Acute respiratory infection (ARI) and diarrhea remain critical public health concerns, associated with global disease burden [ 1 , 2 ]and contributing to approximately one-quarter of all mortality among children under the age of five [ 3 ]. The socioeconomic impacts on children affected by ARI and diarrhea include developmental delays, malnutrition, and diminished future educational opportunities [ 3 ]. These conditions are disproportionately prevalent in developing countries, particularly Southeast Asia, where healthcare access and sanitation infrastructure are limited [ 1 , 2 ]. In Southeast Asia, the prevalence of diarrhea ranges from 8.39% in the Philippines to 18.21% in Indonesia [ 4 ], while ARI episodes are estimated to occur at a rate of 133.9 per 1000 children under five years old [ 2 ].

In Indonesia, the Health Survey conducted by the Ministry of Health in 2022 reports an incidence rate of 4.8% for ARIs and 4.9% for diarrhea, with regional incidence rates varying according to geographic and socioeconomic factors [ 5 ]. Indeed, co-infections with multiple enteric pathogens substantially contribute to diarrheal disease in children under five, with bacterial and viral agents assuming distinct roles in modulating both disease severity and transmission pathways [ 6 , 7 ]. Indonesia has adopted the Integrated Management of Childhood Illness (IMCI) approach, which incorporates the treatment of pneumonia and diarrhea within national healthcare services [ 8 ]. Despite the significant reduction in the under-five mortality rate, from 58 per 1000 live births in 2007 to 32 per 1000 live births in 2017 [ 8 ], limitations in resources, funding, logistics, and equipment have hindered the optimal implementation of the IMCI program [ 9 ]. While IMCI was designed to enhance equitable access to childcare services for low-income families, its effectiveness has been constrained by structural challenges, implementation gaps, and insufficient continuity of care across healthcare levels [ 10 ]. These findings reinforce the association between lower socioeconomic status, malnutrition, and higher ARI rates, highlighting the need for targeted public health interventions [ 11 ], as observed in remote areas of Indonesia where efforts to address malnutrition are linked to high rates of infectious diseases in children under five [ 12 ].

An important, yet under-researched factor contributing to ARIs and diarrhea in children under five in Indonesia is the variation in modifiable risk factors across different socioeconomic groups. The Indonesian Ministry of Health has reported that socioeconomic development in eastern Indonesia tends to be lower compared to western Indonesia [ 13 ]. This is particularly evident in Eastern Indonesia, where challenges in accessing healthcare—both geographically and economically—contrast sharply with conditions in the western part of the country [ 14 ]. Low- and middle-income households in Indonesia often face inadequate access to water, sanitation, and hygiene, including unsafe drinking water, limited sanitation facilities, poor hygienic conditions, and restricted access to healthcare. These factors play a crucial role in the incidence of ARIs [ 11 ]and diarrhea among children under five. A pronounced wealth gap persists, where children from the poorest quartile experience more significant morbidity and slower reductions in the prevalence of diarrhea, ARIs, and malaria compared to those from wealthier quartiles [ 15 ]. Financial stress experienced by parents is associated with detrimental outcomes for children’s health, including increased risk of undernutrition, impaired cognitive development, and weakened immune responses, all of which contribute to greater vulnerability to diseases [ 16 ].

Indonesia continues to experience relatively higher rates of ARI and diarrhea compared to other Southeast Asian countries (e.g., Cambodia, Myanmar, and the Philippines) [ 1 , 2 ]. Currently, there is limited evidence regarding the prevalence of ARIs and diarrhea in this age group among low-middle wealth household in Indonesia. Using a large-scale Indonesia national survey, this study aimed to quantify the prevalence of ARI and diarrhea among households in the lower to middle range of the relative wealth index and identify risk factors, considering individual and household characteristics.

This study consistently demonstrates that an age of over 6 months protects against Acute Respiratory Infections (ARI) and diarrhea. For ARI, the factors contributing to children under five years old vulnerability include age, stunting, wasting, unclean cooking fuel, unimproved drinking water, and shared toilet facilities. In the case of diarrhea, all identified variables exert an association. Notably, the most significant risk factors associated with ARI and diarrhea are unclean cooking fuel and shared toilet facilities, respectively. This finding highlights that the prevalence of ARI (5.7%) and diarrhea (6.0%) among households within the low-middle wealth index surpasses the national prevalence [ 5 ]. Research conducted in Cambodia and Philippines demonstrates that the prevalence of ARI and diarrhea is higher among poor families compared to affluent families [ 16 , 27 ].

These findings found that those children aged under six months exhibit greater vulnerability to ARI, diarrhea, and malnutrition compared to older age groups. This observation is consistent with studies from economically disadvantaged areas in China and Kenya, which reveal a negative correlation between age and the risk of infection [ 28 , 29 ]. The heightened susceptibility in infants under six months can be attributed to their still-developing respiratory, digestive, and immune systems, which rely on maternal antibodies [ 28 ]. Complementary feeding increases the risk of acute diarrhea in infants and can adversely affect children’s health [ 28 , 30 ]. Furthermore, introducing pre-lacteal feeding six months before may worsen this vulnerability, as the coverage of exclusive breastfeeding in Indonesia is inconsistent across regions [ 31 ]. A study conducted in Indonesia revealed that the prevalence of pre-lacteal feeding within the first three days of life among families classified as poorest and poor were 43.39% and 46.8%, respectively [ 24 ], specifically for honey (3.5%), and water (4.9%) as pre-lacteal feeding practices [ 32 ]. Improvements in maternal education at the population level are widely acknowledged as a crucial and extensively studied determinant of child health and survival [ 3 ]. Interventions that enhance mothers’ self-efficacy can bolster breastfeeding confidence and promote the continuation of breastfeeding practices until 6 months postpartum [ 33 ]. Such measures may act as a preventative strategy against pre-lacteal feeding in infants under 6 months, thereby playing a crucial role in reducing their susceptibility to ARI and diarrhea.

This study demonstrates an association between malnutrition issues and the past two-week prevalence of ARIs and diarrhea in low- and middle-wealth households. Earlier studies in Indonesia have indicated that lower household wealth levels correlate with a heightened risk of malnutrition and ARIs [ 11 , 12 ]. A study in Philippines reported that children from lower economic families was more frequently reported compared with high economic families (79.87% vs. 20.13%) [ 27 ]. The short-term effects of this issue on impoverished families include a weakened immune system, a higher risk of developing ARI and diarrhea, as well as delays in motor skills and cognitive and social development during childhood [ 34 ]. Research in Indonesia also reported that the poorest districts exhibited a significantly higher prevalence of underweight, wasting, and stunting than the wealthiest districts [ 35 ]. This aligns with findings indicating that malnutrition issues and morbidity distribution is more prevalent outside of Java and Bali, which are closely associated with areas of high wealth index [ 36 ]. Limited access to healthcare services and proper sanitation facilities outside of Java and Bali complicates malnutrition and morbidity issues for low- and middle-wealth households, making them increasingly complex and challenging to address [ 37 ].

This study emphasizes that inadequate household sanitation support can increase the risk of ARIs and diarrhea among children. The findings of this study indicate that 16.1% of households utilize unclean cooking fuel, with 1.3% suffering from ARI. Those using unclean cooking fuel have a 1.57 times greater risk of ARI infection. Regarding diarrhea, 9.7% of households with shared toilet facilities report cases, with 0.8% affected, and individuals in these households have a 1.45 times higher risk of experiencing diarrhea. These results align with other national-level studies in the Philippines, Cambodia and Myanmar that reported lack of sanitation and cooking fuel among low-middle wealth household might increase the risk of ARIs and diarrhea [ 16 , 27 , 38 ]. Indonesia’s achievements in reducing the use of residual cooking fuels, coupled with the support of social protection programs, should be expanded to further enhance the health outcomes of children under five. These efforts could also be adapted and scaled within the broader Southeast Asian region. This study found that social protection support is vital in preventing ARI and diarrhea issues among families with low to middle-wealth status. This study underscores the risks of ARIs, diarrhea, and malnutrition in groups lacking social protection guarantees. The conversion of clean cooking fuel in Indonesia, aimed at reduction of indoor pollution in low- and middle-income households [ 39 ]while Social protection policies and programs can offer a crucial safety net for children and caregivers from vulnerable households by alleviating poverty and addressing the underlying determinants of malnutrition [ 40 ]. Furthermore, research in Indonesia indicates that the food voucher program (Bantuan Pangan Non Tunai) increased dietary diversity among poor households by at least 15 percentage points compared to those that continued to receive in-kind food transfers. Additionally, this new initiative has enhanced the consumption of essential nutrients among impoverished households and improved the targeting effectiveness of social welfare programs [ 41 ]. Indonesia has successfully strengthened its social protection system for low- and middle-income communities in addressing the challenges posed by the COVID-19 pandemic. The rice in-kind transfer program ( "Rastra" ) was gradually replaced by a food voucher program ( "Sembako" ), which aims to diversify diets among vulnerable households. [ 42 ]. The combination of social protection systems in Indonesia is crucial in giving households the flexibility to choose food according to their preferences [ 41 ]. Strengthening and developing the implementation of pro-poor health and social program policies is essential to enhance the participation of low- to middle-wealth index households in accessing healthcare and education, including preventing infectious diseases in young children.

While the present study has primarily focused on socioeconomic and environmental determinants of childhood diarrhea, it is imperative to acknowledge that co-infections with multiple enteric pathogens may also constitute a critical, yet underexplored, component of the disease’s etiology. Although our analysis did not encompass this dimension, extant evidence suggests that the interplay between bacterial and viral pathogens can synergistically exacerbate disease severity, particularly in settings characterized by inadequate sanitation [ 6 , 43 ]. This observation underscores the necessity for integrated sanitation and infection control strategies that concurrently address both bacterial and viral transmission routes [ 44 ]. Emphasizing this aspect is essential for guiding the design and implementation of differentiated targeted preventive measures aimed at mitigating the overall burden of diarrheal disease in vulnerable populations.

This study employs a large sample size that encompasses nearly all children under five across various districts and cities in Indonesia nationally; however, it faces certain research limitations. First, although the principal component analysis approach has been widely used in other studies to measure household wealth levels, its application has inherent constraints within this context [ 45 ]. However, the household wealth index in this study heavily relies on the selected parameters, and not all the parameters adequately reflect the family’s welfare conditions. The validity of this approach should be further tested with different study designs and parameters. Second, this study employs a cross-sectional approach, which limits the ability to draw causal conclusions over time. Third, there is a potential for bias, as parent respondents may misremember or forget conditions from the two weeks before the interview, particularly regarding clinical symptoms of ARI and diarrhea in their children. Additionally, limited access to healthcare services in Indonesia may lead to undiagnosed cases of ARI and diarrhea, potentially affecting the research outcomes. Despite these limitations, this study provides crucial information regarding the risk factors for ARI and diarrhea among Indonesia’s low- and middle-income households. Furthermore, it is the first to report on the impact of social protection on malnutrition issues and the incidence of ARI and diarrhea in children under five from low- to middle-wealth families. This can assist the government in strengthening pro-poor implementation policies through the social protection system. The results provide a basis for future research and support the design and implementation of targeted prevention strategies for ARIs and diarrhea, as well as informing poverty reduction programs and addressing health challenges among children health-related SDGs.

This study highlights the need for targeted interventions to address malnutrition, poor sanitation, and limited social protection, which contribute to the high rates of ARI and diarrhea among children under five in low- and middle-income households in Indonesia. Recommendations include strengthening social protection programs, improving access to clean water and sanitation, and advocating for policies that reduce poverty and enhance income support through direct transfers and child benefits, particularly in vulnerable communities.