Epidemiological impact and cost-effectiveness analysis of COVID-19 vaccination in Kenya
Abstract
Background
Few studies have assessed the benefits of COVID-19 vaccines in settings where most of the population had been exposed to SARS-CoV-2 infection.
Methods
We conducted a cost-effectiveness analysis of COVID-19 vaccine in Kenya from a societal perspective over a 1.5-year time frame. An age-structured transmission model assumed at least 80% of the population to have prior natural immunity when an immune escape variant was introduced. We examine the effect of slow (18 months) or rapid (6 months) vaccine roll-out with vaccine coverage of 30%, 50% or 70% of the adult (> 18 years) population prioritizing roll-out in over 50-year olds (80% uptake in all scenarios). Cost data were obtained from primary analyses. We assumed vaccine procurement at $7 per dose and vaccine delivery costs of $3.90-$6.11 per dose. The cost-effectiveness threshold was USD 919.
Findings
Slow roll-out at 30% coverage largely targets over 50-year-olds and resulted in 54% fewer deaths (8,132(7,914 to 8,373)) than no vaccination and was cost-saving (ICER=US$-1,343 (-1,345 to - 1,341) per DALY averted). Increasing coverage to 50% and 70%, further reduced deaths by 12% (810 (757 to 872) and 5% (282 (251 to 317) but was not cost-effective, using Kenya’s cost-effectiveness threshold ($ 919.11). Rapid roll-out with 30% coverage averted 63% more deaths and was more cost-saving (ICER=$-1,607 (-1,609 to -1,604) per DALY averted) compared to slow roll-out at the same coverage level, but 50% and 70% coverage scenarios were not cost-effective.
Interpretation
With prior exposure partially protecting much of the Kenyan population, vaccination of young adults may no longer be cost-effective.
KEY QUESTIONS
What is already known?
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The COVID-19 pandemic has led to a substantial number of cases and deaths in low-and middle-income countries.
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COVID-19 vaccines are considered the main strategy of curtailing the pandemic. However, many African nations are still at the early phase of vaccination.
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Evidence on the cost-effectiveness of COVID-19 vaccines are useful in estimating value for money and illustrate opportunity costs. However, there is a need to balance these economic outcomes against the potential impact of vaccination.
What are the new findings?
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In Kenya, a targeted vaccination strategy that prioritizes those of an older age and is deployed at a rapid rollout speed achieves greater marginal health impacts and is better value for money.
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Given the existing high-level population protection to COVID-19 due to prior exposure, vaccination of younger adults is less cost-effective in Kenya.
What do the new findings imply?
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Rapid deployment of vaccines during a pandemic averts more cases, hospitalisations, and deaths and is more cost-effective.
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Against a context of constrained fiscal space for health, it is likely more prudent for Kenya to target those at severe risk of disease and possibly other vulnerable populations rather than to the whole population.
Article activity feed
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Ciaran Kohli-Lynch
Review 2: "Epidemiological Impact and Cost-Effectiveness Analysis of COVID-19 Vaccination in Kenya"
This study assesses the benefits of COVID-19 vaccines where most have already been exposed to SARS-CoV-2. Reviewers agree that their transmission modeling approach and sensitivity analyses were reliable, though further research in other counties would validate their findings.
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Mark Jit
Review 1: "Epidemiological Impact and Cost-Effectiveness Analysis of COVID-19 Vaccination in Kenya"
This study assesses the benefits of COVID-19 vaccines where most have already been exposed to SARS-CoV-2. Reviewers agree that their transmission modeling approach and sensitivity analyses were reliable, though further research in other counties would validate their findings.
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Mark Jit, Ciaran Kohli-Lynch
Reviews of: "Epidemiological Impact and Cost-Effectiveness Analysis of COVID-19 Vaccination in Kenya"
Reviewers: M Jit (London School of Hygiene and Tropical Medicine) | 📗📗📗📗◻️ • C Kohli-Lynch (Northwestern) | 📗📗📗📗◻️
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SciScore for 10.1101/2022.04.21.22274150: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
NIH rigor criteria are not applicable to paper type.Table 2: Resources
Software and Algorithms Sentences Resources Cost estimates: The cost estimates used in this study were derived using a hybrid method that involved both an ingredients approach (bottom-up) and a top-down approach. Costsuggested: (COST, RRID:SCR_014098)Results from OddPub: Thank you for sharing your code and data.
Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:This underlines the limitations of using a narrow health system perspective that ignores broader societal costs of health system interventions. This is even more so for a vaccine deployed in a pandemic that has …
SciScore for 10.1101/2022.04.21.22274150: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
NIH rigor criteria are not applicable to paper type.Table 2: Resources
Software and Algorithms Sentences Resources Cost estimates: The cost estimates used in this study were derived using a hybrid method that involved both an ingredients approach (bottom-up) and a top-down approach. Costsuggested: (COST, RRID:SCR_014098)Results from OddPub: Thank you for sharing your code and data.
Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:This underlines the limitations of using a narrow health system perspective that ignores broader societal costs of health system interventions. This is even more so for a vaccine deployed in a pandemic that has substantial socio-economic impacts, in addition to health impacts. These findings mirror cost-effectiveness studies of COVID-19 vaccination done in Turkey and Pakistan that found that although COVID-19 vaccination strategies were cost-effective from a health system’s perspective, they were cost-saving from a societal perspective.[39,41] This is in line with arguments from studies that estimate the public health value and impact of vaccination, which argue the need to broaden the perspectives for cost-effectiveness analysis of vaccines, as their impact is far-reaching, especially in the context of a pandemic.[42–44] These findings have implications for COVID-19 vaccination policy in Kenya and other low-and middle-income countries (LMIC) settings with comparable demographic and COVID-19 epidemiological profiles. First, not unexpectedly, where an outbreak is imminent efforts to rapidly deploy the vaccine not only avert more cases, hospitalization, and deaths, but are also more cost-effective. By extension, had Kenya been able to deploy vaccines more rapidly, benefits would have been greater. Second, COVID-19 vaccination is likely to offer the best value for money when targeted to older age groups and possibly other vulnerable groups (such as those with risk increasing com...
Results from TrialIdentifier: No clinical trial numbers were referenced.
Results from Barzooka: We did not find any issues relating to the usage of bar graphs.
Results from JetFighter: We did not find any issues relating to colormaps.
Results from rtransparent:- Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
- Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
- No protocol registration statement was detected.
Results from scite Reference Check: We found no unreliable references.
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