Yukari Manabe and colleagues evaluate the cost-effectiveness and budget impact of antenatal syphilis screening for 43 countries in sub-Saharan Africa and estimate the impact of universal screening on averted stillbirths, neonatal deaths, congenital syphilis, and DALYs.
Please see later in the article for the Editors' Summary
Untreated syphilis in pregnancy is associated with adverse clinical outcomes for the infant. Most syphilis infections occur in sub-Saharan Africa (SSA), where coverage of antenatal screening for syphilis is inadequate. Recently introduced point-of-care syphilis tests have high accuracy and demonstrate potential to increase coverage of antenatal screening. However, country-specific cost-effectiveness data for these tests are limited. The objective of this analysis was to evaluate the cost-effectiveness and budget impact of antenatal syphilis screening for 43 countries in SSA and estimate the impact of universal screening on stillbirths, neonatal deaths, congenital syphilis, and disability-adjusted life years (DALYs) averted.
Methods and Findings
The decision analytic model reflected the perspective of the national health care system and was based on the sensitivity (86%) and specificity (99%) reported for the immunochromatographic strip (ICS) test. Clinical outcomes of infants born to syphilis-infected mothers on the end points of stillbirth, neonatal death, and congenital syphilis were obtained from published sources. Treatment was assumed to consist of three injections of benzathine penicillin. Country-specific inputs included the antenatal prevalence of syphilis, annual number of live births, proportion of women with at least one antenatal care visit, per capita gross national income, and estimated hourly nurse wages. In all 43 sub-Saharan African countries analyzed, syphilis screening is highly cost-effective, with an average cost/DALY averted of US$11 (range: US$2–US$48). Screening remains highly cost-effective even if the average prevalence falls from the current rate of 3.1% (range: 0.6%–14.0%) to 0.038% (range: 0.002%–0.113%). Universal antenatal screening of pregnant women in clinics may reduce the annual number of stillbirths by up to 64,000, neonatal deaths by up to 25,000, and annual incidence of congenital syphilis by up to 32,000, and avert up to 2.6 million DALYs at an estimated annual direct medical cost of US$20.8 million.
Use of ICS tests for antenatal syphilis screening is highly cost-effective in SSA. Substantial reduction in DALYs can be achieved at a relatively modest budget impact. In SSA, antenatal programs should expand access to syphilis screening using the ICS test.
Please see later in the article for the Editors' Summary
Syphilis is a sexually transmitted infection caused by a bacterium called Treponema pallidum. In many countries, the screening and treatment program for syphilis in pregnancy is inadequate, leading to babies being affected. It is estimated that between 2.5% and 17% of pregnant women in sub-Saharan Africa are infected with syphilis; recent estimates suggest that more than 535,000 pregnancies occur in women with active syphilis each year. Maternal syphilis in pregnancy has been estimated to cause approximately half a million adverse outcomes in babies, including stillbirths, neonatal deaths, preterm or low-birth-weight babies, and congenital infections. If a pregnant woman is tested, and given penicillin if positive, then many of these harmful outcomes can be avoided. The best time to screen and treat is in the first half of pregnancy.
Until recently, tests for syphilis were done in a laboratory as an enzyme immunoassay, requiring technical staff. Recently, rapid tests for syphilis became available for use at the point of care. There are considerable advantages to this approach: the tests can be undertaken using a finger prick to obtain a small amount of blood, and require minimal staff training and no specialist laboratory equipment. A result can be given within minutes, avoiding the need for a return visit in settings where antenatal care is infrequent.
Why Was This Study Done?
Although the advantages to the mother and baby of testing seem clear, the cost-effectiveness of a screening and treatment program using rapid point-of-care tests has not previously been assessed for most sub-Saharan African countries. The program has the greatest potential value in settings where syphilis is common. In local guidelines, testing is often recommended, but uncertainty over the costs and technical requirements has meant that antenatal syphilis screening has not been comprehensively introduced. The aim of this study was to assess whether antenatal syphilis screening was cost-effective for 43 countries in sub-Saharan Africa by estimating the extent of infant mortality and disability that could be prevented if maternal syphilis was diagnosed and treated.
What Did the Researchers Do and Find?
The researchers created a model that allowed them to determine the cost-effectiveness of antenatal syphilis screening and treatment. They included many factors including the performance of the test, how common syphilis is in each country, the number of births, the likelihood of harmful outcomes, the effectiveness of penicillin therapy, the cost of an antenatal visit, and the cost of the test and the penicillin treatment, if positive. Then they calculated how many deaths and how much disability could be prevented by screening and treatment. The results were expressed in disability-adjusted life years (DALYs), which give the number of years affected by ill health, disability, or early death. The study found that screening was highly cost-effective, with each DALY prevented on average costing only US$11.
What Do These Findings Mean?
Across sub-Saharan Africa, only about 40% of women are screened for syphilis during one of their antenatal care visits. These findings suggest that it would be an efficient use of health care resources to scale up antenatal screening programs for syphilis using the rapid point-of-care test. Comparing these results to those for other health care interventions in resource-limited settings suggests that screening pregnant women for syphilis in sub-Saharan Africa could achieve a substantial improvement in public health at relatively little cost. The researchers propose that combining HIV and syphilis tests into one antenatal screening package could be an efficient way of introducing a care package into settings where uptake is currently limited.
Please access these websites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001545.
The World Health Organization provides information on syphilis in pregnant women
The London School of Hygiene & Tropical Medicine has information on efforts to reduce congenital syphilis and a rapid syphilis test toolkit
The US Centers for Disease Control and Prevention's STD Curriculum includes materials on syphilis