a structured summary including, as applicable: background; objectives; data sources; study eligibility criteria, participants, and interventions; study appraisal and synthesis methods; results; limitations; conclusions and implications of key findings; systematic review registration number. 2-3

Section: Discussionmentioning

confidence: 99%

Asymptomatic SARS-CoV-2 infections: a living systematic review and meta-analysis

Egli-Gany

Counotte

et al. 2020

Preprint

Self Cite

167

132

“…In an analysis of 346 publications about Zika virus, we described the temporal sequence of publication of types of study to investigate causality. 9 Others have assessed the accumulation of study designs over time during the SARS-CoV-2 outbreak and concluded that early in the outbreak, simple observational studies and narrative reviews were most abundant. 10 Here, we proposed a hypothetical sequence: first, anecdotal observations are reported in case reports or case series.…”

Section: Introductionmentioning

confidence: 99%

Outbreaks of publications about emerging infectious diseases: the case of SARS-CoV-2 and Zika virus

Ipekci

Meili

et al. 2020

Preprint

Self Cite

SummaryBackgroundOutbreaks of infectious diseases generate outbreaks of scientific evidence. In 2016 epidemics of Zika virus emerged, largely in Latin America and the Caribbean. In 2020, a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused a pandemic of coronavirus disease 2019 (COVID-19). We compared patterns of scientific publications for the two infections over time.MethodsWe used living systematic review methods to search for and annotate publications according to study design. For Zika virus, a review team performed the tasks for publications in 2016. For SARS-CoV-2, a crowd of 25 volunteer scientists performed the tasks for publications up to May 24, 2020. We used descriptive statistics to categorise and compare study designs over time.FindingsWe found 2,286 publications about Zika virus in 2016 and 21,990 about SARS-CoV-2 up to 24 May 2020, of which we analysed a random sample of 5294. For both infections, there were more epidemiological than laboratory science studies. Amongst epidemiological studies for both infections, case reports, case series and cross-sectional studies emerged first, cohort and case-control studies were published later. Trials were the last to emerge. Mathematical modelling studies were more common in SARS-CoV-2 research. The number of preprints was much higher for SARS-CoV-2 than for Zika virus.InterpretationSimilarities in the overall pattern of publications might be generalizable, whereas differences are compatible with differences in the characteristics of a disease. Understanding how evidence accumulates during disease outbreaks helps us understand which types of public health questions we can answer and when.FundingMJC and HI are funded by the Swiss National Science Foundation (SNF grant number 176233). NL acknowledges funding from the European Union’s Horizon 2020 research and innovation programme - project EpiPose (grant agreement number 101003688). DBG is funded by the Swiss government excellence scholarship (2019.0774) and the Swiss School of Public Health Global P3HS.

Outbreaks of publications about emerging infectious diseases: the case of SARS-CoV-2 and Zika virus

Ipekci

Meili

et al. 2021

BMC Med Res Methodol

Self Cite

Background Outbreaks of infectious diseases generate outbreaks of scientific evidence. In 2016 epidemics of Zika virus emerged, and in 2020, a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused a pandemic of coronavirus disease 2019 (COVID-19). We compared patterns of scientific publications for the two infections to analyse the evolution of the evidence. Methods We annotated publications on Zika virus and SARS-CoV-2 that we collected using living evidence databases according to study design. We used descriptive statistics to categorise and compare study designs over time. Results We found 2286 publications about Zika virus in 2016 and 21,990 about SARS-CoV-2 up to 24 May 2020, of which we analysed a random sample of 5294 (24%). For both infections, there were more epidemiological than laboratory science studies. Amongst epidemiological studies for both infections, case reports, case series and cross-sectional studies emerged first, cohort and case-control studies were published later. Trials were the last to emerge. The number of preprints was much higher for SARS-CoV-2 than for Zika virus. Conclusions Similarities in the overall pattern of publications might be generalizable, whereas differences are compatible with differences in the characteristics of a disease. Understanding how evidence accumulates during disease outbreaks helps us understand which types of public health questions we can answer and when.