Treatment of Pregnant Women with Ivermectin during Mass Drug Distribution: Time to Investigate Its Safety and Potential Benefits

Abstract

To date, pregnant women are excluded from programmes delivering community-directed treatment of ivermectin (CDTI) for onchocerciasis and preventive chemotherapy of other helminthiases because of concerns over ivermectin safety during pregnancy. This systematic exclusion sustains an infection reservoir at the community level and deprives a vulnerable population from known benefits—there are indications that treating O. volvulus infected women may improve pregnancy outcomes and reduce the risk that their children develop onchocerciasis-associated morbidities. Furthermore, teratogenic effects are seen in non-clinical experiments at doses that far exceed those used in CDTI. Lastly, early, undetected and undeclared pregnancies are being systematically exposed to ivermectin in practice. Treatment of this population requires appropriate supporting evidence, for which we propose a three-pronged approach. First, to develop a roadmap defining the key steps needed to obtain regulatory clearance for the safe and effective use of ivermectin in all pregnant women who need it. Second, to conduct a randomised placebo-controlled double-blind clinical trial to evaluate the safety and benefits of ivermectin treatment in O. volvulus infected pregnant women. Such a trial should evaluate the possible effects of ivermectin in reducing adverse pregnancy outcomes and neonatal mortality, as well as in reducing the incidence of onchocerciasis-associated epilepsy. Third, to establish a pregnancy registry for women who inadvertently received ivermectin during pregnancy. This situation is not unique to ivermectin. Access to valuable therapies is often limited, delayed, or denied to pregnant women due to a lack of evidence. Concerns over protecting vulnerable people may result in harming them. We need to find acceptable ways to build robust evidence towards providing essential interventions during pregnancy.

Nodding Syndrome, a Case-control Study in Mahenge, Tanzania: <em>Onchocerca volvulus </em>and not <em>Mansonella </em><em>perstans</em> as Risk Factor

“…In a case-control study in Northern Uganda, preterm birth was found to be a risk factor for NS [49]. As preterm birth could be related to an O. volvulus infection of the pregnant mother [50], it was suggested that an O. volvulus infection of the mothers could cause a "parasitic tolerance" in their offspring. This tolerance can induce a higher load of O. volvulus microfilarial infection when the children are exposed to O. volvulus-infected blackflies than if the mothers were free of infection during pregnancy [51].…”

Nodding syndrome, a case-control study in Mahenge, Tanzania: Onchocerca volvulus and not Mansonella perstans as a risk factor

“…In a case-control study in northern Uganda, preterm birth was found to be a risk factor for NS [64]. As preterm birth could be related to an O. volvulus infection of the pregnant mother [65], it was suggested that an O. volvulus infection of the mothers could cause a "parasitic tolerance" in their offspring. This tolerance could induce a higher load of O. volvulus microfilarial infection after the children are exposed to O. volvulus-infected blackflies than if the mothers were free of infection during pregnancy [66].…”