25 Years of CISM: Why Successful Research Depends Entirely on Demographic Surveillance

[This text is written by Arsénio Nhancolo, Management and Data Analysis Manager (Interim) at Manhiça Health Research Centre (CISM), and Charfudin Sacoor, Head of Demography at CISM. This blog post is a one of a series of articles to commemorate the 25th anniversary of CISM].

Imagine you become ill and you go to a health centre in Maputo, Mozambique. After several tests, you are diagnosed with an infectious disease that is highly contagious. The doctors urgently need to contact the people you live with to find out if they have been infected and follow them up. In the city of Maputo, it is not easy to get this information. However, if the same thing were to happen about 80 km away, in Manhiça district, a rural part of Maputo province, we could use a database to locate the patient’s home and identify the people living under the same roof. The database also contains the telephone number of a person responsible for each home who, if necessary, can be contacted for disease prevention purposes.

Twenty-five years ago, when the Manhiça Health Research Centre (CISM) was founded with the aim of conducting biomedical research in a rural area of southern Mozambique, it was essential to have a demographic surveillance platform capable of offsetting the limitations that characterised—and still characterise—common demographic sources such as censuses and civil registration systems in less developed countries. The creation of such a platform was essential in order to conduct cutting-edge biomedical research, particularly studies requiring regular follow-up of participants.

Twenty-five years ago, when the CISM was founded, it was essential to have a demographic surveillance platform capable of offsetting the limitations that characterised—and still characterise—common demographic sources such as censuses and civil registration systems in less developed countries

General population censuses in Mozambique are conducted every 10 years. The data they produce quickly become outdated and the institutions responsible for the censuses never provide personal data on the population. In other words, census data would not allow us to say, This is Maria, she is 21 years old, she lives with João in house number 5, she has two babies aged 24 months and 8 months, and she is in the first trimester of her third pregnancy . And then there is the fact that data used in studies have to be updated regularly, because people are constantly being born, dying or migrating. But the data from the general population census are not available to end users until two years after the census was completed, making them out of date from the start.

A health and demographic surveillance system is a platform that facilitates research and the assessment of public health interventions and provides accurate estimates of vital demographic events within a well-defined territory with a well-identified population. These systems have proved invaluable for evaluating health interventions, particularly in sub-Saharan Africa, where many countries lack complete and up-to-date demographic data. Setting up such a system involves counting the entire population of a given area. Each individual is registered in the system and given a permanent identification number.

Entrance to the Demography area of the CISM, in Manhiça (Mozambique).

In addition, each person’s relationship to the head of household, date of birth, sex, education level, and other relevant demographic and health data must also be recorded. These demographic and health data are necessary for health planning and evaluation at the district, regional and national levels, nationwide policy formulation, and the planning of large-scale clinical trials.

We believe that the success of CISM’s research is intrinsically linked to surveillance efforts in the district, which allow for demographic data to be collected and participants to be followed up during studies, both of which are essential for quality research.

We believe that the success of CISM’s research is intrinsically linked to surveillance efforts in the district, which allow for demographic data to be collected and participants to be followed up during studies, both of which are essential for quality research.

To conduct a study, we need to know how many people there are in a particular geographical area, who they are and where they live. We also need demographic data and indicators to measure the impact of different interventions, to locate participants, to observe demographic trends in the population and to produce accurate maps of disease distribution in the study area, among other things.

This demographic surveillance is complemented by hospital morbidity surveillance, wherein all cases arriving at hospital units are linked to the person’s demographic identification number. By tracking the patients that arrive at hospital units in this way, we are able to monitor the health status of the population. This linkage greatly increases the potential of our surveillance system and, in general, CISM’s ability to conduct very high-quality studies, which we would not have been able to do otherwise.

CISM Demography team in 2003.

From the outset, this was the main potential of the basic census of Manhiça district, which in 1996 was conducted in specific areas. Until 2013, the census area covered 500 km². In 2014, it was expanded to include the entire district, covering 2,380 km² inhabited by 208,000 people. Years later, thanks to the experience gained in Manhiça, similar censuses were carried out in other nearby areas, such as Magude in Maputo province (2015), within the framework of the Mozambican Alliance Towards Elimination of Malaria (MALTEM), and in Mopeia in Zambézia province (2017), within the framework of the BOHEMIA project.

In October of this year, as part of the CHAMPS project, we began a census in Quelimane district of Zambézia province, where we are identifying 350,000 inhabitants. In addition, CISM has supported the efforts of Mozambique’s National Institute of Health to implement two health and demographic surveillance systems, one in Chikwe district in Gaza province and the other in Bairro Polana Canico in the city of Maputo. CISM has also supported the creation or improvement of several other research centres in sub-Saharan African countries, including South Africa, Mali and Sierra Leone.

Map of Manhiça district, Mozambique, showing the old surveillance area (light orange), the new area (yellow) and the spatial distribution of dwellings.

Main Contributions Over the Past 25 Years

Over the past 25 years, the geographic and demographic monitoring platform has proved to be one of CISM’s greatest assets. Virtually all of the institution’s notable milestones are linked in some way to the great contributions of this platform.

To cite a few examples:

• Phase III clinical trial of the malaria vaccine: The quality of the trial and the follow-up of participants were made possible by the existence of the platform.
• First article on causes of death published in Mozambique: The demographic information on Manhiça enabled the publication of this article by Dr. Jahit Sacarlal.
• Publications in international peer-reviewed journals on Manhiça’s progress towards the United Nations Millennium Development Goals (MDGs): Although data from Manhiça cannot be extrapolated to the entire country, we were able to verify aspects such as the decrease in infant mortality—particularly Manhiça’s progress in this area with respect to the MDGs—and publish our findings in journals and reports.
• High level of acceptability of the surveillance system: We have managed to involve the population of Manhiça district in this “research” process. After 25 years, the community’s commitment to CISM’s study activities is clear, as our acceptability rate remains very high.
• Training and education: Drawing on our experience with our own demographic platform, we have been able to assist in the training of people such as students of public health and provide technical support to various centres in Mozambique and elsewhere.
• Manhiça’s demographic surveillance system has become internationally renowned: Even initiatives with a years-long track record have learned from our experience.
• We have published articles showing that demographic surveillance systems have more detail and are able to record demographic trends that make sense within their specific geographical areas, as compared to other sources such as censuses and demographic health surveys.

New Concerns and Challenges Have Emerged Over the Years

Back in 1996, we started out by addressing basic questions related to malaria. Over time, however, we began posing, adapting and incorporating new questions in response to our surroundings. For example, with the emergence of COVID-19, we recently had to shift gears and address questions and dynamics related to this new health issue. A few years ago, we decided that CISM had to make a strong commitment to addressing neglected diseases, especially with regard to helminths, so we incorporated this issue into our surveillance system.

Back in 1996, we started out by addressing basic questions related to malaria. Over time, however, we began posing, adapting and incorporating new questions in response to our surroundings

As we have evolved, we have raised new questions. Simply calculating mortality, fertility and migration trends is no longer sufficient:

• Why do children from the same neighbourhood have different levels of growth or experience different levels of impact in terms of malaria transmission, even though they are all Mozambicans of the same age, living in the same place? Why do some have malaria and others do not?
• Why do people migrate? What prompts a person leave home and migrate to South Africa?

With our system, we were able to quantify migration. We knew, for example, that a person had left a particular home and gone to South Africa; this enabled us to determine precise numerators and denominators for all of the necessary calculations in the study. However, we were unable to answer the question of why people came to Manhiça and then left.

Data collection for the mass administration of antimalarial drugs campaign in Magude. Year 2016.

In order to answer these questions, we needed, first and foremost, to restructure our data collection system. This was a complex undertaking that required financial support and human resources to manage the new tools.

Conducting surveys in a rural setting is no simple task. The low literacy rate complicates the implementation of surveillance measures and is accompanied by many other challenges, not least the immediate concerns of rural life in a country like Mozambique.

These people do not understand the concept of a survey and will wonder what you are doing there if you are not going to address their immediate concerns. In many cases, they may have nothing to feed their families on the day we pay a visit to their homes, or they may have stayed home from working the fields in order to answer our questions. To make matters worse, if we tell them that we are working to eliminate malaria, mosquitoes will still be buzzing around the next day and their children will still have malaria. We ask them to sign an informed consent form, but in their culture, having to sign documents is a sure sign that trouble is coming. Another difficult-to-grasp concept, for example, is that of neonatal mortality, especially when it occurs in the first 24 hours. For many Mozambican women, if a baby doesn’t make it home, it is considered stillborn and is barely spoken of.

Conducting surveys in a rural setting is no simple task. These people do not understand the concept of a survey and will wonder what you are doing there if you are not going to address their immediate concerns. In many cases, they may have nothing to feed their families on the day we pay a visit to their homes

What Does the Future Hold?

The more questions we address and the more time we spend in the area, the higher the expectations of the community. It is important to note that we are not merely studying the health problems of Manhiça itself; by taking Manhiça as an example, we are also learning about the problems of the sub-Saharan African population generally.

Our surveillance of demographic events currently encompasses the entire population, but surveillance of morbidity is limited to children under 15 years of age. We believe it is necessary to reflect on the inclusion of adult morbidity.

It is important to note that we are not merely studying the health problems of Manhiça itself; by taking Manhiça as an example, we are also learning about the problems of the sub-Saharan African population generally

To what extent will we remain neutral in order to strictly comply with our mandate? Shouldn’t we try to design community support strategies to solve some of the problems that undoubtedly affect health? It is difficult to just ask questions if we do not offer solutions to specific day-to-day problems.

We believe it is fair to say, very humbly, that our demographic surveillance platform has been a driver of research in Manhiça over the past 25 years.