Assessing the Impact of Vaccination on the Dynamics of COVID-19 in Africa: A Mathematical Modeling Study

Montcho, Yvette; Nalwanga, Robinah; Azokpota, Paustella; Doumatè, Jonas Têlé; Lokonon, Bruno Enagnon; Salako, Kolawolé Valère; Wolkewitz, Martin; Kakaï, Romain Lucas Glèlè

doi:10.3390/vaccines11040857

Cited by 6 publications

(4 citation statements)

References 51 publications

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“…In addition, the study shows that the combination of two categories of non-pharmaceutical control measures will reduce the cost of implementation of control measures and can curtail the epidemic. Furthermore, it is important to point out the role of vaccination in lowering the incidence of SARS-CoV-2 infections and COVID-19 hospital admission cases in Africa [49].…”

Section: Discussionmentioning

confidence: 99%

Analytical insights of the effects of Non-Pharmaceutical Interventions on SRAS-CoV-2 Dynamic with Application to West African Data

Traore,

Houenou,

Glèlè Kakaï

2023

Contemp. Math.

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The COVID-19 pandemic was caused by the rapid spread of a new coronavirus (SARS-CoV-2) worldwide. COVID-19 pandemic mitigation measures caused significant social and economic disruption, especially in regions with weak economic and fragile healthcare systems like West Africa. Therefore, accurate knowledge of the impact of these measures on its dynamics is important in decision-making. In this study, we formulated and used a deterministic compartmental model, considering two sub-classes of susceptible individuals (S1 and S2), where S1 is the population living around the epicenter of the epidemic and S2 is the population living far from the epicenter of the epidemic. The aim was to (i) theoretically assess the impact of measures reducing the transmission rate of the disease (ψ) on the epidemic dynamics and (ii) analyze the impact of measures reducing the probability of contact between infected and susceptible individuals (detection and isolation rates, θap, θs) on the epidemic dynamics. We determined the expressions of the basic and control reproduction numbers and studied the sensitivity and elasticity of the control reproduction number with respect to ψ, θap, θs, and heterogeneity factor, k(S1/S2). Application to the COVID-19 first-wave data from West Africa revealed that the basic reproduction number was 1.85. Moreover, the results indicated that a 50% reduction in the transmission rate of COVID-19 or the detection and isolation of 10% of infected individuals per day should help to reach the peak of the epidemic. Furthermore, a 100% increase in the heterogeneity factor induces a 16% increase in the control reproduction number when θap = 0.15 and a 14% increase in the control reproduction number when θap = 0.6. These conclusions could help design control measures to curtail future epidemics.

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Section: Discussionmentioning

confidence: 99%

Analytical insights of the effects of Non-Pharmaceutical Interventions on SRAS-CoV-2 Dynamic with Application to West African Data

Traore,

Houenou,

Glèlè Kakaï

2023

Contemp. Math.

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“…In defined clusters, such as households, cycles of virus transmission can be divided into primary and secondary events; primary transmission is the spread of the virus from the index case to contacts, and secondary transmission denotes spread from these contacts to additional contacts. Transmission of SARS-CoV-2 can be reduced by social distancing, mask wearing, and immunity derived from prior infections and/ or vaccinations (12)(13)(14)(15). Few studies have measured vaccine efficacy against transmission of SARS-CoV-2.…”

Section: Introductionmentioning

confidence: 99%

Mucosal immunization with ChAd-SARS-CoV-2-S prevents sequential transmission of SARS-CoV-2 to unvaccinated hamsters

Darling,

Harastani,

Joshi

et al. 2024

Sci. Adv.

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COVID-19 vaccines have successfully reduced severe disease and death after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Nonetheless, COVID-19 vaccines are variably effective in preventing transmission and symptomatic SARS-CoV-2 infection. Here, we evaluated the impact of mucosal or intramuscular vaccine immunization on airborne infection and transmission of SARS-CoV-2 in Syrian hamsters. Immunization of the primary contact hamsters with a mucosal chimpanzee adenoviral-vectored vaccine (ChAd-CoV-2-S), but not intramuscular messenger RNA (mRNA) vaccine, reduced infectious virus titers ~100-fold and 100,000-fold in the upper and lower respiratory tract of the primary contact hamster following SARS-CoV-2 exposure. This reduction in virus titer in the mucosal immunized contact animals was sufficient to eliminate subsequent transmission to vaccinated and unvaccinated hamsters. In contrast, sequential transmission occurred after systemic immunization with the mRNA vaccine. Thus, immunization with a mucosal COVID-19 vaccine protects against cycles of respiratory transmission of SARS-CoV-2 and can potentially limit the community spread of the virus.

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“…The R0 has increased to an estimated 5.1 to 5.7 for the Delta variant of SARS-CoV-2 18,19 and 9.5 to 13.3 for Omicron variants 20,21 . The R0 can be reduced by social distancing, mask wearing, and immunity derived from prior infections and/or vaccinations [22][23][24][25] .…”

Section: Introductionmentioning

confidence: 99%

Intranasal vaccination of Syrian Hamsters with ChAd-SARS-CoV-2-S disrupts airborne transmission cycles of SARS-CoV-2

Boon¹,

Harastani²,

Joshi³

et al. 2023

Preprint

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COVID-19 vaccines have successfully reduced severe disease and death after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Nonetheless, COVID-19 vaccines are variably effective in preventing symptomatic SARS-CoV-2 infection, and their role in inhibiting community viral transmission remains less well characterized. Here, we evaluated the impact of mucosal vaccination on primary and secondary airborne transmission of SARS-CoV-2 in a Syrian hamster pre-clinical model. Intranasal immunization of the primary contact hamsters with a chimpanzee adenoviral-vectored vaccine (ChAd-CoV-2-S) that is the predecessor of the currently used iNCOVACC® reduced infectious virus titers ~100-fold and 100,000-fold in the upper and lower respiratory tract of the primary contact hamster following SARS-CoV-2 exposure. This reduction in virus titer in the ChAd-CoV-2-S immunized contact animals was sufficient to eliminate secondary airborne SARS-CoV-2 transmission to both vaccinated and naïve hamsters. Thus, immunization with an intranasal COVID-19 vaccine disrupts transmission cycles of SARS-CoV-2 and can potentially limit community spread of the virus.

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Assessing the Impact of Vaccination on the Dynamics of COVID-19 in Africa: A Mathematical Modeling Study

Cited by 6 publications

References 51 publications

Analytical insights of the effects of Non-Pharmaceutical Interventions on SRAS-CoV-2 Dynamic with Application to West African Data

Analytical insights of the effects of Non-Pharmaceutical Interventions on SRAS-CoV-2 Dynamic with Application to West African Data

Mucosal immunization with ChAd-SARS-CoV-2-S prevents sequential transmission of SARS-CoV-2 to unvaccinated hamsters

Intranasal vaccination of Syrian Hamsters with ChAd-SARS-CoV-2-S disrupts airborne transmission cycles of SARS-CoV-2

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