Caregiver exposure to malaria social and behaviour change messages can improve bed net use among children in an endemic country: secondary analysis of the 2015 Nigeria Malaria Indicator Survey

Background To reduce the malaria burden in Nigeria, the National Malaria Strategic Plan (NMSP) 2014‒2020 calls for the scale-up of prevention and treatment interventions, including social and behaviour change (SBC). SBC interventions can increase awareness and improve the demand for and uptake of malaria interventions. However, there is limited evidence supporting the implementation of SBC interventions to improve key malaria behaviours, such as insecticide-treated bed net (ITN) use, among children in Nigeria. Methods Using data from 2015 Nigeria Malaria Indicator Survey, this study used multiple logistic regression to assess the relationship between caregiver exposure to malaria messages and ITN use among children under five. Results Caregiver exposure to ITN-related messages was significantly associated with ITN use among children under five (odds ratio [OR] = 1.63, p < 0.001). Conclusions The results suggest that caregiver exposure to topic-specific SBC messages improves the use of ITNs among children. Given these results, Nigeria should strive to scale up SBC interventions to help increase ITN use among children in line with the objectives of the NMSP. Further evidence is needed to determine which SBC interventions are the most effective and scalable in Nigeria.


Background
Malaria is a major health issue in Nigeria. In 2016, there were an estimated 57.3 million malaria cases and 100,700 malaria deaths [1]. In 2015, approximately 21% of deaths, 60% of outpatient visits, and 30% of hospitalizations of children under five were caused by malaria [2]. To address the malaria burden, Nigeria is expanding key malaria interventions. The country's National Malaria Strategic Plan (NMSP) 2014-2020 aims to transition the focus from malaria control to malaria elimination, with the goal of achieving pre-elimination status and reducing malaria-related deaths to zero by 2020 [3]. To reach this goal, the strategic plan calls for the scale-up of prevention strategies, including universal long-lasting insecticide-treated net (LLIN) coverage.
Although coverage of key malaria interventions is improving, large gaps remain, especially among children under five, and further effort is needed to reach the country's 2020 targets [4]. According to the 2015 Nigeria

Open Access
Malaria Journal *Correspondence: Kirsten.Zalisk@icf.com 1 MEASURE Evaluation, ICF, 530 Gaither Road, Suite 500, Rockville, MD 20850, USA Full list of author information is available at the end of the article Malaria Indicator Survey (NMIS), approximately twothirds of households in Nigeria own at least one insecticide-treated net (ITN), but only 44% of children under five used an ITN the night before the survey (2015 NMSP target: 50%) [4]. Notably, more than 90% of ITNs are obtained free-of-charge through campaigns or through regular distribution during antenatal care or child immunization visits or at government health facilities in Nigeria [4].
Social and behaviour change (SBC) interventions are also an important component of Nigeria's NMSP and are seen as integral to achieving its intervention coverage targets by creating awareness and improving demand for and the uptake of prevention and treatment interventions. Malaria SBC interventions are widely employed in the country. For example, mass ITN distributions are accompanied by SBC messaging [5,6]. Programme implementers have used SBC interventions that involve national mass media messaging, interpersonal communication at the community level, and multi-channel approaches in their programme areas [7][8][9].

Study design
This cross-sectional study was a secondary analysis of 2015 NMIS data to assess the relationship between mother or caregiver (hereafter referred to as "caregiver") exposure to malaria SBC messages and ITN use among children under five.

Data
The 2015 NMIS used a cluster-based sampling design to select a nationally representative sample of more than 8000 households from 329 clusters throughout the country. A total of 7745 selected households agreed to participate in the survey (response rate: 98.8%). In each household, all women between the ages of 15 and 49 were eligible to be interviewed, and 8034 women agreed to participate (response rate: 99.1%). Survey fieldwork took place in October and November 2015, immediately following the end of the rainy season, during the period when malaria transmission peaks. Further details on the survey methodology are provided in the survey final report [4].

Data analysis
The authors used multiple logistic regression [30,31] to assess the relationship between caregiver exposure to at least one ITN-specific malaria message and ITN use among children under five. The outcome variable was children under five who slept under an ITN the night preceding the survey. The exposure variable was caregivers of children under five who were exposed to at least one ITNrelated message in the 6 months preceding the survey. Exposure to a message related to ITN use was defined as recall of at least one of the following two messages in the past 6 months: "sleeping inside a mosquito net is important" or "who should sleep inside a mosquito net".
The model adjusted for select variables that could potentially confound the relationship between the outcome and exposure variables. These covariates were age and sex of the child, caregiver's educational attainment, place of residence (i.e., urban or rural), region of the country, household wealth quintile [32], household ownership of a radio, household ownership of a television, and adequate number of ITNs in household-defined as the household owning at least one ITN per every two household members. The model was restricted to include one randomly selected eligible child per household to avoid cluster effects. The model was also restricted to include only children who slept in the household the night preceding the survey in households that owned at least one ITN. All analyses were done using Stata version 14 (StataCorp LLC, College Station, Texas, USA).

ITN use among children under five by background characteristics
Insecticide-treated net use among children under five did not vary by child sex, child age, or household ownership of a radio, but it did vary by a number of characteristics. ITN use increased as the wealth quintile decreased, with 40.5% of children under five having used an ITN in the highest wealth quintile, and 69.9% of children under five having used an ITN in the lowest wealth quintile (p < 0.0001). ITN use was higher among children who lived in households with an adequate number of ITNs (69.1%, p < 0.0001), among children whose caregivers were exposed to an ITN-related message (55.9%, p = 0.0004), among children from rural areas (62.0%, p = 0.0005), among children from the North Central (60.7%), North East (61.0%) and North West (70.5%) regions (p < 0.0001), and among children living in households that did not own a television (66.3%, p < 0.0001) ( Table 1).

Caregiver exposure to ITN messages and ITN use among children under five
The odds of ITN use were 1.6 times higher among children whose caregivers were exposed to at least one ITN message in the 6 months preceding the survey compared with children whose caregivers were not exposed to at least one ITN message in the 6 months preceding the survey (odds ratio [OR] = 1.63, p < 0.001). ITN use was significantly associated with residence, wealth quintile, region, adequate number of ITNs in household, and household ownership of a radio. Significant associations were not found between ITN use and sex or age of the child, caregiver's educational attainment, or household ownership of a television ( Table 2).

Discussion
This study assessed the relationship between caregiver exposure to malaria SBC messages and ITN use among children under five. The results suggest that caregiver exposure to ITN-related messages in the preceding 6 months has a positive effect on ITN use among children under five. Approximately two-thirds of households in Nigeria own at least one ITN, of which the majority are obtained through distribution campaigns [4] that usually include an SBC intervention to encourage regular, consistent, and proper use of the nets [5,6]. ITNs are also obtained during antenatal care or child immunization visits, which offer opportunities for healthcare providers to share SBC messages specifically with caregivers of young children to ensure that they understand the benefits of their children sleeping under an ITN. The two most common sources of malaria messages are the radio and television [4], which can supplement messages provided during distribution campaigns and healthcare visits.
Other studies assessing the relationship between exposure to a malaria SBC intervention or message and ITN use among children have shown mixed results [11,13,16,19]. For example, studies in Cameroon and Ghana found significant positive associations between caregiver exposure to malaria messages and ITN use in children [13,19], but two studies in Zambia did not find a significant association between caregiver exposure to SBC interventions and ITN use among children [11,16]. Although a limited number of studies explore ITN use among children in relation to caregiver exposure to relevant SBC messages, more studies look at ITN use among other household members in relation to exposure to SBC messages. In other parts of sub-Saharan Africa, studies show that SBC exposure has positive effects on ITN use in a variety of populations, including women of reproductive age [10], mothers of children under five [15], and all household members [14,18]. Moreover, two studies conducted in Nigeria show that SBC exposure had positive effects on ITN use among household heads and their spouses [6] and all household members [5].
Our results suggest that SBC interventions can play an important role in improving ITN use among children under five. Given these findings and the low coverage of malaria SBC message exposure in the country, Nigeria should strive to scale up SBC interventions as the country seeks to achieve universal LLIN coverage. Meeting this intervention coverage target by 2020 requires improved ITN use among children. Although the country has made progress in improving malaria intervention coverage over the past decade, current coverage is behind 2015 targets, and large gaps remain to achieve the 2020 targets. Among women of reproductive age, only 36% recalled exposure to messages about malaria in the 6 months preceding the survey [4], even though SBC efforts to support key malaria prevention and management interventions have been ongoing [3,7,8]. Furthermore, of those women who recalled hearing any messages, fewer than half recalled messages related to ITNs. The most commonly recalled message was that sleeping inside a mosquito net is important (39%), but only 9% recalled messages about who should sleep inside a mosquito net [4].
The Federal Ministry of Health has an advocacy, communication, and social mobilization (ACSM) guide, which was updated in 2014 [33,34], to help standardize ACSM programming, of which SBC messaging is an integral component, and to ensure that ACSM activities align with the NMSP. The NMSP notes that more evidence-based, culturally sensitive, and suitable SBC materials are needed, but it also states that the most effective SBC strategies (e.g., music, drama, sports, competitions) for improving the uptake of malaria interventions must still be determined [3]. In assessing possible SBC interventions, it will be important to consider the context in which they will be implemented. For example, mass ITN distributions are obvious opportunities on which to capitalize for promoting ITN use, but how is ITN messaging best conveyed if there are not mass ITN distributions? More evidence is needed to better understand and inform scaling up such interventions concurrently with prevention and treatment interventions in the country, especially in light of the substantial investments being made in SBC interventions and the country's important push toward malaria elimination.

Limitations
Due to the lack of variation in recall of ITN use messages, a valid exposure index could not be created to examine a dose-response relationship between SBC exposure and ITN use. In addition, the NMIS did not capture the intensity or source of specific messages. The study was limited to assessing the relationship between the outcome of interest and select individual and household-level background characteristics available in the dataset, which taken from a secondary data source. There was also a potential recall bias among survey respondents because the recall period for having heard messages related to ITN use was 6 months.

Conclusions
This study suggests that caregiver exposure to ITNrelated malaria messages improves the use of ITNs among children under five. These positive effects can be leveraged to advocate for malaria SBC interventions as an integral part of Nigeria's strategy to scale up prevention and treatment intervention coverage to meet its 2020 targets. However, more evidence is needed on the impact of specific SBC interventions to determine which are the most effective and scalable in Nigeria.