In this paper, we present a Caputo fractional-order COVID-19 model that incorporates nucleic acid testing and individual protective awareness to capture memory effects and the interaction of non-pharmaceutical interventions. We proved the existence, non-negativity, and boundedness of solutions and derived the basic reproduction number $R_{0}$ using the next-generation matrix method. Stability analysis showed that the disease-free equilibrium is globally asymptotically stable when $R_{0} < 1$, and the endemic equilibrium is globally asymptotically stable when $R_{0}>1$. Numerical simulations using the PECE scheme of the Adams–Bashforth–Moulton method validate the theoretical results and demonstrate the role of the fractional-order parameter $\alpha$ in capturing transmission memory. Model parameters were estimated using a hybrid genetic algorithm-least squares approach calibrated with Malaysian COVID-19 data. The proposed model outperformed both integer-order and simplified fractional SEIR models in replicating real-world dynamics. Sensitivity and uncertainty analyses identified protective awareness and testing intensity as key factors in mitigating epidemic severity. We also formulated an optimal control problem, applying Pontryagin's maximum principle to derive six intervention strategies. Cost-effectiveness analysis showed that combined interventions are superior to single strategies, proving effective and economically viable under Malaysia's healthcare constraints.
Citation: Rui Hu, Elayaraja Aruchunan, Muhamad Hifzhudin Noor Aziz, Cheng Cheng, Benchawan Wiwatanapataphee. Dynamic analysis and optimal control of a fractional-order epidemic model with nucleic acid detection and individual protective awareness: A Malaysian case study[J]. AIMS Mathematics, 2025, 10(7): 16157-16199. doi: 10.3934/math.2025724
In this paper, we present a Caputo fractional-order COVID-19 model that incorporates nucleic acid testing and individual protective awareness to capture memory effects and the interaction of non-pharmaceutical interventions. We proved the existence, non-negativity, and boundedness of solutions and derived the basic reproduction number $R_{0}$ using the next-generation matrix method. Stability analysis showed that the disease-free equilibrium is globally asymptotically stable when $R_{0} < 1$, and the endemic equilibrium is globally asymptotically stable when $R_{0}>1$. Numerical simulations using the PECE scheme of the Adams–Bashforth–Moulton method validate the theoretical results and demonstrate the role of the fractional-order parameter $\alpha$ in capturing transmission memory. Model parameters were estimated using a hybrid genetic algorithm-least squares approach calibrated with Malaysian COVID-19 data. The proposed model outperformed both integer-order and simplified fractional SEIR models in replicating real-world dynamics. Sensitivity and uncertainty analyses identified protective awareness and testing intensity as key factors in mitigating epidemic severity. We also formulated an optimal control problem, applying Pontryagin's maximum principle to derive six intervention strategies. Cost-effectiveness analysis showed that combined interventions are superior to single strategies, proving effective and economically viable under Malaysia's healthcare constraints.
| [1] |
I. Chakraborty, P. Maity, COVID-19 outbreak: Migration, effects on society, global environment and prevention, Sci. Total Environ., 728 (2020), 138882. https://doi.org/10.1016/j.scitotenv.2020.138882 doi: 10.1016/j.scitotenv.2020.138882
|
| [2] |
N. Shrestha, M. Y. Shad, O. Ulvi, M. H. Khan, A. Karamehic-Muratovic, U. S. D. Nguyen, et al., The impact of COVID-19 on globalization, One Health, 11 (2020), 100180. https://doi.org/10.1016/j.onehlt.2020.100180 doi: 10.1016/j.onehlt.2020.100180
|
| [3] |
S. Naseer, S. Khalid, S. Parveen, K. Abbass, H. Song, M. V. Achim, COVID-19 outbreak: Impact on global economy, Front. Public Health, 10 (2023), 1009393. https://doi.org/10.3389/fpubh.2022.1009393 doi: 10.3389/fpubh.2022.1009393
|
| [4] |
A. U. M. Shah, S. N. A. Safri, R. Thevadas, N. K. Noordin, A. A. Rahman, Z. Sekawi, et al., COVID-19 outbreak in Malaysia: Actions taken by the Malaysian government, Int. J. Infect. Dis., 97 (2020), 108–116. https://doi.org/10.1016/j.ijid.2020.05.093 doi: 10.1016/j.ijid.2020.05.093
|
| [5] |
W. O. Kermack, A. G. McKendrick, A contribution to the mathematical theory of epidemics, Proc. Roy. Soc. Lond. A, 115 (1927), 700–721. https://doi.org/10.1098/rspa.1927.0118 doi: 10.1098/rspa.1927.0118
|
| [6] |
I. Cooper, A. Mondal, C. G. Antonopoulos, A SIR model assumption for the spread of COVID-19 in different communities, Chaos Soliton. Fract., 139 (2020), 110057. https://doi.org/10.1016/j.chaos.2020.110057 doi: 10.1016/j.chaos.2020.110057
|
| [7] |
Y. C. Chen, P. E. Lu, C. S. Chang, T. H. Liu, A time-dependent SIR model for COVID-19 with undetectable infected persons, IEEE T. Netw. Sci. Eng., 7 (2020), 3279–3294. https://doi.org/10.1109/TNSE.2020.3024723 doi: 10.1109/TNSE.2020.3024723
|
| [8] |
S. He, Y. Peng, K. Sun, SEIR modeling of the COVID-19 and its dynamics, Nonlinear Dyn., 101 (2020), 1667–1680. https://doi.org/10.1007/s11071-020-05743-y doi: 10.1007/s11071-020-05743-y
|
| [9] |
S. Annas, M. I. Pratama, M. Rifandi, W. Sanusi, S. Side, Stability analysis and numerical simulation of SEIR model for pandemic COVID-19 spread in Indonesia, Chaos Soliton. Fract., 139 (2020), 110072. https://doi.org/10.1016/j.chaos.2020.110072 doi: 10.1016/j.chaos.2020.110072
|
| [10] |
I. Korolev, Identification and estimation of the SEIRD epidemic model for COVID-19, J. Econometrics, 220 (2021), 63–85. https://doi.org/10.1016/j.jeconom.2020.07.038 doi: 10.1016/j.jeconom.2020.07.038
|
| [11] |
S. S. Musa, S. Qureshi, S. Zhao, A. Yusuf, U. T. Mustapha, D. He, Mathematical modeling of COVID-19 epidemic with effect of awareness programs, Infect. Dis. Model., 6 (2021), 448–460. https://doi.org/10.1016/j.idm.2021.01.012 doi: 10.1016/j.idm.2021.01.012
|
| [12] |
Y. Chen, Y. R. Gel, M. V. Marathe, H. V. Poor, A simplicial epidemic model for COVID-19 spread analysis, Proc. Natl. Acad. Sci., 121 (2024), e2313171120. https://doi.org/10.1073/pnas.2313171120 doi: 10.1073/pnas.2313171120
|
| [13] |
C. Cheng, E. Aruchunan, M. H. N. Aziz, Leveraging dynamics informed neural networks for predictive modeling of COVID-19 spread: A hybrid SEIRV-DNNs approach, Sci. Rep., 15 (2025), 2043. https://doi.org/10.1038/s41598-025-85440-1 doi: 10.1038/s41598-025-85440-1
|
| [14] |
Y. Chen, F. Liu, Q. Yu, T. Li, Review of fractional epidemic models, Appl. Math. Model., 97 (2021), 281–307. https://doi.org/10.1016/j.apm.2021.03.044 doi: 10.1016/j.apm.2021.03.044
|
| [15] |
P. A. Naik, M. Farman, A. Zehra, K. S. Nisar, E. Hincal, Analysis and modeling with fractal-fractional operator for an epidemic model with reference to COVID-19 modeling, Part. Differ. Equ. Appl. Math., 10 (2024), 100663. https://doi.org/10.1016/j.padiff.2024.100663 doi: 10.1016/j.padiff.2024.100663
|
| [16] |
R. Zarin, A. Khan, A. Yusuf, S. Abdel-Khalek, M. Inc, Analysis of fractional COVID-19 epidemic model under Caputo operator, Math. Method. Appl. Sci., 46 (2023), 7944–7964. https://doi.org/10.1002/mma.7294 doi: 10.1002/mma.7294
|
| [17] |
A. Abbes, A. Ouannas, N. Shawagfeh, H. Jahanshahi, The fractional-order discrete COVID-19 pandemic model: Stability and chaos, Nonlinear Dyn., 111 (2023), 965–983. https://doi.org/10.1007/s11071-022-07766-z doi: 10.1007/s11071-022-07766-z
|
| [18] |
H. D. S. Adam, M. Althubyani, S. M. Mirgani, S. Saber, An application of Newton's interpolation polynomials to the zoonotic disease transmission between humans and baboons system based on a time-fractal fractional derivative with a power-law kernel, AIP Adv., 15 (2025), 045217. https://doi.org/10.1063/5.0253869 doi: 10.1063/5.0253869
|
| [19] |
M. Althubyani, S. Saber, Hyers-Ulam stability of fractal-fractional computer virus models with the Atangana-Baleanu operator, Fractal Fract., 9 (2025), 158. https://doi.org/10.3390/fractalfract9030158 doi: 10.3390/fractalfract9030158
|
| [20] |
S. Saber, E. Solouma, R. A. Alharb, A. Alalyani, Chaos in fractional-order glucose-insulin models with variable derivatives: Insights from the Laplace–Adomian decomposition method and generalized Euler techniques, Fractal Fract., 9 (2025), 149. https://doi.org/10.3390/fractalfract9030149 doi: 10.3390/fractalfract9030149
|
| [21] |
A. Turab, R. Shafqat, S. Muhammad, M. Shuaib, M. F. Khan, M. Kamal, Predictive modeling of hepatitis B viral dynamics: A Caputo derivative-based approach using artificial neural networks, Sci. Rep., 14 (2024), 21853. https://doi.org/10.1038/s41598-024-70788-7 doi: 10.1038/s41598-024-70788-7
|
| [22] |
A. Alsulami, R. A. Alharb, T. M. Albogami, N. H. Eljaneid, H. D. Adam, S. F. Saber, Controlled chaos of a fractal-fractional Newton-Leipnik system, Thermal Sci., 28 (2024), 5153–5160. https://doi.org/10.2298/TSCI2406153A doi: 10.2298/TSCI2406153A
|
| [23] |
M. Alhazmi, F. M. Dawalbait, A. Aljohani, K. O. Taha, H. D. Adam, S. Saber, Numerical approximation method and chaos for a chaotic system in sense of Caputo-Fabrizio operator, Thermal Sci., 28 (2024), 5161–5168. https://doi.org/10.2298/TSCI2406161A doi: 10.2298/TSCI2406161A
|
| [24] |
A. Turab, H. Hilmi, J. L. G. Guirao, S. Jalil, N. Chorfi, P. O. Mohammed, The Rishi transform method for solving multi-high order fractional differential equations with constant coefficients, AIMS Math., 9 (2024), 3798–3809. https://doi.org/10.3934/math.2024187 doi: 10.3934/math.2024187
|
| [25] |
D. Denu, S. Kermausuor, Analysis of a fractional-order COVID-19 epidemic model with lockdown, Vaccines, 10 (2022), 1773. https://doi.org/10.3390/vaccines10111773 doi: 10.3390/vaccines10111773
|
| [26] |
M. A. A. Oud, A. Ali, H. Alrabaiah, S. Ullah, M. A. Khan, S. Islam, A fractional order mathematical model for COVID-19 dynamics with quarantine, isolation, and environmental viral load, Adv. Differ. Equ., 2021 (2021), 1–19. https://doi.org/10.1186/s13662-021-03265-4 doi: 10.1186/s13662-021-03265-4
|
| [27] |
S. Paul, A. Mahata, S. Mukherjee, P. C. Mali, B. Roy, Fractional order SEIQRD epidemic model of COVID-19: A case study of Italy, PLoS One, 18 (2023), e0278880. https://doi.org/10.1371/journal.pone.0278880 doi: 10.1371/journal.pone.0278880
|
| [28] |
E. C. de Oliveira, J. A. T. Machado, A review of definitions for fractional derivatives and integral, Math. Probl. Eng., 2014 (2014), 1–7. https://doi.org/10.1155/2014/238459 doi: 10.1155/2014/238459
|
| [29] |
G. S. Teodoro, J. T. Machado, E. C. de Oliveira, A review of definitions of fractional derivatives and other operators, J. Comput. Phys., 388 (2019), 195–208. https://doi.org/10.1016/j.jcp.2019.03.008 doi: 10.1016/j.jcp.2019.03.008
|
| [30] |
R. Agarwal, P. Airan, R. P. Agarwal, Exploring the landscape of fractional-order models in epidemiology: A comparative simulation study, Axioms, 13 (2024), 545. https://doi.org/10.3390/axioms13080545 doi: 10.3390/axioms13080545
|
| [31] |
S. Rosa, D. F. M. Torres, Numerical fractional optimal control of respiratory syncytial virus infection in Octave/Matlab, Mathematics, 11 (2023), 1511. https://doi.org/10.3390/math11061511 doi: 10.3390/math11061511
|
| [32] |
Y. Bo, C. Guo, C. Lin, Y. Zeng, H. B. Li, Y. Zhang, et al., Effectiveness of non-pharmaceutical interventions on COVID-19 transmission in 190 countries from 23 January to 13 April 2020, Int. J. Infect. Dis., 102 (2021), 247–253. https://doi.org/10.1016/j.ijid.2020.10.066 doi: 10.1016/j.ijid.2020.10.066
|
| [33] |
A. Mendez-Brito, C. El Bcheraoui, F. Pozo-Martin, Systematic review of empirical studies comparing the effectiveness of non-pharmaceutical interventions against COVID-19, J. Infect., 83 (2021), 281–293. https://doi.org/10.1016/j.jinf.2021.06.018 doi: 10.1016/j.jinf.2021.06.018
|
| [34] |
A. Lison, N. Banholzer, M. Sharma, S. Mindermann, H. J. T. Unwin, S. Mishra, et al., Effectiveness assessment of non-pharmaceutical interventions: Lessons learned from the COVID-19 pandemic, Lancet Public Health, 8 (2023), e311–e317. https://doi.org/10.1016/S2468-2667(23)00046-4 doi: 10.1016/S2468-2667(23)00046-4
|
| [35] |
B. A. Baba, B. Bilgehan, Optimal control of a fractional order model for the COVID-19 pandemic, Chaos Soliton. Fract., 144 (2021), 110678. https://doi.org/10.1016/j.chaos.2021.110678 doi: 10.1016/j.chaos.2021.110678
|
| [36] |
T. Trisilowati, I. Darti, R. R. Musafir, M. Rayungsari, A. Suryanto, Dynamics of a fractional-order COVID-19 epidemic model with quarantine and standard incidence rate, Axioms, 12 (2023), 591. https://doi.org/10.3390/axioms12060591 doi: 10.3390/axioms12060591
|
| [37] |
K. Diethelm, Monotonicity of functions and sign changes of their Caputo derivatives, Fract. Calc. Appl. Anal., 19 (2016), 561–566. https://doi.org/10.1515/fca-2016-0029 doi: 10.1515/fca-2016-0029
|
| [38] |
S. Majee, S. Jana, D. K. Das, T. K. Kar, Global dynamics of a fractional-order HFMD model incorporating optimal treatment and stochastic stability, Chaos Soliton. Fract., 161 (2022), 112291. https://doi.org/10.1016/j.chaos.2022.112291 doi: 10.1016/j.chaos.2022.112291
|
| [39] |
J. Danane, Z. Hammouch, K. Allali, S. Rashid, J. Singh, A fractional-order model of coronavirus disease 2019 (COVID-19) with governmental action and individual reaction, Math. Method. Appl. Sci., 46 (2023), 8275–8288. https://doi.org/10.1002/mma.7759 doi: 10.1002/mma.7759
|
| [40] |
D. D. Hailemichael, K. E. Geremew, P. R. Koya, Effect of vaccination and culling on the dynamics of rabies transmission from stray dogs to domestic dogs, Hind J. Appl. Math., 2022 (2022), 2769494. https://doi.org/10.1155/2022/2769494 doi: 10.1155/2022/2769494
|
| [41] | O. Diekmann, J. A. P. Heesterbeek, Mathematical epidemiology of infectious diseases: Model building, analysis and integration, New York: Wiley, 2000. |
| [42] |
E. Ahmed, A. M. A. El-Sayed, H. A. El-Saka, On some Routh–Hurwitz conditions for fractional order differential equations and their applications in Lorenz, Rössler, Chua and Chen systems, Phys. Lett. A, 358 (2006), 1–4. https://doi.org/10.1016/j.physleta.2006.04.087 doi: 10.1016/j.physleta.2006.04.087
|
| [43] |
G. Z. Lin, L. L. Hao, Stability of a SEIQR epidemic model with infectious incubation period and infectious period, J. Southwest China Normal Univ. (Nat. Sci. Ed.), 45 (2020), 1–4. https://doi.org/10.13718/j.cnki.xsxb.2020.03.001 doi: 10.13718/j.cnki.xsxb.2020.03.001
|
| [44] | J. P. La Salle, The stability of dynamical systems, Philadelphia: Society for Industrial and Applied Mathematics, 1976. https://doi.org/10.1137/1.9781611970432 |
| [45] |
N. Águila-Camacho, M. A. Duarte-Mermoud, J. A. Gallegos, Lyapunov functions for fractional order systems, Commun. Nonlinear Sci. Numer. Simul., 19 (2014), 2951–2957. https://doi.org/10.1016/j.cnsns.2014.01.022 doi: 10.1016/j.cnsns.2014.01.022
|
| [46] |
C. Vargas-De-León, Volterra-type Lyapunov functions for fractional-order epidemic systems, Commun. Nonlinear Sci. Numer. Simul., 24 (2015), 75–85. https://doi.org/10.1016/j.cnsns.2014.12.013 doi: 10.1016/j.cnsns.2014.12.013
|
| [47] |
J. Li, X. Tan, W. Wu, X. Zou, A Caputo fractional derivative dynamic model of hepatitis E with optimal control based on particle swarm optimization, AIP Adv., 14 (2024), 045125. https://doi.org/10.1063/5.0193463 doi: 10.1063/5.0193463
|
| [48] |
I. M. Elbaz, M. A. Sohaly, H. El-Metwally, Random dynamics of an SIV epidemic model, Commun. Nonlinear Sci. Numer. Simul., 131 (2024), 107779. https://doi.org/10.1016/j.cnsns.2023.107779 doi: 10.1016/j.cnsns.2023.107779
|
| [49] |
R. Garrappa, Numerical solution of fractional differential equations: A survey and a software tutorial, Mathematics, 6 (2018), 16. https://doi.org/10.3390/math6020016 doi: 10.3390/math6020016
|
| [50] |
R. Garrappa, On linear stability of predictor-corrector algorithms for fractional differential equations, Int. J. Comput. Math., 87 (2010), 2281–2290. https://doi.org/10.1080/00207160802624331 doi: 10.1080/00207160802624331
|
| [51] | Ministry of Health Malaysia, COVID-19 public data, 2024. Available from: https://github.com/MoH-Malaysia/covid19-public. |
| [52] |
N. Sene, Analysis of the fractional SEIR epidemic model with Caputo derivative via resolvent operators and numerical scheme, Discrete Cont. Dyn.-S, 18 (2025), 1316–1330. https://doi.org/10.3934/dcdss.2024149 doi: 10.3934/dcdss.2024149
|
| [53] | L. S. Pontryagin, Mathematical theory of optimal processes, Routledge, 2018. http://dx.doi.org/10.1201/9780203749319 |
| [54] |
S. I. Oke, M. B. Matadi, S. S. Xulu, Cost-effectiveness analysis of optimal control strategies for breast cancer treatment with ketogenic diet, Far East J. Appl. Math., 109 (2018), 303–342. http://dx.doi.org/10.17654/MS109020303 doi: 10.17654/MS109020303
|
| [55] | Ministry of Health Malaysia, MOH Spends RM18,000 Per Critically Sick COVID-19 Patient, CodeBlue, 2020. Available from: https://codeblue.galencentre.org/2020/07/moh-spends-rm18000-per-critically-sick-covid-19-patient/. |