Research in Brief: Vitamin A usage in different countries

We expect that reading the full report will be helpful for:

• Those who want a shallow overview of vitamin A supplementation delivery methods across 16 countries
• Those interested in an example of estimating a counterfactual

Context

In October 2023, GiveWell commissioned Rethink Priorities to conduct research on vitamin A supplementation (VAS): an intervention that involves providing vitamin A capsules to children aged 6 to 59 months every four to six months, as per WHO recommendations, to avoid vitamin A deficiency.

GiveWell has supported biannual VAS campaigns in a number of countries since 2017, through grants to Helen Keller International and Nutrition International. These campaigns are implemented alongside national “routine” methods of providing VAS, such as delivery of vitamin A at scheduled vaccination appointments, or delivery through outreach activities by community health workers.

In its cost-effectiveness analysis, GiveWell accounts for counterfactual access to VAS through routine services, as this reduces the benefit of vitamin A received through GiveWell-funded campaigns. At the time of writing, this “double treatment” parameter (see here) assumed 44% of children in Madagascar, and 25% of children in other countries, would access VAS in the counterfactual. The main aim of this project was to understand whether and how this parameter should be updated for countries currently in GiveWell’s model, and to produce estimates for additional countries of interest.

Research process

Over the course of six weeks, we conducted:

• A desk review of publicly available information for 16 countries
• A review of survey information shared with GiveWell by implementing partners
• Interviews with 13 experts, including individuals working at implementing organizations, in-country physicians, and an academic.

Based on this research, for each of the 16 countries our final report includes:

• A brief summary of how VAS is being delivered (and in some cases, how it has been delivered in the last ~10 years)
• An overview of available data that measures access to VAS, and to what extent it is useful to calculate the counterfactual
• A point estimate of counterfactual coverage, and an interval that represents an 80% confidence level. These estimates are available here.

Final report and key takeaways

One of the main takeaways from this work was that data on access to VAS — particularly coverage achieved through routine health services — is scarce. This leads to high levels of uncertainty, and as such, our ultimate recommendation to GiveWell is to use simplified point estimates for groups of countries, based on overlap of confidence intervals for country-specific estimates, and similarities in (counterfactual) VAS delivery mechanisms.

Our final recommendation can be found in this spreadsheet, and also in writing below.

• GW-supported countries: 15% baseline for all countries to reflect limited integration (e.g., only one platform) and limited outreach, except:
  • 35% in Burkina Faso, as rural areas are likely to be reached door to door
  • 45% in Kenya, Madagascar, and Nigeria, where recent evidence points to stronger VAS delivery mechanisms and higher access.
• In non-GW supported countries: 50% for all countries except:
  • 20% in Angola, where VAS delivery is almost certainly weaker
  • Unknown coverage for Togo (due to lack of available information)

These estimates do not take into account either a) the possibility that caregivers would increase their use of routine services in the absence of GiveWell-funded campaigns, or b) the possibility that other funders might deploy their existing budgets differently in the absence of GiveWell funding. Defining the counterfactual to account for either of these elements would lead to an increase in our estimates.

Following this report, given the scarcity of data, GiveWell intends to partner with Helen Keller International to integrate a question about VAS coverage from all sources into ongoing surveys. Results from these surveys will augment the information compiled in this report and may lead to updates to GiveWell’s cost-effectiveness model.

Additionally, we consider the question of whether access to VAS varies by age. Analysis of survey data suggests that access to VAS peaks between 9-23 months, and may decrease by 30%-40% for children aged 24-59 months. Our analysis also suggests that the reduction is smaller for campaigns than for routine delivery.

Read the report

To request the full report, please fill out this form.

Acknowledgments

This research is a project of Rethink Priorities — a think tank dedicated to informing decisions made by high-impact organizations and funders across various cause areas. The report was authored by Aisling Leow, and managed by Tom Hird and Melanie Basnak. Thanks to Adam Papineau for copyediting, and to Hannah Tookey for assistance with publishing the report online.

If you are interested in RP’s work, please visit our research database and subscribe to our newsletter.