One of our two new top charities this year is Helen Keller International (HKI)’s vitamin A supplementation program. We named HKI’s vitamin A supplementation program a top charity this year because:

• There is strong evidence from many randomized controlled trials of vitamin A supplementation that the program leads to substantial reductions in child deaths.
• HKI-supported vitamin A supplementation programs are inexpensive (we estimate around $0.75 in total costs per supplement delivered) and highly cost-effective at preventing child deaths in countries where HKI plans to work using GiveWell-directed funds.
• HKI is transparent—it has shared significant, detailed information about its programs with us, including the results and methodology of monitoring surveys HKI conducted to determine whether its vitamin A supplementation programs reach a large proportion of targeted children.
• HKI has a funding gap—we believe it is highly likely that its vitamin A supplementation programs will be constrained by funding next year.

HKI’s vitamin A supplementation program is an exceptional giving opportunity, but as is the case for donating to any of our other top charities, not a “sure thing.”

I’m the Research Analyst who has led our work on HKI this year. In this post, I discuss some key questions about the impact of Helen Keller International’s vitamin A supplementation program and what we’ve learned so far. I also discuss GiveWell’s plans for learning more about these issues in the future.

In short:

• Is vitamin A deficiency still a major concern? Our best guess is that vitamin A deficiency is considerably less common today where HKI works than it was among children who participated in past trials of vitamin A supplementation, but not so rare that vitamin A supplementation would not be cost-effective. We are quite uncertain about our estimate of the prevalence of vitamin A deficiency where HKI works because little high-quality, up-to-date data on vitamin A deficiency is available. We plan to consider funding new surveys of vitamin A deficiency to improve our understanding of the effectiveness of HKI’s programs.
• Have improvements in health conditions over time reduced the need for vitamin A supplementation? Child mortality rates remain quite high in areas where HKI plans to use GiveWell-directed funding for vitamin A supplementation programs. We think it’s unlikely that health conditions in these countries have improved enough for vitamin A supplementation to no longer be effective.
• How strong is HKI’s track record of supporting fixed-point vitamin A supplement distributions? HKI expects to primarily support fixed-point vitamin A supplement distributions (rather than door-to-door campaigns) going forward. Results from monitoring surveys have found that, on average, HKI’s fixed-point programs have not reached as high a proportion of targeted populations as its door-to-door programs, but these monitoring surveys may not have been fully representative of HKI’s programs overall. Our best guess is that future fixed-point programs will achieve moderate to high coverage.

Is vitamin A deficiency still a major concern?

Vitamin A deficiency, a condition resulting from chronic low vitamin A intake, can cause loss of vision and increased severity of infections. If vitamin A deficiency is less common today than it was among participants in trials of vitamin A supplementation, today’s programs may prevent fewer deaths than the evidence from the trials suggests.

We estimate that the prevalence of vitamin A deficiency was high (around 60%) in the populations studied in trials included in the Cochrane Collaboration review of vitamin A supplementation programs for preschool-aged children, Imdad et al. 2017.¹See the “Imdad 2017 – VAD prevalence estimates” sheet here for details.

The map below, from Our World in Data, presents the World Health Organization (WHO)’s most recent estimates of the prevalence of vitamin A deficiency among preschool-aged children by country, covering the period from 1995 to 2005. WHO categorizes prevalences of vitamin A deficiency among preschool-aged children of 20% or above as a severe public health problem.²WHO Global prevalence of vitamin A deficiency in populations at risk 2009, Pg 8, Table 5.

Since WHO’s most recent estimates are now considerably out-of-date, we decided to investigate a variety of additional sources in order to create best-guess estimates of rates of vitamin A deficiency today in countries in sub-Saharan Africa where HKI works.

We learned that there is very little useful, up-to-date data on vitamin A deficiency in countries in sub-Saharan Africa. In many countries, the most recent surveys of vitamin A deficiency were completed ten or more years ago. Many governments have also recently mandated the fortification of vegetable oil or other foods with vitamin A, but little information is available on whether foods are actually adequately fortified in practice.³See this spreadsheet for the information we collected on the most recent vitamin A deficiency surveys and on vitamin A fortification programs in countries where HKI has supported vitamin A supplementation programs.

Taking the limited available data into account, our best guess is that prevalence of vitamin A deficiency in countries where HKI works today is likely to be considerably lower than the prevalence of vitamin A deficiency among children who participated in vitamin A supplementation trials—closer to 20% prevalence than 60% prevalence.

We find that HKI’s vitamin A supplementation programs still appear highly cost-effective, even when taking our estimate of the change in the prevalence of vitamin A deficiency over time into account (see our most recent cost-effectiveness analysis for full details). But we remain quite uncertain about our estimate of the prevalence of vitamin A deficiency in countries where HKI works—new information could cause us to update our views on HKI’s cost-effectiveness considerably.

Next year, we’ll continue to follow research relevant to estimating vitamin A deficiency rates where HKI works. We also plan to consider funding new vitamin A deficiency surveys ourselves through a GiveWell Incubation Grant.

Have improvements in health conditions over time reduced the need for vitamin A supplementation?

In a blog post last year, we wrote that vitamin A supplementation has a mixed evidence base. There is strong evidence from many randomized controlled trials conducted in the 1980s and 1990s that the program reduces child mortality, but a more recent trial in northern India with more participants than all the other trials combined (the Deworming and Enhanced Vitamin A trial, or DEVTA) did not find a statistically significant effect.

There have been broad declines in child mortality rates over the past few decades. Participants in the control group in the DEVTA trial had a mortality rate of 5.3 deaths per 1,000 child-years, lower than the mortality rates in the control groups in earlier trials that found statistically significant results (ranging from 10.6 to 126 deaths per 1,000 child-years). One potential explanation for the difference between the results of the DEVTA trial and earlier trials is that the some types of deaths prevented by vitamin A supplementation in previously studied populations had already been prevented through other means (e.g., increased access to immunizations and medical care) in the DEVTA population.

We looked into child mortality rates in countries in sub-Saharan Africa where HKI plans to use GiveWell-directed funding in the near future—Guinea, Burkina Faso, and Mali—as well as other countries where HKI has recently worked. Mortality rates among preschool-aged children in Guinea, Burkina Faso and Mali remain quite high—around 13 deaths per 1,000 child-years, within the range of mortality rates among control groups in vitamin A trials that found statistically significant results.⁴The control group mortality rate in the DEVTA trial was 5.3 per 1,000 child-years. See this spreadsheet for child mortality rates in Burkina Faso, Guinea, and Mali (13 deaths per 1,000 child-years is the simple average of “Average of GBD and UN IGME data” child mortality rates for the three countries), and see here for more information on control group mortality rates in other vitamin A supplementation trials. Based on these high child mortality rates, we don’t believe it’s very likely that overall health conditions have improved enough in these countries for vitamin A supplementation to no longer be effective at preventing deaths.

It is also possible that changes in causes of child deaths between the 1980s and 1990s and today could mean that vitamin A supplementation is now less effective than it was in the past. Different vitamin A experts have different views on whether vitamin A primarily prevents deaths due to a few specific causes (we’ve seen diarrhea and measles most frequently pointed to) or whether it reduces deaths due to a wider range of conditions by, perhaps, strengthening the immune system against infection. In our view, the research on this is inconclusive. According to the data we’ve seen, infectious disease overall and diarrhea in particular cause a similar proportion of total deaths among young children today as they did in the 1980s and 1990s; measles causes a substantially lower proportion of total deaths today than it did in the past.⁵See the final bullet point in this section of our review of HKI for more on this topic. We’ve added an adjustment to our cost-effectiveness analysis to account for changes in the composition of causes of child mortality since the vitamin A trials were implemented—HKI’s work still appears highly cost-effective following this adjustment.

We may conduct additional research next year to learn about child mortality rates in places where HKI works at a more granular (e.g., regional or sub-regional) level. We may also conduct additional research on the impact of changes in cause-specific mortality rates on the effectiveness of vitamin A supplementation.

How strong is HKI’s track record of supporting fixed-point vitamin A supplement distributions?

In many past HKI-supported campaigns, healthcare workers have traveled door-to-door to administer vitamin A supplements to preschool-aged children. Funding was already available from other sources for sending teams of healthcare workers door-to-door to administer polio vaccinations, and adding vitamin A supplementation to these campaigns was relatively simple and cheap.

In fixed-point distributions, caregivers are expected to bring their children to a central location to receive vitamin A supplements. Due to recent progress in polio elimination, many door-to-door programs have recently been scaled-down or eliminated, so HKI expects to primarily be supporting fixed-point distributions going forward.

It may be more challenging to reach a large proportion of a targeted population with fixed-point distributions. HKI’s recent monitoring surveys have found that, on average, its door-to-door distributions have achieved higher coverage rates (around 90%) than its fixed-point distributions (around 60%). The average of around 60% for fixed-point programs reflects surveys finding high coverage in a few campaigns in the Democratic Republic of the Congo and Mozambique, and relatively low coverage in campaigns in Nigeria, Tanzania, and Kenya.

A complication for assessing HKI’s track record is that HKI often chose to conduct coverage surveys in areas where it expected coverage to be particularly low, so we would guess that these results are not fully representative of HKI’s work on fixed-point distributions.

Based on the available information, our best guess is that HKI-supported fixed-point vitamin A supplementation distributions next year will achieve moderate to high coverage.⁶To be more precise about what I mean: in Guinea (the program I am most familiar with, following our site visit in October), I’m 70% confident that coverage surveys representative of the distribution as a whole will indicate that the first vitamin A supplement distribution in 2018 reached at least 55% of targeted children across the country. HKI has told us that it will conduct representative monitoring surveys (not only in areas where it expects coverage to be low) following its vitamin A supplement distributions supported with GiveWell-directed funding next year—we expect that these surveys will provide data useful for assessing how successful the programs were overall.