This study identified a significant decrease in severe anaemia and ACCM in DRC from 2007 to 2013–2014. This downward trend is most likely driven by household ownership of ITNs and use of ITNs among children under five. During this same period, there was a significant increase in financial investments by the country and its partners, focused on the scale-up of malaria control interventions, particularly vector control, from 18 million USD in 2007 to 175 million USD in 2015 [23, 24]. The NMCP implemented three ITN mass distribution campaigns across the country from 2009 to 2013, with a plan to distribute 1–3 ITNs per household or about 35 million ITNs total [25, 26]. This strategy and investments led to the significant increase in household ITN ownership and use among children under five. DRC nearly achieved its ITN ownership coverage target of 80%. ITN ownership and use targets are often difficult to achieve. In a study of 22 sub-Saharan African countries, only 4 achieved their household ITN ownership targets, and none achieved their ITN use among children under five targets . Despite not meeting the targets, the intervention coverage in DRC reached a level mature enough to have a public health impact.
The results show a clear pattern, which can be observed through the changes across the 11 provinces. The subnational analysis revealed an overall increase in ITN ownership and a significant decrease in ACCM and severe anaemia, but most importantly, some of the provinces with the largest improvements in coverage of ITN ownership and use also reported the largest decrease in ACCM. A finding reflected in a similar assessment showed a strong correlation between a high level of ITN use and the protective effect against malaria among children under five in DRC . The implementation of routine distribution of ITNs through antenatal clinics and EPI services, with a focus on younger children, may have resulted in the more pronounced decline in child mortality among children aged 6–23 months, compared to those aged 24–59 months. This is significant because children aged 6–23 months are more susceptible to malaria mortality . Similar results were found by Dolan et al., who identified a 41% reduction in ACCM among children living in rural areas due to ITN distribution campaigns that targeted the highest risk areas for malaria in DRC . Furthermore, this observation is consistent with other studies in sub-Saharan Africa that found an association between an increase in ITN ownership and a decline in ACCM and severe anaemia [31–33].
The results of the Kaplan-Meier survival probability analysis and Cox proportional hazards regressions both indicated an improved probability of survival among children under five post-intervention scale-up, compared to pre-intervention scale-up, which further supports the association between the increase in ITN coverage and decrease in ACCM. These methods have been used in similar studies assessing ITN effectiveness in reducing child mortality .
In addition to the scale-up of ITNs, the NMCP planned to implement several interventions during the evaluation period, however, the results were not as promising. The trends analysis revealed that access to ACTs was still very low. In addition, low adherence to treatment policies and use of non-ACTs were prevalent across the country . The deployment of IRS across the country has been limited to one province due to funding and technical and logistical challenges . The scale-up of IPTp across the country has not reached a comparable scale to ITNs . A study conducted in 2013 found that only 20% of public health facilities in DRC were stocking sulfadoxine-pyrimethamine for IPTp . The unmet goals for these interventions strengthen the plausible attribution of ITN ownership and ITN use to the observed decrease in ACCM.
To further investigate potential factors that may have contributed to the decline in ACCM, the contextual factor analysis indicated only a modest improvement in living conditions, sanitation, and maternal and child health indicators, such as nutritional status, vaccination status, exclusive breastfeeding, and access to water and improved toilets [2, 37, 38]. There were also no substantial changes in climate, rainfall, and temperature between 2005 and 2014 that may have affected the national mortality trend. Based on the analysis of these key factors known to affect malaria incidence, it is unlikely that these non-malaria contextual factors can explain a large proportion of the 30% reduction of ACCM [39, 40].
Overall, these results support the conclusion that the increase in household ITN ownership and increase in ITN use among children under five have contributed to the observed decrease in ACCM and severe anaemia from 2005 to 2014 in DRC. This study provides an assessment of the intervention coverage achieved and describes malaria-related morbidity and mortality rates up to 2014 in DRC. These results also provide baseline data that will be important for the measurement of the imminent progress that will be achieved at the end of the current 2016–2020 NMSP and may inform the decision-making of the NMCP and its partners as they transition to a new NMSP. Further research will be needed to fully understand how an increase in ITN ownership and use results in decreased ACCM and severe anaemia. However, DRC has made significant progress since 2005 in increasing intervention coverage and decreasing the burden of malaria on the population.
Limitations of the Study
The use of secondary data from the DHS 2007 and DHS 2013–2014 limited this study to the variables that were collected in those surveys. No further primary data were collected. The difference in methodology between national surveys precluded the inclusion of the 2010 and 2017–2018 DRC Multiple Indicator Cluster Survey, which may have provided another data point to help elucidate the effects of DRC’s malaria control intervention scale-up.