Neonatal protection and preterm birth reduction following maternal group B streptococcus vaccination in a mouse model.

PURPOSE: Evaluate effects of maternal immunization in a mouse model of Group B Streptococcus (GBS) vaginal colonization using clinical isolates. MATERIALS AND METHODS: Female pregnant mice were immunized with heat-killed GBS 21 days before pregnancy and were inoculated intravaginally with GBS cultures (5 × 107 CFU twice a day for three days) from the 16th day of pregnancy. Gestation period and mice survival were monitored. Maternal anti-GBS IgG levels have been determined by ELISA analysis in vaccinated, unvaccinated mothers and newborns. RESULTS: Maternal immunization before pregnancy provided protection to newborns for three of the four GBS strains used. Evaluation of the immunogenicity showed that this vaccination induced higher levels of IgG in vaccinated compared to unvaccinated dams and the presence of antibodies in the offspring at embryonic and postnatal age, and a Th1 response and high levels of IgG2a subclass antibody and IFN-γ were detected. A significant reduction of preterm births was observed in vaccinated mothers (p< 0.05). CONCLUSIONS: Our finding suggest that vaccinated mothers could protect their progeny from GBS infection and preterm birth through passive immunization. The proposed mouse model may represent a noninvasive and effective tool to investigate pathogenetic mechanisms of GBS ascending infection and for vaccine protection studies.

Immunization status of internationally adopted children in Rome, Italy.

AIMS: International adoption medicine is a relatively new specialty in pediatrics that has emerged to address the specific health care needs of internationally adopted children in high-income countries. This study ascertains the seroprotection rate for vaccine-preventable diseases, especially against pneumococcal diseases. PATIENTS AND METHODS: We evaluated 67 internationally adopted children that reached the International Adoption Unit of Bambino Gesù Children's Hospital, Rome-Italy. We collected demographic information, data from preadoption immunization records, results of laboratory testing for immunity to vaccine-preventable diseases (tetanus, pneumococcus, hepatitis B, hemophilus influenzae type b (Hib), measles), as well as results of screening for HIV, hepatitis C, quantiferon, immunological and nutritional status. RESULTS: For children that had received ≥3 vaccine doses of tetanus, overall protection was 94% of 31 vaccinated children; with 1-2 vaccine doses for hepatitis B and Hib respectively, protection was 45% of 29 vaccinated children and 63% of 8 vaccinated children, respectively. For children with one or more doses of measles vaccine, protection was 63% of 32 vaccinated children. Regarding pneumococcus vaccine (documented for eight children), 88% of children with one or more doses of vaccine had developed protective immunity. CONCLUSIONS: International adoptees without a valid vaccine record need to undergo a complete schedule in accordance with their age and should receive all the vaccines in the adoptive country's schedule.