Author/s: Nadine Nannan (Burden of Disease Research Unit, MRC) Date: November 2019
The infant mortality rate (IMR) is defined as the probability of dying within the first year of life, and refers to the number of babies under 12 months who die in a year, per 1,000 live births during the same year. Similarly, the under-five mortality rate (U5MR) is defined as the probability of a child dying between birth and the fifth birthday. The U5MR refers to the number of children under five years old who die in a year, per 1,000 live births in the same year. The neonatal mortality rate (NMR) is the probability of dying within the first 28 days of life, per 1,000 live births.
Dorrington RE, Bradshaw D, Laubscher R & Nannan, N (2019) Rapid Mortality Surveillance Report 2017. Cape Town: South African Medical Research Council.
The infant and under-five mortality rates are key indicators of heath and development. They are associated with a broad range of bio-demographic, health and environmental factors which are not only important determinants of child health but are also informative about the health status of the broader population.
The infant mortality rate (IMR) is defined as the probability of dying within the first year of life and refers to the number of babies under 12 months who die in a year per 1,000 live births during the same year. Similarly, the under-five mortality rate (U5MR) is defined as the probability of a child dying between birth and their fifth birthday. The U5MR refers to the number of children under five years old who die in a year per 1,000 live births in the same year.
This information is ideally obtained from vital registration systems. However, like in many middle- and lower-income countries, the under-reporting of births and deaths renders the South African system inadequate for monitoring purposes. South Africa is therefore reliant on alternative methods, such as survey and census data, to measure child mortality. Despite several surveys which should have provided information to monitor progress, the lack of reliable data since 2000 led to considerable uncertainty around the level of childhood mortality for a prolonged period. However, the second South Africa National Burden of Disease Study has produced national and provincial infant and under-five mortality trends from 1997 up until 2012.1
An alternative approach to monitoring age-specific mortality nationally since 2009 is the rapid mortality surveillance system (RMS) based on the deaths recorded on the population register by the Department of Home Affairs.2 The RMS data have been recommended by the Health Data Advisory and Co-ordinating Committee because corrections have been made for known biases. In other words, the indicators shown in the table are nationally representative. The RMS reports vital registration data adjusted for under-reporting which allow evaluation of annual trends. They suggest the IMR peaked in 2003 when it was 53 per 1,000 and decreased to 23 per 1,000 in 2017. During the same period the U5MR decreased from 81 per 1,000 to 32 per 1,000.
The neonatal mortality rate (NMR) is the probability of dying within the first 28 days of life per 1,000 live births. The NMR was 12 deaths per 1,000 live births in 2017. Estimates of the NMR are derived directly from vital registration data (i.e. registered deaths and births without adjustment for incompleteness) up to 2013, and from 2013 onwards the estimates were derived directly from neonatal deaths and live births recorded in the District Health Information System.
The South African Health and Demographic Survey also reports child mortality rates. After a long gap (since 2003) the SADHS was conducted in 2016.3 For the period 2012 – 2016, the RMS estimated a slightly higher overall under-five mortality rate than the SADHS – 42 versus 39 per 1,000 live births. However, the SADHS infant mortality rate (IMR) for recent years is much higher than the IMR from the RMS (35 versus 27 per 1,000 live births for the period 2012 – 2016). The SADHS estimates are likely to be too high because its neonatal mortality rate is too high.
1 These profiles can be seen at: http://www.mrc.ac.za/bod/reports.htm
2 Bradshaw D, Dorrington RE, Nannan N & Laubscher R (2014) Rapid Mortality Surveillance Report 2013. Cape Town: Medical Research Council.
3 National Department of Health, Statistics South Africa, South African Medical Research Council and ICF (2017) South African Demographic & Health Survey 2016: Key Indicators. Pretoria and Rockville, Maryland: NDOH, Stats SA, SAMRC & ICF.