The Association of Umbilical Cord Blood IgG Streptococcus pneumoniae and Hemophilus influenzae Antibody Titers with Mortality and Morbidity among HIV-exposed Infants in India

This study ended in August 2010.

In India, HIV-exposed infants (infants born to HIV-infected mothers), bear a large burden of mortality and morbidity from S. pneumoniae and H. influenzae type b infections. These bacterial respiratory pathogens are responsible for the majority of mortality and morbidity among infants worldwide in the first six months of life. In the setting of underlying HIV infection, the risk of S. pneumoniae and H. influenzae type b infections are greatly magnified. The 10-fold higher baseline childhood mortality in India compared to the United States, combined with the 7-fold higher HIV-specific mortality in HIV-infected children, results in substantial mortality, and further contributes to the burden of the S. pneumoniae and H. influenzae type b infections. In addition to these problems, maternal HIV infection also plays a large role in infant mortality and morbidity. These infants are exposed to the higher rates of respiratory infections in their HIV-infected mothers. Also, the main immunologic defense to these bacterial respiratory pathogens in HIV-exposed infants is dependent on maternally-derived IgG antibody to S. pneumoniae and H. influenzae type b, which is often insufficient because mothers themselves are not immunized to S. pneumoniae and H. influenzae type b. A significant percentage of S. pneumoniae and H. influenzae type b infections are vaccine preventable, but vaccines against these two bacteria are not included in the universal vaccination programs in India. Support for vaccination of HIV-infected mothers against these pathogens could be increased by clear documentation of the relationship between umbilical cord IgG antibody titers to S. pneumoniae and H. influenzae type b and infant mortality and morbidity. To address this hypothesis, we propose to measure IgG antibody titers to S. pneumoniae and H. influenza in umbilical cord blood and compare them to the incidences of mortality and morbidity in HIV-exposed infants in the first six months of life. We expect that HIV-exposed infants with low umbilical cord S. pneumoniae and H. influenzae type b IgG antibody titers will have higher mortality and morbidity than HIV-exposed infants with high titers. By boosting the umbilical cord IgG antibody titers to S. pneumoniae and H. influenzae type b with maternal vaccination against these respiratory pathogens, we may significantly improve health outcomes among HIV-exposed infants in India in the first six months of life. 

The aims of this study were: 

• To measure the S. pneumoniae IgG antibody titers to capsular serotypes 1, 5, 6b, and 19a in umbilical cord blood from HIV-exposed infants. 
• To measure the H. influenzae type b IgG antibody titer in umbilical cord blood from HIV-exposed infants. 
• To determine the association between umbilical cord S. pneumoniae and H. influenzae type b IgG antibody titers and the incidences of mortality and morbidity among HIV-exposed infants, in the first 6 months of life.