OBJECTIVES: Valid measurement of the SARS-CoV-2 incubation period is needed for case definitions and for adapting appropriate isolation measures but is challenging in an emergency context . Our objective was to systematically review recent literature of reported estimates of the distribution of incubation period of SARS-CoV-2 with the aim of describing the distribution and its variability and dispersion through meta-analysis .
METHODS: A systematic review search was carried out up to January 10 , 2021 of all identified references available reporting the SARS-CoV-2 incubation period . Individual mean and standard deviation were used to produce the pooled estimate . Sources of heterogeneity were explored by age, gender and study design using a meta-regression .
RESULTS: In total , 99 studies were eligible for analysis in our meta-analysis . The pooled estimate of the mean incubation period across the studies was 6.38 days , 95% CI [5.79; 6.97].
CONCLUSION: The mean incubation period will help for identification of time of exposure, but determinants of its variations/range might be explored for potential links with clinical outcome or pathogenic steps at early time of infection . A real time meta-analysis, called the InCoVid Lyon, is proposed on an appropriate website following this initial analysis.