Pregnant women who have been diagnosed with syphilis can be cured with an injection of benzathine penicillin, a type of antibiotic which can kill the bacteria and which can also prevent mother-to-child transmission of this infection (congenital syphilis). Newly published evidence shows however, that shortages of benzathine penicillin have been reported by countries where there is high number of pregnant women and infants infected with syphilis.
Shortages of this antibiotic mean that pregnant women who have been diagnosed with syphilis may not receive the treatment they need to prevent adverse birth and health outcomes.
Estimates of need for benzathine penicillin for the treatment of pregnant women diagnosed with syphilis during antenatal care visits in 30 high-morbidity countries, have been published in the journal PLOS ONE. The estimates show that the total number of women requiring treatment in these countries with at least one injection of the antibiotic during pregnancy to prevent congenital syphilis to be 351,016.
The authors of the study also note that if current WHO guidance on benzathine pencillin dosage were to be followed , then 351,016 doses of the penicillin would be needed for the live-born infants of mothers who test positive for syphilis.
How the numbers were calculated
The estimates were calculated by taking into account proportions of antenatal care attendance, syphilis screening coverage in pregnancy, and syphilis prevalence among pregnant women, which were reported to WHO, and applied to 2012 birth estimates for these 30 high syphilis burden countries to estimate the amount of current and potential benzathine penicillin needed to prevent congenital syphilis.
Real need may be greater
The real global demand for this type of penicillin is unknown. According to a forthcoming editorial to be published in the WHO Bulletin, an estimated 4.6 million adults become infected with syphilis globally each year. People who are infected with syphilis sometimes do not have noticeable symptoms, and therefore often go undiagnosed – either because they do not seek care, or because they are unable to access health care and/or diagnostic tests. This issue is critical for pregnant women who may unknowingly pass on the infection if not tested, diagnosed, and treated early in pregnancy.
What is more, the number of infants with congenital syphilis – who require a different regimen of treatment from adults – is difficult to calculate; infants born to untested and undiagnosed women with syphilis, who do not have noticeable symptoms, may go undiagnosed.
Shortages of benzathine penicillin of several years were recognised by the World Health Assembly in May 2016. In addition, WHO has received reports of shortages by antenatal health care workers in countries and other UN partners across three WHO regions. As a result WHO is now collaborating with stakeholders to identify countries that are experiencing shortages and also to help monitor the global availability of benzathine penicillin, to better understand the difference between the global demand and the global need for the antibiotic.
Progress relies on availability
WHO guidance, as part of the global plan for the elimination of mother-to-child transmission of syphilis, recommends a target that 95% of pregnant women who receive antenatal care should be tested for syphilis, and 95% of those women diagnosed should be treated. These targets are only achievable, and a continuation of recent progress is only possible, if the availability of benzathine penicillin can be ensured.
Significant progress has been made to reduce mother-to-child transmission of syphilis – with elimination achieved first in Cuba in 2015, then more recently, Thailand, Belarus, and the Republic of Moldova in 2016. Recently published research shows that according to 2012 estimates, there has been an approximate 39% reduction in maternal syphilis since the last estimates were published in 2008. Major progress was made by India, who represented 65% of the decrease, and when India was excluded from the analysis, figures still showed a noteworthy worldwide reduction in maternal and congenital syphilis of 18%.