Health impact and cost-effectiveness of COVID-19 vaccination in Sindh Province, Pakistan
AbstractBackgroundMultiple COVID-19 vaccines appear to be safe and efficacious, but only high-income countries have the resources to procure sufficient vaccine doses for most of their eligible populations. The World Health Organization has published guidelines for vaccine prioritisation, but most vaccine impact projections have focused on high-income countries, and few incorporate economic considerations. To address this evidence gap, we projected the health and economic impact of different vaccination scenarios in Sindh province, Pakistan (population: 48 million).MethodsWe fitted a compartmental transmission model to COVID-19 cases and deaths in Sindh from 30 April to 15 September 2020 using varying assumptions about the timing of the first case and the duration of infection-induced immunity. We then projected cases and deaths over 10 years under different vaccine scenarios. Finally, we combined these projections with a detailed economic model to estimate incremental costs (from healthcare and partial societal perspectives), disability adjusted life years (DALYs), and cost-effectiveness for each scenario.FindingsA one-year vaccination campaign using an infection-blocking vaccine at $3/dose with 70% efficacy and 2.5 year duration of protection is projected to avert around 0.93 (95% Credible Interval: 0.91, 1.0) million cases, 7.3 (95% CrI: 7.2, 7.4) thousand deaths and 85.1 (95% CrI: 84.6, 86.8) thousand DALYs, and be net cost saving from the health system perspective. However, paying a high price for vaccination ($10/dose) may not be cost-effective. Vaccinating the older (65+) population first would prevent slightly more deaths and a similar number of cases as vaccinating everyone aged 15+ at the same time, at similar cost-effectiveness.InterpretationCOVID-19 vaccination can have a considerable health impact, and is likely to be cost-effective if more optimistic vaccine scenarios apply. Preventing severe disease is an important contributor to this impact, but the advantage of focusing initially on older, high-risk populations may be smaller in generally younger populations where many people have already been infected, typical of many low- and -middle income countries, as long as vaccination gives good protection against infection as well as disease.FundingBill & Melinda Gates Foundation, World Health Organization, Medical Research Council, UK Research and Innovation, Health Data Research UKResearch in contextEvidence before this studySearching PubMed, medRxiv, and econLit using the search term (“coronavirus” OR “covid” OR “ncov”) AND (“vaccination” OR “immunisation”) AND (“model” OR “cost” OR “economic”) for full text articles published in any language between 1 January 2020 and 20 January 2021, returned 29 (PubMed), 1,167 (medRxiv) and 0 (econLit) studies, of which 20 were relevant to our study. Four of these studies exclusively focused on low- or middle-income countries (India, China, Mexico), while 3 multi-country analyses also included low- or middle-income settings. The majority of studies overall conclude that targeting COVID-19 vaccination to older age groups is the preferred strategy to minimise mortality, particularly when vaccine supplies are constrained, while other age- or occupational risk groups should be priorities when vaccine availability increases or when other policy objectives are pursued. Only three studies considered economic outcomes, all of them comparing the costs of vaccination to the costs of other non-pharmaceutical interventions and concluding that both are necessary to reduce infections and maximise economic benefit.Added value of this studyOur study provides the first combined epidemiological and economic analysis of COVID-19 vaccination based on real-world disease and programmatic information in a low- or middle-income country. Our findings suggest that vaccination in this setting is highly cost-effective, and even cost saving, as long as the vaccine is reasonably priced and efficacy is high. Unlike studies in high-income settings, we also found that vaccination programmes targeting all adults may have similar impact to those initially targeted at older populations, likely reflecting the higher previous infection rates and different demography in these settings.Implications of all the available evidenceLMICs and international bodies providing guidance for LMICs need to consider evidence specific to these settings when making recommendations about COVID-19 vaccination. Further data and model-based analyses in such settings are urgently needed in order to ensure that vaccination decisions are appropriate to their contexts.
