By Lina Sorg
Child wasting—when one is too thin for a given height, either as the result of rapid weight loss or insufficient weight gain—is the most visible and life-threatening manifestation of acute malnutrition. It affects roughly 6.8 percent (roughly 45 million) of children around the world, with the highest concentration of cases in South Asia. Wasting occurs due to maternal malnutrition, low birthweight, insufficient feeding and care practices, infection, and limited access to safe drinking water. Affected individuals suffer from weakened immune systems and a higher incidence of developmental delays, disease, and even death.
The relationship between wasting/malnutrition and rate of infection is a viscous cycle that devastates the health and development of children in impoverished nations (see Figure 1). The weight loss, impaired immunity, and mucosal damage of malnutrition make victims more susceptible to a variety of infections, which subsequently cause loss of appetite, reduced nutrient intake, and malabsorption — all of which restart the cycle of malnutrition.
Current interventions to combat undernutrition often attempt to increase the engagement of mothers and children with the health sector. One strategy involves packaging nutrition-specific approaches—like small-quantity lipid-based nutrient supplements (SQ-LNS)—with interventions such as immunization to support overall child health. SQ-LNS are food-based supplements that are meant to prevent malnutrition in children between six and 24 months of age (see Figure 2); just one supplement per day reduces severe wasting in this age group by 31 percent, severe stunting by 17 percent, and mortality 27 percent. “Intentionally packaging nutrition-specific care with routine immunization could lead to enhanced effectiveness in reducing undernutrition while also improving prevention efforts against infectious disease,” Navideh Noori of the Bill & Melinda Gates Foundation's Institute for Disease Modeling said.
Figure 1. The cyclical relationship between wasting/malnutrition and rate of infection of acute diseases, particularly in children. Figure courtesy of Navideh Noori.
During the 10th International Congress on Industrial and Applied Mathematics, which is currently taking place in Tokyo, Japan, Noori modeled the advantageous impacts of mass nutritional supplementation initiatives to control measles infections. Malnutrition is a primary contributor to diseases like measles: a highly contagious, airborne viral infection that is especially common in children. Despite the widespread existence of a safe and cost-effective vaccine, only 83 percent of children in 2022 had received one dose by their first birthday — the lowest rate of vaccination since 2008. Most measles-related deaths occur among unvaccinated or under-vaccinated children who are less than five years of age.
Outbreaks of vaccine-preventable diseases like measles are common in the West African country of Niger, where the city of Zinder routinely records some of the highest malnutrition rates in the world. In 2022, wasting and stunting among children between six and 24 months in Niger were estimated at 18 and 51 percent. An initiative called the “1,000 Days” project—a partnership of the Alliance for Medical Action and BEFEN (the Wellbeing of Women and Children in Niger)—aims to improve the outlook in the Zinder region. The project delivers preventive and curative care in the form of nutritional supplementation, vaccination and medical follow-up, and malnutrition warning signs to pregnant women and children under two years of age. “Nutritional commodities may be perceived as an incentive to draw patients to health centers where other services may be offered,” Noori said, adding that the 1,000 Days program has led to an increase in the first dose of measles vaccine uptake.
Given these encouraging results, Noori sought to quantify the impact of two factors on measles morbidity and mortality: (i) Therapeutic feeding on wasted children and (ii) mass supplementation of SQ-LNS prior to wasting. She created a dynamic, population-level model of measles transmission that is stratified by nutrition status and informed by the dynamics of existing data. The model accounts for the cycle/relapse of some of the treated/recovered children and operates under the assumption that nutritional interventions increase recipients’ engagement with the health sector and heighten vaccination rates among children among children.
Noori utilized Latin hypercube sampling and partial rank correlation coefficient sensitivity analysis to explore the parameters’ effects on model outcomes. She identified two major parameters—measles-induced mortality probability and susceptibility impact of measles infection—that have the strongest influence on measles infection and mortality outcomes. Noori then used her model to consider three scenarios: (i) Treatment in the form of therapeutic feeding of wasted children, (ii) prevention, wherein 60 percent of individuals receive SQ-LNS regardless of their nutrition status, and (iii) a combination of both treatment and preventative measures.
Noori found that the third scenario—the use of treatment and prevention—yielded the most effective outcome. For a population of 100,000 individuals, this combination reduced measles infection among wasted children from 16,000 to 4,500 and mortality from 2,300 to 630. “The effect of mass nutritional supplementation on reducing the number of wasted children and therefore reducing measles burden among wasted children leads to sizable reductions in measles cases and mortality above and beyond either intervention alone,” Noori said. This is because people who engage with the health sector to receive SQ-LNS can simultaneously receive a measles vaccine. Coupling nutritional supplementation with vaccination is also more cost effective than individual wasting treatments, which can put financial and logistical pressures on vulnerable, poorly resourced health systems.
Ultimately, Noori hopes that this work will highlight the value of SQ-LNS and similar nutritional efforts in preventing childhood infection of measles and other severe diseases in developing countries. “Our work may elevate the potential role of nutritional supplementation in infection prevention and encourage more targeted data collection around the effectiveness of packaged care in optimizing child development and growth,” she said.
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Lina Sorg is the managing editor of SIAM News. |