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Intermittent Preventive Treatment of Malaria in Pregnancy (IPTp2)

Intermittent preventive treatment with sulfadoxine-pyrimethamine of malaria in pregnancy (IPTp-SP) requires administration of a full therapeutic course of antimalarials given to pregnant women at routine antenatal care (ANC), regardless of infection status. IPTp reduces maternal malaria episodes, maternal and fetal anaemia, placental parasitaemia, low birth weight, and neonatal mortality1. Starting as early as possible in the second trimester, IPTp-SP is recommended for all pregnant women in malaria endemic areas at each scheduled antenatal care visit until the time of delivery, provided that the doses are given at least one month apart. SP should not be given during the first trimester of pregnancy; however, the last dose of IPTp-SP can be administered up to the time of delivery without safety concerns. IPTp should ideally be administered as directly observed therapy (DOT) of three tablets of SP.

Unit of interventionSecond dose of IPTp-SP (IPTp2)

FormulationSulfadoxine/pyrimethamine (500 mg/25 mg)

Dosage3 tablets of SP (1500 mg/75 mg)

Target populationPregnant women living in areas of moderate to high malaria transmission in Africa

For more information about how PSI is fighting malaria to improve health and save lives, visit our website at:
http://www.psi.org/health-area/malaria/

Model Overview

PSI’s IPTp2 impact model is based on the Lives Saved Tool (LiST), which estimates the impact of pregnant women receiving two or more doses of IPTp during pregnancy. LiST is used to estimate the number of deaths averted from increasing coverage of pregnant woman receiving at least a second dose of IPTp, representing the projected impact of administration of IPTp2. This number of deaths averted at the population level is translated to deaths averted per pregnant woman who has received a second dose of IPTp, using parameters such as the percent of the population exposed to P. falciparium malaria, baseline coverage of IPTp2, and the number of women pregnant in a year. Once we have deaths averted per administration of a second dose of IPTp, we apply data from the 2010 Global Burden of Disease study to estimate the corresponding number of DALYs averted.

Model Outputs (impact metrics)

Estimates of DALYs averted, deaths averted, CYPs provided, and unintended pregnancies averted represent the projected health impact of the intervention. It is projected because it has not been directly measured.

Examples based on distribution of IPTp-SP in Nigeria in 2015 Statement of modeled results, examples:

If 10,000 second doses of IPTp2 were administered in Nigeria in 2015, they would avert an estimated 9 deaths and 797 DALYs.

For more details about how PSI models the impact of IPTp2, see below.

Model Details

Step 1: Running a projection in the Lives Saved Tool (LiST)LiST is a multi-cause mortality model developed by Johns Hopkins Bloomberg School of Public Health that estimates the number of deaths averted (or lives saved) through the scale up of maternal and child health interventions.

PSI begins by running a projection in LiST for select countries. In this projection, coverage of at least two doses of IPTp is increased from the current, country-specific baseline to 100%. This coverage is increased to 100%. LiST then projects the number of deaths averted among pregnant women and children under five by this increased level of coverage.

Step 1 Output:
Number of additional deaths averted (or lives saved) among pregnant women and children under five if coverage of IPTp2 increased from baseline to 100%

Step 2: Estimating deaths averted per administration of IPTp2 among pregnant women and children under fivePSI uses the step 1 output (deaths averted at 100% coverage of at least two doses of IPTp) to estimate the number of deaths averted by one pregnant woman receiving a second dose of IPTp. To do this, we divide the number of deaths averted at 100% coverage by the number of pregnant women who would need to be administered a second dose of IPTp in order to reach 100% coverage of IPTp2.

PSI estimates the number of pregnant women who would need to be administered a second dose of IPTp in order to reach 100% coverage using a number of parameters, including the percent of the population exposed to P. falciparium malaria, baseline coverage of IPTp2, and the number of women pregnant in a year.

Step 2 Output:
Deaths averted coefficient for IPTp2

Step 3: Estimating DALYs averted per per IPTp2 among pregnant women and children under fiveA DALY (or disability adjusted life year) includes two components: years of life lost due to premature death (YLL) and years lived with disability (YLD). DALYs averted are in turn comprised of YLLs averted and YLDs averted or, put simply: death and disability that is prevented by PSI interventions.

To estimate YLLs averted per dose of IPTp2 among pregnant women and children under five, PSI first estimates the number of years of life lost per malaria death among each group in select countries. This is equal to the life expectancy at the average age of death from malaria in each group. Age specific life expectancy is taken from the 2010 Global Burden of Disease study (GBD 2010). The number of years of life lost per malaria death is then multiplied by the number of deaths averted per dose of IPTp2 among pregnant women and children under five separately (the deaths averted coefficient for each group), calculated in step 2 above for a selected country. This gives us the YLLs averted per dose of IPTp2.

To estimate YLDs averted per dose of IPTp2 among pregnant women and children under five, we use a YLD/YLL ratio, based on GBD 2010. This ratio represents the relative number of years lived with disability for every year lost due to death from malaria (calculated separately for each group). We apply this ratio to the number of YLLs averted per dose of IPTp2 to estimate the number of YLDs averted per dose of IPTp2 among pregnant women and children under five.

Finally, YLLs averted and YLDs averted are added together to estimate the number of DALYs averted per dose of IPTp2 among pregnant women and children under five.

Step 3 Output:
DALYs averted coefficient for IPTp2