This blog is the third in a seven-part series examining the nature and reasons for the near elimination of malaria in Zanzibar since 2000. This question forms the basis of a major new research project and big conversation about malaria led by the Zanzibar Research Centre for Socio-Economic and Policy Analysis (ZRCP). A link to the full report from ZRCP can be found here. This blog follows from Part II: The Slippery Slope of Success: Why did Malaria Decline in Zanzibar after 2000?

Malaria in Zanzibar: a recap

Malaria is spread to humans through mosquito bites, with symptoms ranging from mild (fever, chills and a headache), to more severe (coma, severe anaemia, seizures, and difficulty breathing), and in too many cases death. Infants, children under 5 years, and pregnant women are at higher risk of severe infection. 

In the early 2000s, the World Health Organization (WHO) estimated there were between 300 and 500 million global cases of malaria a year, resulting in between 700,000 and 2.7 million deaths annually. During that time, 90% of the malaria disease burden was located in Africa.

New evidence on the economic and human cost of malaria in the 1990s helped inspire a renewed global elimination effort. A big push backed by global leaders, funders, and researchers and in Africa governments, health care professionals, volunteers, statisticians, and households was launched in the early 2000s, leading to a dramatic global reduction in the incidence of malaria, and after 2012, the successful trial and later in 2022 the scaling up of a malaria vaccine. After 2015 the WHO verified the complete elimination of malaria in a succession of countries.

Across Africa after 2000, the most successful countries were those that reduced the incidence of and mortality from malaria by 50%. Zanzibar went much further, to near elimination.

The Economic Benefits of Public Health

There is global evidence linking public health and economic take-offs, including Britain during the late eighteen century Industrial Revolution, the US south and Japan in the early 20^th century, and southern Europe and East Asia beginning in the 1950s and 1960s. Each surge of economic growth was supported by important breakthroughs in public health, disease control and improved nutritional intake. Data shows that between the 1960s and 1990s, for any given initial income level, countries with lower infant mortality rates experienced higher economic growth during these decades. Another study found that more than half of Africa’s growth shortfall relative to East Asia could be explained by the greater disease burden in Africa.

The Macroeconomic Consequences of Malaria

In 1995, the average income (GDP per capita) of 54 countries that faced intensive malaria was $1,526 compared to $8,268 in 96 countries with limited or no malaria burden. Between 1965 and 1990, countries with intensive malaria grew by 0.4% p.a., compared to 2.3% in countries without. Those countries who were able to eliminate  malaria typically experienced a subsequent acceleration in economic growth. Such examples include Greece, Italy, and Spain in the 1930s and 1940s, Portugal after 1958, Taiwan in 1961, Jamaica in 1958, and the Southern states of the US in the 1960s. 

The Microeconomic-Household Impact of Malaria

Research has helped to explain the household or microeconomic impact of malaria that can help explain these macroeconomic outcomes. Evidence from Malawi in the 1990s showed that the direct costs of malaria treatment were equivalent to 28% of household income among very low income households. Malaria generates a significant material demand on limited government resources in Africa. One study of Rwanda, estimated that almost 20% of the Ministry of Health budget was spent on malaria treatment. The average time lost per episode for both sick children and adults ranges from one to five days. In Kenya, primary school students were estimated to have, on average, four episodes of malaria per year and to miss on average five days of school per episode, equalling more than 10% of Kenya’s school year. The national malaria elimination program in India in the 1950s led to higher per capita household expenditures in the subsequent decades through boosting labour productivity among males.

Malaria can have more invidious impacts on schooling and workplace productivity than a mechanical accumulation of time lost in school and employment. Malaria can cause anaemia in pregnant women, which leads to a greater risk of intra-uterine (before birth) growth retardation and low birth-weight, increasing the likelihood of poor health outcomes and lost schooling later in life. The WHO estimates the scale of this benefit. In 2023 malaria treatments targeted to pregnant women averted an estimated 551,000 low-weight births, about half of these occurring in West Africa. A child that catches malaria in the first few months of life is at increased risk of permanent cognitive damage (known as ‘scarring’), leading to less lifetime learning, lower labour force productivity, and lower wages in later life. One review of 44 studies found a consistent relationship between malaria and reduced cognitive abilities and school performance of children even after recovery.

The Economic Impact of (Near) Malaria Elimination in Zanzibar: It is a Complicated Matter

Studies have shown that malaria has a significant economic impact. We should be very interested therefore in the likely positive economic benefits of malaria reduction in Zanzibar.

This is a difficult question. Some studies have found only a limited economic benefit from public health improvements One study uses global health improvements in the 1940s to estimate the impact of increased life expectancy on economic outcomes. The study finds that reduced mortality increased life expectancy but had little impact on total GDP. Another study found that the elimination of malaria could even reduce average incomes through reducing the mortality of children and diverting resources from investment to consumption and schooling. The (near) elimination of malaria it is about more than just the link between reduced mortality and economic growth. This is a difficult question because any attempt to think forward about the economic impact of (near) malaria elimination in Zanzibar needs to account for much more complicated economic and social interactions than these studies.  

The reduction of malaria is likely to impact fertility as well as mortality and both children’s attendance in school and their ability to learn in the classroom. One study combines household microdata from the Demographic and Health Surveys (DHS) across 27 countries in Sub-Saharan Africa with disaggregated data on the incidence of malaria and spending on anti-malaria interventions. The results show that anti-malaria programmes in Sub-Saharan Africa reduced infant mortality (by 5.2 percentage points), but also reduced fertility (by 0.4 births), increased adult labour supply (by 5.3 percentage points) and increased educational attainment (by 0.5 years). A similar study modelled the interaction of mortality, illness, and parental decisions related to education and fertility. The study finds that the reduced prevalence of malaria reduced fertility (by 5.9%) and led to increased school attendance (0.63 more years) for the children benefiting from the intervention. The model predicts that per capita income would rise by 34% within 60 years – a significant economic impact. The boost comes through reduced fertility and households investing more in the education of a reduced number of children.

Malaria and Economic Growth in Zanzibar: A Forgotten Question

The economic growth implication of the near elimination of malaria in Zanzibar is of first-order relevance for the government. Zanzibar Vision 2050 targets the island achieving upper middle income status by 2050.  The Vision roots this target in a backward glance at the interplay between economic growth (6.1% on average between 2009 and 2019) and population growth (2.8% annual average). As noted above economic growth and fertility decisions are both influenced in other contexts by declining malaria.

Looking forward Vision 2050 targets economic growth across the 2020s (9-10%), 2030s (7-8%), and 2040s (5.5-6.5%). Elsewhere the Vision targets an increase in tourists, from 540,000 in 2019 to 1.4 million in 2050; making Zanzibar an attractive destination for foreign investment; and that “Zanzibar needs a healthy workforce with relevant skills and talents to serve the local labour market as well as to contribute and compete as global citizens” – variables also closely influenced by malaria.

Vision 2050 does briefly acknowledge the multi-faceted benefits from having a healthy workforce, including the direct welfare benefits for people as well as the more indirect economic benefits: “Zanzibar needs a healthy workforce with relevant skills and talents to serve the local labour market as well as to contribute and compete as global citizens. The stock of human capital has to be served by adequate social services, with education and health in particular as important flows needed to mould the capable and competitive Zanzibaris of tomorrow”.

The economic benefits of health are noted only in passing and the implications are not discussed in any detail in Vision 2050. Health is headlined as a social goal for individuals, households, governments, firms, donors, and international organizations to pursue.

“A modern healthcare delivery system supported through effective investment plans and related interventions with a focus on human capital development, research, health infrastructure, medical technology, digital health systems, quality control as well as specialized medical and health practitioners and services”.

The implication is that a combination of general economic growth and policy-targeted health outcomes will boost health outcomes in Zanzibar. There is good reason to suppose this, as increased incomes provide households with the resources to pay for health care, better nutrition, education, and housing and the government with tax revenues to invest in the health care system. As one study found, the “wealthier is healthier”. Aside from the brief reference noted above, Vision 2050 makes no general references to health (or specific references to reduced malaria) as an input into development, that a healthier nation will become a wealthier nation.

Research and the Urgency of Now

The first blog in this series showed that the near-elimination of malaria in Zanzibar was a spectacular success and in with the world’s most cost-effective public health interventions. This blog has argued that malaria has long had a significant economic impact on countries where it is prevalent. The implications being that the (near) elimination of malaria in Zanzibar will have significant economic impacts – on labour productivity, on the effectiveness of schooling, on fertility, on education choices at the household level, on foreign investment, on tourism – and ultimately on economic growth. The government of Zanzibar have placed the goal of sustained rapid economic growth at the centre of their economic strategy in Vision 2050. There is an urgent need to undertake research to model the likely economic benefits of the (near) elimination of malaria in Zanzibar.

Look out for Part Four: A Delicate Balance: What are the Policy Implications of Moving Towards Malaria Elimination in Zanzibar?