Immunization of expecting mothers to protect their children against Streptococcus group B infection
|
Reviewed & translated by Nhi Phuong Quynh Le, B.A.
Edited by Dat Tien Nguyen, B.A, ScM. |
Posted on August 23rd, 2023
|
Many history studies showed that serotype-specific anti–capsular polysaccharide (CPS) IgG in newborns correlated with a reduced risk of group B streptococcal disease. A hexavalent CPS–cross-reactive material 197 glycoconjugate vaccine (GBS6) is being developed as a maternal vaccine to prevent invasive group B streptococcus in young infants. Thus, a study was conducted to evaluate the effectiveness of maternal GBS6 vaccine to prevent group B Streptococcus for infants.
The phase 2 clinical randomized, placebo-controlled trial was conducted in South Africa including 494 healthy pregnant women from 18 to 40 years of age. The study participants were randomly assigned to receive a single dose of 5 μg, 10 μg, or 20 μg per serotype of GBS6 with or without aluminum phosphate (AlPO4) or placebo. The researchers collected serum samples from the participants before and after maternal immunization; cord blood or infant serum samples were obtained at delivery in order to assess for anti-CPS IgG. The researchers concluded that anti-CPS IgG concentrations were associated with a reduced risk of disease among infants; IgG thresholds that were determined to be associated with 75 to 95% reductions in the risk of disease were 0.184 to 0.827 μg per milliliter. In terms of safety, the researchers found that the incidence of adverse events was similar across the trial groups for both mothers and infants; more local reactions were observed in the groups that received GBS6 containing aluminum phosphate. Among the infants, minor congenital anomalies (umbilical hernia and congenital dermal melanocytosis) were reported as the most common serious adverse events.
The phase 2 clinical randomized, placebo-controlled trial was conducted in South Africa including 494 healthy pregnant women from 18 to 40 years of age. The study participants were randomly assigned to receive a single dose of 5 μg, 10 μg, or 20 μg per serotype of GBS6 with or without aluminum phosphate (AlPO4) or placebo. The researchers collected serum samples from the participants before and after maternal immunization; cord blood or infant serum samples were obtained at delivery in order to assess for anti-CPS IgG. The researchers concluded that anti-CPS IgG concentrations were associated with a reduced risk of disease among infants; IgG thresholds that were determined to be associated with 75 to 95% reductions in the risk of disease were 0.184 to 0.827 μg per milliliter. In terms of safety, the researchers found that the incidence of adverse events was similar across the trial groups for both mothers and infants; more local reactions were observed in the groups that received GBS6 containing aluminum phosphate. Among the infants, minor congenital anomalies (umbilical hernia and congenital dermal melanocytosis) were reported as the most common serious adverse events.