256 (96%) of 266 infants enrolled completed the study across the groups. and the amount of placental transfer of GBS serotype-specific antibodies from mothers to their babies. All immunogenicity and security analyses were carried out on the full analysis arranged, including participants who, or whose mother, correctly received the vaccine and who offered at least one valid assessable serum sample. This study is definitely authorized with ClinicalTrials.gov, quantity NCT01412801. Findings 270 ladies and 266 babies were enrolled between Sept 26, 2011, and Dec 4, 2012 (90 ladies and 87 babies without HIV, 89 and 88 with HIV and high CD4 cell counts, and 91 and 91 STA-21 with HIV and low CD4 cell counts, respectively). Seven ladies were lost to STA-21 follow-up, six withdrew consent, one died, and two relocated. Eight babies died or were stillborn and two were lost to follow-up. Across serotypes, collapse switch in antibody concentrations were higher for the HIV-uninfected group than the HIV-infected organizations. Transfer ratios were related across all three organizations (049C072; transfer percentage is infant geometric mean antibody concentration in blood collected within 72 h of birth divided by maternal geometric mean antibody concentration in blood collected at delivery); however, at birth, maternally derived serotype-specific antibody concentrations were lower for babies born to ladies infected with HIV (052C162 g/mL) than for those born to ladies not infected with HIV (267C391 g/mL). 151 (57%) of 265 ladies reported at least one solicited adverse reaction: 39 (45%) of 87 ladies with HIV and low CD4 cell counts, 52 (59%) of 88 ladies with HIV and high CD4 cell counts, and 60 (67%) of 90 women in the HIV-uninfected group. 49 (18%) of 269 ladies experienced at least one adverse event deemed possibly related to the vaccine (six [7%] in the HIV and low CD4 cell count group, 12 [13%] in the HIV and high CD4 cell STA-21 count group, and 21 [23%] in the HIV-uninfected group), as did three (1%) of 266 neonates (zero, two [1%], and one [1%]); none of these events was regarded as severe. Interpretation The vaccine was less immunogenic in ladies infected with HIV than it was in those not infected, irrespective of CD4 cell count, resulting in lower levels of serotype-specific maternal antibody transferred to infants, which could reduce vaccine safety against invasive GBS disease. A validated assay and correlate of safety is needed to understand STA-21 the potential protecting value of this vaccine. Funding Novartis Vaccines and Diagnostics division (now part of the GlaxoSmithKline group of companies), Wellcome Trust UK, Medical Study Council: Respiratory and Meningeal Pathogens Study Unit. Introduction Several African countries including Malawi, Liberia, and Ethiopia have met their Millennium Development Goals for child mortality reduction; however, neonatal deaths caused by infections, preterm birth, and birth asphyxia account for 44% of mortality for children more youthful than 5 years.1 Group B streptococcus (GBS) has been identified as a leading cause of neonatal sepsis and meningitis in several countries across sub-Saharan Africa,2 and is therefore a crucial target for general public health treatment. In Africa, the reported incidence of early-onset invasive GBS disease varies across studies from 0 to 21 per 1000 livebirths, whereas late-onset invasive GBS disease varies from 0 to 089 per 1000 livebirths, with case fatality rates ranging from 13% to 46%.2 Intrapartum antibiotic prophylaxis has substantially reduced, although not eliminated, early-onset invasive GBS disease in high-income countries.3 Intrapartum antibiotic prophylaxis is hard to implement in resource-poor settings and has little effect on the incidence of late-onset invasive GBS disease.4 Study in context Evidence before this study We searched PubMed and VHL Web of Technology for studies on group B streptococcus (GBS) vaccines published before Dec 1, 2015, using the search terms Group B Streptococcus vaccine and combinations thereof. We did not find any earlier GBS vaccines that had been tested on pregnant women infected with HIV, and no published study on CRM197-conjugated GBS vaccines in human beings. Added value of this study This is the 1st study investigating the security and immunogenicity of a candidate glycoconjugate GBS vaccine in pregnant women infected with.