A district-level demographic survey was conducted in Mopeia to map, identify and characterize households in the area, as well as to determine the size and structure of the population. The key result of the demographic survey was the creation of the study clusters, which were built based on the population of children under five years of age. In addition, the demographic survey was crucial to plan the implementation of all field activities related to the clinical trial and the other BOHEMIA work packages (including estimation of the amount of drug, the number of field staff). These data were used to draw the randomization and sampling schemes of the cRCT, as well as to identify information relevant to the study (eg, cattle ownership or lack thereof). Finally, the mapping of all households in the district made it possible to calculate the proportion of households reached by the cRCT.
The reconnaissance activity was a key starting point when working in a place as remote as Mopeia. It served to better understand the size of the district, accessibility and 3G in the villages of the district, which allowed effective planning of all other field activities. A total of 27,928 households (including those that did not participate) were enumerated in the study. The majority of households in the district (25,550, 91.5%) were mapped via their GPS coordinates, identified with a household ID, and a household member responded to the demographic survey. A total of 546 households (2%) refused to participate in the study or had no one present after two attempts, indicating the success of community participation and demonstrating the importance of this type of activity in studies of this nature. .
The results of the demographic survey indicate that living conditions in Mopeia are poor and often inadequate for the heavy rains and cyclones that affect the district. Access to electricity is low. According to the National Malaria Survey (Inquérito Nacional sobre Indicadores de Malária em Moçambique 2018, IMM), only 13.3% of households in Zambezia have electricity, which is close to the 11.7% identified in the study. National definitions of improved water sources include those that are physically protected from external contamination, such as piped water, fountains, protected wells, protected wells with hand pumps, rainwater, bottled water, and water from a tanker truck. [3]. Any water from unprotected wells or surface water (eg, lakes, rivers, ponds) is considered unimproved. Based on these indicators, the IMM reports that 54.4% of households in Zambezia have access to improved water systems, while the study identified 66.1% in Mopeia (considering “Unknown” and “Other” as unenhanced sources). According to the WHO/UNICEF monitoring program [19], access to basic drinking water means getting water from an improved source taking less than 30 minutes total to bring it. A total of 45.6% of households in Mopeia reported having access to water between 10 and 30 min and 31.8% less than 10, but 17.7% reported taking between 30 and 60 min, and 4.8% They reported taking over an hour. These results show that not all households in Mopeia have access to basic water services, which can lead to poor hygiene conditions and the spread of infectious diseases.
In rural areas of low-income countries, livestock ownership can represent a significant percentage of the family economy, since the animals can be sold or used for self-consumption or physical labor. [20]. However, only 7.9% of households in Mopeia reported owning pigs and/or cattle (other livestock were not asked). Of the households that owned pigs and/or cattle, the majority owned pigs, and very few households owned cattle. This could be indicative of the poverty rates in Mopeia or that families own other livestock such as goats, chickens.
Mopeia is a high burden area for malaria, as a recent study indicated a prevalence of 62% to 75% in children under five years of age at the peak of the rainy season. [15]. However, the district has great LLINS access, coverage, and turnover as shown by the demographic survey. 90.7% of households in Mopeia district had at least one LLIN, which is higher than what the IMM reported for Zambezia province in 2018, 81% and 54.1% of households in Mopeia have universal LLIN coverage, defined as one LLIN for two household members. The IRS coverage reported in 2018 for Zambezia was 23.5% and the study recorded 71.1% in Mopeia in 2020. Having such good coverage of vector control tools and yet the high burden of malaria made Mopeia a suitable district to evaluate a complementary vector control strategy. .
In terms of population, 131,818 people were registered, a figure lower than the INE estimates, but the study ignored people who lived in households that refused or in which household members were absent twice. The population structure in Mopeia is typical of a sub-Saharan country, in which the largest age group is the youngest children, and the shape of the pyramid narrows as the age of the population increases. There are a little more women than men and there are only 23.1%. female heads of household, which shows that the household-based structures in Mopeia are mostly dominated by men.
The age structure of death in Mopeia is completely biased towards the young population. Of the total deaths reported in the last 12 months, the largest number occurred in children under 5 years of age (43.6%). This is in line with the 2019 National Mortality Surveillance for Action (COMSA) results, which reported that 37% of deaths in Zambezia province were among children under five years of age. [21]. Furthermore, most of the deaths reported in Mopeia occurred during the first year of life. This demographic survey did not inquire about the cause of death, but according to previous reports from the national survey on causes of death (Inquerito Nacional sobre Causas de Mortalidade), malaria is the leading cause of death for children under five in Zambezia, with almost 40% of deaths attributable to this disease [22]. Other major causes of death reported among children in Zambezia are HIV, pneumonia, and diarrheal diseases, which show a high burden of communicable diseases. Finally, most of the deaths occurred at home, which could be due to poor access to medical care and under-resourced health services. Although not asked in the demographic survey, it could also be due to poor health-seeking behavior. A key consequence of this was the need for enhanced active surveillance of serious adverse events and adverse events at the community level during the cRCT.
The main limitation of the study is the size and depth of the survey, since it did not allow detailed collection of individual data. All information was collected at the household level, with no person-level data other than basic household member demographics. Another limitation is that the study did not use satellite imagery to map and identify the work area prior to field operations, which has been used previously in similar interventions, such as IRS campaigns. [23, 24]. While this strategy has proven to be quick and inexpensive, and has helped ensure that all households in an area are included, this demographic survey was conducted in a very rural, sparse, and remote area with dense vegetation, making it that it is very difficult to differentiate between the different types of constructions and to distinguish them among the vegetation. Other limitations of the study arise from the difficulty of working in a remote area like Mopeia. The team faced accessibility issues that significantly slowed down field activities and several homes were destroyed or abandoned due to harsh weather conditions. Additionally, data collection in areas without 3G connectivity represented a major operational challenge. Overall, this experience highlighted the difficulties encountered at the time of MDA or any community intervention that requires large-scale field deployment.
