“…Our objective here is to present and analyse an SIR or SI like ODE model for non-smokers, tobacco smokers, and those who smoke e-cigarettes, incorporating peer pressure in the switch from tobacco to e-cigarette smoking. We note that differential equation models have been used extensively in modelling social problems and related issues, including the spread of infections; see, eg, Bissell,7,8 Bissell et al, 9 Buonomo et al, 10 Caiado, 11 Ciarcia et al, 12 Giacobbe and Mulone, 13 Giacobbe et al, 14 Gonzalez et al, 15 Guo et al, 16 Hethcote et al, 17 Huo and Song, 18 Huo and Wang, 19 Jung et al, 20 Mulone and Straughan, 21,22 Mulone et al, 23 Mushanyu et al, 24 Nyabadza et al, 25 Pomeroy, 26 Sharomi and Gumel, 27 Srivastava and Günerhan, 28 Straughan, 29 Takeuchi et al, 30 Usaini et al, 31 Walters, 32 Walters and Kendal, 33 Wang, 34 Wang et al, 35 Wang and Mulone, 36 Wang and Zhao, 37,38 Wang and Zou, 39 and Zhou et al 40 In particular, SIR models and ramifications thereof, such as those involving conformity bias (Walters, 32 Walters and Kendal, 33 and Bissell 8 ), incorporating external information (Buonomo et al 10 and Giacobbe et al 14 ), and allowing for multi-patch models (Wang and Mulone 36 ), have been employed in...…”