Hecolin® is licensed in China and Pakistan indicated to be used for prevention of hepatitis E in healthy adult. The primary goal of this clinical trial is to establish the safety and immunogenicity of Hecolin® during pregnancy. As secondary and exploratory objectives, infant immune response through passive immunization of infants achieved through transplacental transfer of maternal IgG antibodies from the pregnant mother who has received Hecolin® in the second or third trimester will be evaluated.~Hecolin® follows a 3-dose schedule (0-1-6 months). For Arm 1 and 2, pregnant participants will receive 2 doses of Hecolin® or placebo at a 4 weeks interval and the third dose will be administered postpartum, approximately 20 weeks after the second dose. The neonates from these Arms will be followed for 24 weeks after birth. For Arm 3, non-pregnant participants will receive Hecolin® at 0-1-6 months schedule.~After each dose of IP injection to pregnant/non-pregnant participants, immediate AE (30 minutes post injection), solicited AE (7 days post injection), unsolicited AE (28 days post injection) and AESI/SAE (during the whole study period) will be collected.~For the immunogenicity subset, the participants' blood will be drawn before and 4 weeks post each dose of IP injection. At delivery, maternal blood will be drawn. Breast milk samples will be taken at delivery, 6 weeks, and 24 weekss after delivery.~All infant AESI/SAE will be collected throughout the study period and developmental assessment will be performed at age of 6 weeks, and 24 weeks. Blood will be drawn from infant immunogenicity subset at the same time points, umbilical cord blood (neonate blood will be collected if cord blood is not available for collection) at delivery, venous blood at age of 6 weeks and 24 weeks.
This is a phase II randomized, observer-blinded, placebo-controlled study with 3 arms enrolling a total of 2,358 participants. The arms are composed of Arm 1, pregnant participants receiving Hecolin® (N=1,104) with immunogenicity subset (n=150), Arm 2, pregnant participants receiving placebo (N=1,104) with immunogenicity subset (n=150), and Arm 3, non-pregnant participants receiving Hecolin® (N=150) of which all participants in this arm will be included in the immunogenicity subset.