“…Non-financial constraints influencing health providers’ ability to deliver health services were considered in two thirds of included studies (n = 28) ( Adisasmito et al, 2015 ; Alistar et al, 2013 ; Bärnighausen et al, 2016 ; Barker et al, 2017 ; Bottcher et al, 2015 ; Bozzani et al, 2018 , 2020 ; Chen et al, 2019 ; Cruz-Aponte et al, 2011 ; Curran et al, 2016 ; Dalgiç et al, 2017 ; Ferrer et al, 2014 ; Krumkamp et al, 2011 ; Langley et al, 2014 ; Lin et al, 2011 ; Martin et al, 2011 ; McKay et al, 2018 ; Peak et al, 2020 ; Putthasri et al, 2009 ; Rudge et al, 2012 ; Salomon et al, 2006 ; Sébille and Valleron, 1997 ; Shattock et al, 2016 ; Stopard et al, 2019 ; Sumner et al, 2019 ; Verma et al, 2020 ; Zhang et al, 2020 ), while only two studies considered constraints to the demand for health services ( Hecht and Gandhi, 2008 ; Shim et al, 2011 ), and six articles considered both demand- and supply-side factors ( Anderson et al, 2014 , 2018 ; Hontelez et al, 2016 ; Marks et al, 2017 ; Martin et al, 2015a , b ; Stenberg et al, 2017 ). The models that exclusively include demand-side constraints both focus on vaccines: one study projected the public and private demand for an AIDS vaccine candidate under different vaccine characteristics (efficacy, duration of protection, price), performance (acceptability, compliance) and country-level profile scenarios (including political ability and motivation to implement HIV/AIDS prevention programmes) ( Hecht and Gandhi, 2008 ); the second study subdivided model compartments based on individual decisions to vaccinate against seasonal influenza, to assess the effects of vaccine hesitancy on coverage and to derive optimal vaccine allocation across age groups under a Nash (own interest) versus a utilitarian strategy (optimal for the population) ( Shim et al, 2011 ).…”