Global, regional and national burden and time trends of malaria in children and young adolescents under 15 years from 1990 to 2021: a worldwide observational study

Abstract

Background

The global burden of malaria among children remains severe; however, there is a dearth of comprehensive studies comparing this burden across different countries and regions. This study aims to analyze the patterns and trends in malaria burden among children under the age of 15 at global, regional, and national levels from 1990 to 2021, and to investigate the correlation between malaria burden and the developmental status of different countries.

Methods

This observational study utilized data from the Global Burden of Diseases Study to examine incidence and mortality rates of malaria in children under 15 between 1990 and 2021. The rates and absolute number of malaria cases and deaths showed the epidemic status of malaria. The estimated annual percentage change (EAPC) quantified the time trends of malaria burden. Nonlinear regression was conducted to explore the association between the Socio-demographic Index (SDI) and rates across countries from 1990 to 2021.

Results

In 2021, there were 169,052,260 malaria cases and 469,881 deaths among children under 15 worldwide, with an incidence rate of 8402.78 per 100,000 and a mortality rate of 23.36 per 100,000. From 1990 to 2021, the global incidence rate of malaria in children under 15 showed a slight increase of 0.87% annually from 2015 to 2021, while the mortality rate decreased by 0.69% per year from 1990 to 2015 but remained stable thereafter. Additionally, there was a notable increase in the number of deaths and mortality rate from malaria in 2020 and 2021 compared to 2019. The most affected regions were in Sub-Saharan Africa, with Western, Eastern, and Central regions having the highest number of cases and deaths. Analysis by SDI indicated that low SDI regions experienced the highest burden of malaria, although all regions saw the highest incidence and mortality rates in children under 5. Despite improvements in mortality rates from 1990 to 2015, some regions such as Oceania, the Caribbean, Tropical Latin America, and North Africa and the Middle East observed increasing trends in incidence rates post-2015.

Conclusion

Improving socio-economic conditions is urgently needed to alleviate malaria-related morbidity and mortality among children. Our results highlight the need for targeted national policies and stronger international cooperation, especially in regions with low SDI and significant disparities. With concerted efforts, we can significantly reduce malaria’s impact and move closer to a malaria-free world.

Introduction

Malaria, which is caused by a parasite that is transmitted to the human host by mosquitoes of the genus Anopheles, remains a major public health challenge and has a devastating impact on people’s health and livelihoods worldwide despite being preventable and curable. According to the World Malaria Report 2023, the global malaria burden increased in 2022, with an estimated 249 million cases, which is 5 million more than the pre-pandemic level in 2019 [1]. The African Region continues to carry the majority of the malaria burden, accounting for approximately 93.6% of cases and 95.4% of deaths globally [1]. In 2015, the baseline year of the Global technical strategy for malaria 2016–2030 (GTS), there were an estimated 230 million malaria cases. The GTS set its first milestone in 2020 to reduce malaria cases and deaths by at least 40%, compared with 2015 [2]. Although significant progress has been made since 2000 in averting cases and deaths, the world is still off track in achieving the GTS 2025 milestones [1]. There remains an urgent need for action to get back on track, considering the ongoing challenges posed by climate change, biological threats, humanitarian crises, and funding constraints.

Previous meta-analysis indicates that mixed infections and Plasmodium falciparum infections are more likely to develop into severe malaria, with 9% of mixed Plasmodium infections progressing to severe malaria. These cases are more prone to severe anemia, pulmonary complications, and multi-organ failure compared to single infections [3]. A review of the epidemiological characteristics of severe malaria caused by Plasmodium vivax infection in India showed that 29.3% of P. vivax infections developed into severe malaria, mainly manifested as jaundice (37.4%), severe thrombocytopenia (37.2%), multi-organ dysfunction (24.2%), and severe anemia (20.4%). The mortality rate of severe malaria caused by P. vivax infection varied from 0 to 12.9% in the included studies [4]. Severe malaria is also the main cause of malaria-related deaths in sub-Saharan Africa, especially among children under 5 years old, as a substantial proportion of older children and adults have acquired immunity to malaria [5]. A study from East Africa found that for every 25% increase in community malaria prevalence, the annual rate of severe malaria hospitalization doubled. Regardless of transmission intensity, severe malaria was mainly concentrated in children under 5 years old. Previous meta-analyses have reported varying malaria prevalence rates among children in Ethiopia, with one study finding a pooled prevalence of 22.03% for children under five [6], and another study reporting an overall prevalence of 9.07% among children in general [7]. However, in low-transmission settings, older children were at increased risk of severe malaria [8], and changes in immunity patterns across different age groups mean that older children may also be more susceptible to severe malaria.

Therefore, understanding the prevalence of malaria globally and in different regions and countries, particularly among children under 5 and older children, is critical for the development of effective prevention and treatment strategies. Previous research has indeed underscored a significant burden of malaria among children, revealing that the incidence rate in children under 5 years old surpasses all other age groups. However, this study primarily describes the incidence of malaria and does not provide a detailed account of mortality rates. Furthermore, while it encompasses all age groups, it provides only a limited and less focused analysis on the specific impact of malaria on children. Additionally, previous studies had shown the great impact of the COVID-19 pandemic on malaria mortality [9, 10]. Therefore, it is essential to conduct more targeted and recent studies to fully understand the current toll of this disease on the pediatric population in the context of the global health crisis.

In the present study, our objective was to examine the global, regional, and national patterns and trends in the burden of malaria among children under 15 years of age, spanning from 1990 to 2021. This analysis utilized data from the 2021 Global Burden of Disease Study (GBD 2021). Furthermore, we sought to investigate the correlation between the burden of malaria and the developmental status of various countries, employing the Socio-demographic Index (SDI) for 204 countries and territories. Our research offers a comprehensive viewpoint, facilitating a deeper comprehension of the long-standing trends and regional differences in the incidence and mortality rates of malaria. This understanding is instrumental in formulating more scientifically robust and effective global strategies aimed at eradicating malaria.

Methods

Study design and data source

This was an observational study using data obtained from the 2021 Global Burden of Disease Study (GBD 2021) result tools (http://ghdx.healthdata.org/gbd-results-tool). The GBD study consists of a systematic and scientific effort to quantify the comparative magnitude of health losses due to diseases by sex, age and location over time [11].

Variables

Annual data from 1990 to 2021 of malaria case number, incidence rates, death number, and mortality rates with their 95% uncertainty interval (UI) in children and younger adolescents under 15 were extracted. The Socio-demographic Index (SDI) of 204 countries and territories from 1990 to 2021 was also extracted from the GBD 2021 result tools. The SDI is a composite indicator of development status strongly correlated with health outcomes. It is the geometric mean of 0 to 1 indices of total fertility rate under the age of 25, mean education for those ages 15 and older, and lag distributed income per capita. As a composite, a country with an SDI of 0 would have a theoretical minimum level of development relevant to health, while a country with an SDI of 1 would have a theoretical maximum level [12].

Data collection and processing

Data was gathered from the GBD 2021 result tools, established by the GBD group [13]. The general methodological approaches to estimate the incidence and mortality of malaria were described elsewhere [14]. Briefly, estimating malaria incidence and mortality is a multi-step process that begins with the collection of data from routine case reports, geolocated infection rate surveys, and assessments of coverage for malaria control interventions, complemented by environmental and socio-economic factors. Bayesian spatiotemporal geostatistical models are then applied, tailored to the specific conditions of regions such as sub-Saharan Africa and areas beyond. These models predict infection rates which are subsequently converted into clinical incidence rates. The incidence rates are combined with population data to estimate total cases, which are then translated into measures of disease burden. Adjustments are made for the impact of COVID-19 on health service disruptions during 2020 and 2021, and a systematic review and meta-analysis of the literature is conducted using the PRISMA flow diagram to ensure a comprehensive evaluation of the evidence [14].

We reported malaria incidence and death data in children and younger adolescents under 15 in 204 countries and territories, which were classified into 5 regions by the SDI. The 204 countries and territories were also divided into 21 regions (Central Asia, Western Europe, Central Sub-Saharan Africa, et al.) based on their epidemiological homogeneity and geographical contiguity. For a detailed list of countries included in each GBD region, please refer to the Supplementary table. Furthermore, we additionally reported the results by three age groups, including < 5 years, 5 to 9 years, and 10 to 14 years.

Statistical analysis

The absolute number of malaria cases and deaths represents the actual status of malaria burden in children under 15 globally, regionally, and nationally. Its relative change was defined as $\:\frac{{Number}_{2021}-{Number}_{1990}}{{Number}_{1990}}\times\:100\%$, which showed the overall change between 1990 and 2021.

The Estimated Annual Percentage Change (EAPC) is a commonly used tool to quantified the rate trend over a specific interval [15, 16]. A regression line was fitted to the natural logarithm of the rates (y = α + βx + ε, where y = ln(rate) and x = calendar year). EAPC was calculated as $\:\:({e}^{\beta\:}-1)\times\:100\%$, with 95% confidence intervals (CIs) obtained from the linear regression model. The term “increase” was used to describe trends when the EAPC and its lower boundary of 95% CI were both > 0. In contrast, “decrease” was used when the EAPC and its upper boundary of 95% CI, were both < 0. Otherwise, the term “stable” was used.

In this study, we calculated the relative changes and EAPCs across three distinct time periods: from 1990 to 2021, from 1990 to 2015, and from 2015 to 2021. This approach was undertaken to examine the shifts in the burden of malaria and its trends subsequent to the establishment of the Global Technical Strategy for Malaria 2016–2030 (GTS).

Finally, we conducted a non-linear regression (second order polynomial) to explore the association between SDI and malaria incidence and mortality rates in 204 countries and territories throughout 1990 to 2021. A regression curve was fitted to the rates (y = α + βx + γx², where y = the value of rates and x = SDI).

Results

Global and National burden and time trends

In 2021, there were 169,052,260 cases of malaria among children under the age of 15 worldwide, with an incidence rate of 8402.78 per 100,000 individuals. The incidence rate increased by an average of 0.87% per year from 2015 to 2021 (95% CI, 0.28–1.45%). From 1990 to 2015, there was no significant change in the global incidence of malaria (EAPC = 0.01%, 95% CI, -0.30–0.31%) (Table 1). In 2021, 469,881 children under the age of 15 died from malaria worldwide, with a mortality rate of 23.36 per 100,000 individuals. The mortality rate decreased by an average of 0.69% per year from 1990 to 2015 (95% CI, 0.22–1.15%), with no significant change from 2015 to 2021 (EAPC=-0.79%, 95% CI, -3.49–1.91%) (Table 2). At the global level, there is little difference in malaria between genders, with males slightly lower than females. In 2021, the incidence rates of malaria were 8225.58 per 100,000 males and 8591.71 per 100,000 females, and the mortality rates were 23.00 per 100,000 males and 23.74 per 100,000 females (Tables 1 and 2).

Table 1 Malaria incidence rates among children under 15 in 1990, 2015, and 2021, and their trends between 1990–2015, and 2015–2021

Table 2 Malaria mortality rates among children under 15 in 1990, 2015, and 2021, and their trends between 1990–2015, and 2015–2021

As shown in Fig. 1, among different countries in 2021, the highest number of malaria cases in children under the age of 15 was in Nigeria, with 52,234,184 cases, followed by the Democratic Republic of the Congo and Uganda, with 19,646,828 and 7,488,947 cases, respectively. The three countries with the highest incidence rates of malaria were Benin, Liberia, and Burkina Faso, with rates of 65,668.52 per 100,000, 64,880.12 per 100,000, and 63,761.98 per 100,000, respectively. Although the Democratic People’s Republic of Korea and Venezuela had relatively low incidence rates of malaria in 2021 (13.77 per 100,000 and 1,116.94 per 100,000, respectively), both countries have seen an upward trend in the incidence rate of malaria from 1990 to 2021, with the Democratic People’s Republic of Korea increasing by an average of 49.76% per year (95% CI, 28.88–70.64%) and Venezuela increasing by an average of 7.90% per year (95% CI, 5.07–10.73%). Furthermore, from 2015 to 2021, 15 countries saw an upward trend in the incidence rate of malaria, with the fastest increase in Costa Rica, which saw an average annual increase of 168.03% (95% CI, 40.41–295.65%), followed by Nicaragua and Djibouti, with average annual increases of 49.81% (95% CI, 31.59–68.02%) and 39.83% (95% CI, 24.93–54.73%), respectively.

Fig. 1

The global trends in malaria infection and deaths in children under 15 in 204 countries and territories. (A) malaria incidence number and rates in 2021; (B) the EAPCs of malaria incidence rates from 1990 to 2021; (C) malaria death number and mortality rate in 2021; (D) the EAPCs of malaria mortality rates from 1990 to 2021

In 2021, Nigeria, the Democratic Republic of the Congo, and Uganda also had the highest number of deaths from malaria in children under 15, with 139,037, 50,928, and 35,941 deaths, respectively. Additionally, the country with the highest mortality rate was Burkina Faso, with 212.08 per 100,000, followed by Sierra Leone and Niger, with 195.31 per 100,000 and 185.83 per 100,000, respectively. The Democratic People’s Republic of Korea and Venezuela also saw an upward trend in malaria mortality rates from 1990 to 2021, increasing by an average of 12.88% per year (95% CI, 5.72–20.05%) and 4.20% per year (95% CI, 0.86–7.55%), respectively. Between 2015 and 2021, four countries saw an upward trend in malaria mortality rates, with the fastest increase in Nicaragua, rising by an average of 60.85% per year (95% CI, 33.67–88.03%), followed by Angola, Burundi, and South Sudan, with average annual increases of 5.52% (95% CI, 1.78–9.27%), 4.81% (95% CI, 3.11–6.51%), and 4.57% (95% CI, 1.36–7.77%), respectively.

Diversities in malaria burden of 21 GBD regions

The burden of malaria in children under 15 is most severe in the Sub-Saharan African Regions. From 1990 to 2021, among the 21 GBD regions, the three regions with the highest number of malaria cases were Western, Eastern, and Central Sub-Saharan Africa, with the number of cases in children under 15 in 2021 being 99,760,799, 34,800,055, and 27,942,719, respectively. From 1990 to 2015, the incidence of malaria in children under 15 in all GBD regions decreased, except for Southern Sub-Saharan Africa, where the incidence of malaria remained stable during this period. Central and Western Sub-Saharan Africa had the highest incidence of malaria in children under 15 in 2021, with rates of 47,617.49 per 100,000 and 46,451.42 per 100,000, respectively, followed by Oceania with 19,988.00 per 100,000. The incidence of malaria in Oceania increased from 2015 to 2021, with an average annual increase of 10.59% (95% CI, 4.37–16.81%). Apart from Oceania, the incidence of malaria in the Caribbean, Tropical Latin America, and North Africa and Middle East also increased from 2015 to 2021, with EAPCs of 10.73% (95% CI, 4.13–17.33%), 10.02% (95% CI, 1.43–18.60%), and 9.89% (95% CI, 5.51–14.27%), respectively (Table 1).

In 2021, in regions with a high prevalence of malaria (such as Central, Western and Eastern Sub-Saharan Africa, and Oceania), the incidence of malaria was much higher in children under 5 years old than in the 5–9 and 10–14 age groups. However, in regions with a relatively low prevalence of malaria (such as South Asia, Andean Latin America, Southeast Asia, Caribbean, East Asia, etc.), the incidence of malaria was highest in the 10–14 age group in 2021 (Fig. 2).

Fig. 2

Comparison of malaria incidence and mortality rates among < 5 years group, 5–9 years group, and 10–14 years group in 21 GBD regions in 1990, 2015, and 2021

From 1990 to 2021, the number of deaths from malaria in children under 15 was highest in Western Sub-Saharan Africa, reaching 279,260 in 2021, followed by Eastern and Central Sub-Saharan Africa, with 105,109 and 67,238 deaths from malaria in 2021, respectively. Western, Central, and Eastern Sub-Saharan Africa were also the regions with the highest mortality rates from malaria in children under 15 in 2021, with rates of 130.03 per 100,000, 114.58 per 100,000, and 58.91 per 100,000, respectively. All regions saw a decrease in the mortality rate from malaria from 1990 to 2021, except for Southern Sub-Saharan Africa, where the mortality rate from malaria in children under 15 increased by an average of 3.21% per year (95% CI, 1.87–4.55%) from 1990 to 2015 (Table 2). The mortality rate from malaria was highest in children under 5 in the vast majority of regions, with little difference in the mortality rate from malaria between the 5–9 and 10–14 age groups (Fig. 2).

Diversities in malaria burden of 5 SDI regions

The incidence of malaria and malaria-related mortality among children under 15 vary significantly across different SDI Regions. Although the incidence of malaria in the Low SDI region showed a downward trend from 1990 to 2021 (with EAPC from 1990 to 2015 being − 1.45% (95% CI, -1.7% to -1.2%), and − 0.68% (-1.07% to -0.29%) from 2015 to 2021), the incidence of malaria in children under 15 in the Low SDI region is far higher than in other regions, with 120,555,085 cases in 2021, and an incidence rate of 26,194.78 per 100,000. This is followed by the Low-middle and Middle SDI regions, with incidence rates of 6,756.82 per 100,000 and 1,626.58 per 100,000 in children under 15 in 2021, respectively. However, the incidence of malaria in children under 15 in the Low-middle and Middle SDI regions showed an upward trend between 2015 and 2021, with an average annual increase of 1.86% (95% CI, 0.93–2.78%) and 7.72% (95% CI, 6.47–8.97%), respectively (Table 1).

The mortality rate from malaria in children under 15 is also highest in the Low SDI region, reaching 76.83 per 100,000 in 2021, followed by the Low-middle and Middle SDI regions, with rates of 17.74 per 100,000 and 4.38 per 100,000, respectively. The mortality rates from malaria in these three regions all showed a downward trend from 1990 to 2015, but remained stable from 2015 to 2021 (Table 2).

The High and High-middle SDI Regions maintained a low prevalence of malaria from 1990 to 2021, with incidence rates of 0.03 per 100,000 and 4.45 per 100,000 in 2021, respectively, and mortality rates of 0 and 0.02 per 100,000, respectively.

In the Low SDI region, the number of malaria cases and deaths in the under 5 age group peaked in 2010 and 2004, respectively, reaching 76,563,571 and 430,730. In contrast, the number of malaria cases and deaths in the same age group in the Middle and High SDI regions were significantly lower. Moreover, in the 5–9 and 10–14 age groups, the number of malaria cases and deaths were relatively low, regardless of the SDI category applied, including in the Low SDI region. Additionally, there was a notable increase in the number of deaths and mortality rate from malaria in 2020 and 2021 compared to 2019. (Fig. 3).

Fig. 3

Comparison of malaria case and mortality numbers across age groups in different SDI regions

The incidence and mortality rates of malaria in the under 5 age group were far higher than those in the 5–9 and 10–14 age groups in all regions. The incidence of malaria in all three age groups was higher than the Age-standardized rate, while the mortality rate was higher than the Age-standardized rate only in the under 5 age group (Fig. 4).

Fig. 4

Trends in malaria incidence and mortality rates across age groups globally and in various SDI regions from 1990 to 2021

From 1990 to 2015, the incidence and mortality rates of malaria in all three age groups in the five SDI regions showed a downward trend. However, from 2015 to 2021, the incidence of malaria in all three age groups in the Middle and Low-middle regions showed an upward trend, with the fastest increase in the under 5 age group in the Middle SDI region, with an average annual increase of 9.47% (95% CI, 7.99–10.95%). In addition, the mortality rate of malaria in the under 5 age group remained stable in all regions in 2015 (Fig. 5).

Fig. 5

EAPCs in malaria incidence and mortality rates across age groups globally and in various SDI regions from 1990 to 2021

Association between SDI and malaria incidence and mortality rates and their EAPCs from 1990 to 2021

As shown in Fig. 6, higher SDI correlated with a reduction in both malaria incidence and mortality rates, implying socio-demographic improvements could play a crucial role in mitigating the burden of malaria. Moreover, most of the low EAPC data points concentrate in countries with higher SDIs. Additionally, in countries with higher numbers of malaria cases and deaths, the negative EAPC values tend to drift closer to zero. This suggests that not only do countries with lower SDIs face higher incidences of malaria and associated mortality rates, but the decreasing trend in these rates also tends to be slower compared to countries with higher SDIs.

Fig. 6

Association between SDI and malaria incidence and mortality rates and their EAPCs from 1990 to 2021

Discussion

To the best of our knowledge, this study represents the first comprehensive effort to examine the global and national burden of malaria among children under 15 years of age from 1990 to 2021, with a particular focus on the diversities in malaria burden across different GBD and SDI regions. Our findings reveal a significant global burden of malaria among children under 15. In 2021, there were over 169 million cases and nearly 470,000 deaths in children under 15 worldwide. The study also highlights the stark disparities in the incidence and mortality rates of malaria across different countries and regions. For instance, Nigeria, the Democratic Republic of the Congo, and Uganda had the highest number of malaria cases and deaths, while countries like the Democratic People’s Republic of Korea and Venezuela, despite having relatively low incidence rates, saw an upward trend in malaria incidence and mortality rates from 1990 to 2021. Furthermore, our study underscores the severe burden of malaria in Sub-Saharan African regions and the disparities in malaria burden across different SDI regions. The Low SDI region had the highest incidence and mortality rates, despite seeing a downward trend from 1990 to 2021. Remarkably, the incidence of malaria in the Low-middle and Middle SDI regions showed an upward trend from 2015 to 2021. This trend is particularly concerning when coupled with the notable increase in the number of deaths and mortality rate from malaria in 2020 and 2021 compared to 2019. Finally, our findings suggest a correlation between higher SDI and reduction in malaria incidence and mortality rates, implying that socio-demographic improvements could play a crucial role in mitigating the burden of malaria. This study underscores the ongoing global burden of malaria, particularly among children under 15, and highlights the critical need for continued efforts to combat this disease, especially in regions with lower SDIs.

Our findings underscored the necessity for heightened attention towards the burden of malaria among children in certain countries and regions. The burden of malaria was particularly severe in Africa, with Nigeria, the Democratic Republic of the Congo, and Uganda reporting the highest number of malaria cases and fatalities. Additionally, countries such as the Democratic People’s Republic of Korea and Venezuela, despite having relatively low incidence rates, had observed an upward trend in both malaria incidence and mortality rates from 1990 to 2021. In Africa, the primary vectors of malaria are members of the Anopheles gambiae complex and the Anopheles funestus group [17]. Certain mosquito species are highly efficient malaria vectors in Africa due to their extended lifespan and increased human biting capacity, which play a significant role in malaria transmission and persistence [18, 19]. Understanding the role of these vectors helps contextualize the findings of our study, where we observe a continuing burden in regions with persistent vector populations despite ongoing malaria control efforts. Moreover, climatic changes, including rising temperatures and altered rainfall patterns, have extended the malaria season in numerous sub-Saharan African regions [20, 21]. Despite the confirmed efficacy of Insecticide-Treated Nets (ITNs) and Indoor Residual Spraying (IRS) in preventing mosquito bites and consequently malaria [19, 22], as of 2022, only 56% of the population in sub-Saharan Africa had access to ITNs within their households [1]. In the same year, a mere 1.8% of the population at risk in countries implementing IRS were protected, marking a decline from the 5.5% reported in 2010 [1]. These figures highlight the urgent need for expanding the reach of these proven malaria prevention measures.

Our study further reveals a concerning trend: global and regional malaria incidence rates in children have been rising since 2015, while malaria mortality rates have remained stable. This trend is in stark contrast to the malaria elimination goals set by the GTS. We also found that there was a notable increase in the number of deaths and mortality rate from malaria in 2020 and 2021 compared to 2019 in children under 15 years, further suggesting the profound impact of the COVID-19 pandemic, which disrupted health systems and services, as well as individual behaviors and mobility [23,24,25]. Despite concerted efforts by global partners to mitigate disruptions to malaria services, challenges still persisted, with essential health services reporting severe or partial disruptions [26,27,28]. Lessons learnt from these experiences underline the urgency to develop strategies that can simultaneously and effectively manage an ongoing endemic and potential future pandemic. Maintaining a robust and adaptable health system is crucial, as is a comprehensive plan that ensures continuous training of healthcare personnel, fair distribution of resources, and a decentralization of health services. Strengthening community resilience and self-reliance are also key considerations, ensuring adherence to procedures despite destabilization [29, 30].

Our study results further reveal a direct correlation between an increase in the SDI and a decline in both the incidence and mortality rates of malaria in children. Furthermore, countries with relatively higher SDI have exhibited faster declines in the incidence and mortality rates of childhood malaria. This correlation suggests a reciprocal relationship where enhanced socio-economic conditions can potentially fast-track the decline of disease prevalence. These findings align with the experiences of countries like China, which successfully eliminated malaria using the 1-3-7 strategy. This strategy, which focuses on rapid case reporting, investigation, and targeted public health actions, offers a useful model for malaria-endemic countries seeking to reduce the burden of malaria [31,32,33]. To complement these efforts, the global health community should prioritize strengthening the socio-economic conditions of malaria-endemic countries by investing in health systems, education, and living standards—key factors that drive SDI improvements and can expedite malaria control and eventual elimination.

Our study had several limitations. First, the use of yearly data from the GBD database may have led to misestimation of the disease burden in instances where original data were sparse or missing, as estimates were derived from models. Second, GBD data is typically reported at the national or regional level, which may not capture sub-national variations in disease incidence and mortality. Third, our study was limited to data available through 2021 and did not include the full duration of the COVID-19 pandemic, which may have impacted malaria incidence and mortality rates in subsequent years. Nevertheless, we observed an increase in malaria deaths during 2020 and 2021, revealing the impact of COVID-19 pandemic. This limitation can hinder the design of targeted interventions in high-risk areas. Despite these limitations, our findings still reflected the colossal global burden of childhood malaria, and they urged the formulation of national policies and international cooperation to reduce the health hazards posed by malaria.

In conclusion, our study represents the first comprehensive body of work examining the global and national burden of malaria among children under the age of 15 for a timespan between 1990 and 2021, unearthing the great global burdens of malaria, particularly pronounced in the demographic of children under the age of 15. Our findings underscore the need to improve on socio-economic conditions to speed up the alleviation of such burdens. Furthermore, our results call for targeted formulation of national policies and reinforcing international cooperation to mitigate the health hazards inflicted by malaria - particularly within regions with pronounced differences and low SDI. With concerted efforts at play, we are confident that the burden of malaria can be substantially alleviated, moving us closer to a world without malaria.