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Sightsavers — Deworming in Nigeria and Cameroon (February 2022)

Note: This page summarizes the rationale behind a GiveWell-recommended grant to Sightsavers. Sightsavers staff reviewed this page prior to publication.


In February 2022, GiveWell made a $7.8 million grant to Sightsavers. The grant was funded by donations to the Maximum Impact Fund between October and December 2021. Sightsavers expects to use $4.3 million of this grant to continue supporting deworming in Cameroon and $3.5 million in seven states in Nigeria. Sightsavers' deworming program is one of GiveWell's top charities.

We recommended this grant because we believe that the work that the grant will support will be cost-effective. Deworming is among the most cost-effective programs we know of, in certain locations. The need for deworming appears to be high in the areas where Sightsavers expects to use this grant. We have followed Sightsavers' work on deworming since 2015 and, more recently, in these specific locations, and we believe that Sightsavers is well-positioned to support this work.

Published: March 2022

Planned activities and budget

This grant will extend support for ongoing programs for April 2023 to March 2025.1 Sightsavers expects to use $4.3 million to support deworming in Cameroon (West, North, Far North, East, Adamaoua, Littoral, and South regions)2 and $3.5 million in Nigeria (Kebbi, Kogi, Kwara, Sokoto, Benue, Yobe, and Taraba states).3

See here for a breakdown of how Sightsavers has spent past funding for deworming programs across spending categories.

The case for the grant

  • We estimate that this grant will meet our bar for cost-effectiveness. More below.
  • We believe that it is unlikely that another funder will cover these costs. More below.
  • Sightsavers has a track record of supporting successful deworming programs. More in our review of Sightsavers' deworming program.


Based on our cost-effectiveness analysis of the program, we believe it is in the range of cost-effectiveness of programs we expect to direct funding to, as of January 2022. Our estimate is that the Sightsavers-supported deworming program in Cameroon is 13x as cost-effective as GiveDirectly's program,4 which provides unconditional cash transfers to poor households in low-income countries, and 29x GiveDirectly's program in the seven states in Nigeria.5 At the time we recommended this grant, we were primarily looking to recommend grants that we estimated were more than 8x as cost-effective as GiveDirectly, and were willing to consider recommending a limited amount of funding to grants that were between 5x and 8x as cost-effective as GiveDirectly.

Note that our cost-effectiveness analyses are simplified models that do not take into account a number of factors. There are limitations to this kind of cost-effectiveness analysis, and we believe that cost-effectiveness estimates such as these should not be taken literally due to the significant uncertainty around them. We provide these estimates (a) for comparative purposes to other grants we have made or considered making, and (b) because working on them helps us ensure that we are thinking through as many of the relevant issues as possible.

Our cost-effectiveness analysis for this grant is based on the same structure as our model for other deworming grants. While investigating this grant, we updated parameters within that model to use inputs specific to this funding gap. Below, we highlight parameters that vary for different funding gaps and have a substantial impact on our headline cost-effectiveness figures:

  • Worm burden: For every deworming grant, we ask the potential grantee to provide data on the prevalence and/or intensity of infections with each species of schistosomiasis and soil-transmitted helminths in the locations where they would support deworming. We prefer to use data on the prevalence of moderate-intensity infections and of heavy-intensity infections for each species. When this isn't available, we use average intensity of infection or prevalence of any infection. We then apply an adjustment to our cost-effectiveness estimates of deworming programs to account for differences between the prevalence and intensity of worm infections in the geographies targeted by our deworming grantees and the prevalence and intensity of worm infections among the population studied in Miguel and Kremer 2004 the randomized controlled trial (RCT) on which we base our estimate of deworming's impact on consumption. We have used region-level estimates for Cameroon and state-level estimates for Nigeria.6 We did not update our worm burden adjustments specifically for this grant.
  • Cost per child dewormed: As we've funded these programs in the past, our estimates are based on the results achieved by the programs in 2018-2019 in Cameroon and 2017-2019 in Nigeria.7

We estimate that deworming in each of the seven states in Nigeria supported by this grant is above 8x GiveDirectly's program.8 We estimate that the cost-effectiveness of deworming in six out of seven regions in Cameroon supported by this grant is above 8x.9 More information on the one region, Littoral, that is below 8x in our model, is available below.

Funding landscape

For this grant, we largely relied on what we had learned about recent changes in the funding landscape for deworming while investigating another recent grant to Sightsavers, discussed here. The UK government, a major funder of neglected tropical disease programs, including deworming, ended its support for these programs in 2021.10 A group of foundations is working to help fill part of the gap left by the UK government's withdrawal.11 Based on what we know now, we believe there is a fairly low likelihood that these funders would fund deworming across Nigeria and Cameroon.

Risks and reservations

  • In December 2021, Sightsavers told us the availability of one of the drugs that is often donated to deworming programs, praziquantel, may be lower going forward. According to Sightsavers, the World Health Organization, which manages the praziquantel donations, has begun asking countries to request only enough praziquantel to target sub-districts, rather than districts, that meet the prevalence threshold for requiring deworming.12 This will generally mean that countries qualify for less donated praziquantel than they did before. We expect this to mean that the programs supported by this and future grants will become more cost-effective (because they target areas with higher worm burden on average) and for a given program to spend less per year, though the effects may be muted by lower efficiencies of a smaller scale program. The implications for this grant in particular are not yet clear to us, but may mean that the grant is larger than it needs to be for the April 2023-March 2025 periods. We are comfortable with this risk because we expect that Sightsavers will use any extra funding to continue the programs in later years.
  • We estimate that cost-effectiveness in one region in Cameroon, Littoral, which accounts for 28% of the Cameroon budget in this grant, is 1.4x.13 Though Littoral does not, by this estimate, meet our bar for cost-effectiveness,14 we decided to include Littoral in the grant. This is because neighboring regions have high worm burdens,15 which might indicate that the data we've seen from Littoral does not reflect reality and understates the need for deworming treatment. Additional work would be needed to increase our confidence in the worm burden adjustment we use for Littoral, and given the relatively small amount of funding this represents and the fact that the remainder of the grant will support work above 8x cash, we decided not to prioritize that work at this time.

Plans for follow up

Sightsavers provides annual updates for all GiveWell-supported deworming programs. These updates include narrative progress reports, coverage survey reports, and annual spending reports.16 Sightsavers also shares informal updates by email and in conversation.

Our process

Our process for this grant relied heavily on (a) our prior work on modeling the cost-effectiveness of Sightsavers' deworming program, and (b) our following Sightsavers' work on the deworming programs we have funded since 2016,17 including frequent discussions with Sightsavers and reports on coverage achieved, funding spent, and troubleshooting issues that Sightsavers encountered. For this particular grant, we revisited worm burden data reports from Nigeria to assess it for representativeness of the populations targeted by deworming programs and concluded that we did not need to update our worm burden model. Over the past six months, we have also spoken with representatives of several funders who work on neglected tropical disease programs (a category that includes deworming programs) about the funding landscape for deworming broadly.18


Document Source
GiveWell, "Sightsavers — Support for Deworming in Kaduna, Zamfara, Niger, Kano, Adamawa, and Katsina in 2021-2023 (October 2021)" Source
GiveWell, "Sightsavers' Deworming Program," 2021 Source
GiveWell, "Why we can’t take expected value estimates literally (even when they’re unbiased)," 2011 Source
GiveWell, “Our updated top charities for giving season 2016,” 2016. Source
GiveWell, 2022 cost-effectiveness analysis version 3 Source
GiveWell, Room for more funding analysis for Sightsavers' deworming program, 2021 (public) Source
GiveWell, Sightsavers Cameroon and Nigeria cost-effectiveness [December 2021] Source
GiveWell, Sightsavers' cost per child dewormed analysis, 2020 (public) Source
GiveWell, Summary of 2020 Worm Burden Model (public) Source
GiveWell, Worm burden adjustment: moderate infection equivalent model (public), 2020 Source
Miguel and Kremer 2004 Source (archive)
Sightsavers proposal for Nigeria ex-Ascend states, 2021 Source
Sightsavers prevalence and treatment data for Cameroon, 2021 Source
Sightsavers, Taraba State, Nigeria budget and treatment numbers, 2021 Source
  • 1.

    Information about these ongoing programs is available in our Sightsavers review: “In 2017, Sightsavers used GiveWell-directed funds to add deworming MDAs to the integrated NTD programs that it already supported in the Democratic Republic of the Congo (DRC), Guinea, Guinea-Bissau, and four Nigerian states, to support a deworming impact survey in Cameroon, and to initiate an integrated NTD program in Benue State, Nigeria. In 2018 and 2019, Sightsavers used GiveWell-directed funds to continue these programs and to expand its work to Cameroon and two additional states in Nigeria. In 2020, Sightsavers continued its support to these programs, though program implementation was delayed in Cameroon and Nigeria and deferred to 2021 in DRC, Guinea, and Guinea-Bissau, primarily because of the COVID-19 pandemic.” GiveWell, “Sightsavers' Deworming Program,” 2021, What do they do?

  • 2.

    See here.

  • 3.

    Budget (in millions) for Kebbi: $0.5 Kogi: $0.3 Kwara: $0.5 Sokoto: $0.5 Benue: $0.7 Yobe: $0.5 GiveWell, Room for more funding analysis for Sightsavers' deworming program, 2021 (public). Budget in millions for Taraba: $290,777 + $209,650 = $0.5 million. Taraba wasn't included in the room-for-more funding analysis, and the budget is available here. Total for Nigeria = 3.5 million.

  • 4.

    See GiveWell, Sightsavers Cameroon and Nigeria cost-effectiveness [December 2021], “Cameroon” sheet.

  • 5.

    See GiveWell, Sightsavers Cameroon and Nigeria cost-effectiveness [December 2021], “Nigeria” sheet.

  • 6.

    Worm burden adjustments are here in our cost-effectiveness analysis. This is the supplemental sheet from which these estimates are pulled.

  • 7.

    See our calculations of the cost per child dewormed in this spreadsheet: GiveWell, Sightsavers' cost per child dewormed analysis, 2020 (public). In the “Costs by country and year” sheet, Cameroon has costs for 2018-2019 and Nigeria for 2017-2019. Note: In Cameroon, In 2017-2019, separate costs in Cameroon were incurred to conduct a research project, rather than to deliver treatments.

  • 8.

    See here for the cost-effectiveness of each of the seven Nigeria states.

  • 9.

    Cost-effectiveness is estimated to be above 8x in the West, North, Far North, East, Adamaoua, and South regions of Cameroon. See here.

  • 10.

    “The sudden termination of the funded Ascend contract at the beginning of the final project year will impact the control of SCH and STH if new funding cannot be found.” Sightsavers proposal for Nigeria ex-Ascend states, 2021, pg. 2.

  • 11.

    “Children's Investment Fund Foundation (CIFF), the Bill & Melinda Gates Foundation (BMGF), and ELMA Philanthropies have pledged funding to support some of the programs that were previously funded by ASCEND, including some deworming programs and some programs treating other NTDs” GiveWell, “Sightsavers — Support for Deworming in Kaduna, Zamfara, Niger, Kano, Adamawa, and Katsina in 2021-2023 (October 2021)".

  • 12.

    We learned about this during a call with Sightsavers on December 6, 2021 (unpublished).

  • 13.

    Sightsavers Cameroon and Nigeria cost-effectiveness [December 2021] Note: we are estimating the distribution of the budget in Cameroon based on the percentage of total school-aged children (SAC) treated per region, so the percentage of the budget covered by this grant can be seen in the “% of total SAC (2023-2025) treated per region” column.

  • 14.

    As mentioned above, at the time we recommended this grant, we were primarily looking to recommend grants that we estimated were more than 8x as cost-effective as GiveDirectly, and were willing to consider recommending a limited amount of funding to grants that were between 5x and 8x as cost-effective as GiveDirectly.

  • 15.

    In our worm burden adjustment model, we estimated that Littoral has a worm burden adjustment of 1.2%, while the neighboring regions of South, West, and Southwest have worm burden adjustments of 6.5%, 6.1% and 2.3% respectively. (We did not collect worm burden data on the Centre region.)

  • 16.

    See past narrative reports, coverage surveys, and spending reports in the Sources section of our Sightsavers page.

  • 17.

    GiveWell first recommended funding to Sightsavers in 2016: GiveWell, “Our updated top charities for giving season 2016", 2016.

  • 18.

    We discuss these conversations more in detail in the page about a recent grant to Sightsavers: “In addition to Sightsavers, during the process of determining whether to recommend this grant, we spoke to the NTD Coordinators (government officials who manage NTD programs at the state level) in Niger and Kaduna states, and with representatives of CIFF, ELMA Philanthropies, END Fund, Helen Keller International's Nigeria NTDs team (a sub-grantee of Sightsavers for two of the states supported by this grant), HANDS (a sub-grantee of Sightsavers for one state), and Evidence Action's Deworm the World Initiative (see note above about support for Lagos).” GiveWell, "Sightsavers — Support for Deworming in Kaduna, Zamfara, Niger, Kano, Adamawa, and Katsina in 2021-2023 (October 2021)"