Fig. 4From: Assessing the impact of COVID-19 interventions on influenza-like illness in Beijing and Hong Kong: an observational and modeling studyObserved and predicted weekly ILI counts from 2011 to 2021 in Beijing, estimated by GAM models using: a Eq. 6 and ILI data in 2011–2019, b Eq. 6 and ILI data in 2011–2017, and c Eq. 7 and ILI data in 2011–2019, respectively. The estimated ILI in 2020–2021 were predicted under a counterfactual scenario of no COVID-19 interventions. The purple-shaded parts indicate the period of the COVID-19 pandemic and its related NPIs. ILI influenza-like illness, GAM generalized additive model, COVID-19 coronavirus disease 2019, NPIs non-pharmaceutical interventionsBack to article page