Immunogenicity of tetanus, diphtheria and acellular pertussis vaccination among pregnant women living with and without HIV.

OBJECTIVE: Vaccination during pregnancy with tetanus-diphtheria-acellular pertussis (Tdap) vaccine is recommended to protect the young infants against pertussis. There is a paucity of data on immune responses to Tdap in pregnant women with HIV (PWWH), and its impact on the protection of their infants has not been described. METHODS: In an open label phase IV clinical trial in South Africa, we evaluated the immunogenicity and safety of Tdap in PWWH compared with HIV-uninfected women. Antigen-specific immunoglobulin G (IgG) to pertussis toxoid, filamentous haemagglutinin, pertactin, fimbriae, diphtheria and tetanus were measured by electrochemiluminescence-based multiplex assay. RESULTS: Overall, 91 PWWH and 136 HIV-uninfected pregnant women were enrolled. All PWWH were on antiretroviral treatment and 94.5% had HIV viral loads <40 copies per millilitre. Antibody levels prevaccination were lower among PWWH compared with HIV-uninfected women for all antigens. At 1 month postvaccination PWWH compared with HIV-uninfected women had lower fold-increase and antibody concentrations for all epitopes. Also, a lower proportion of PWWH achieved ≥4-fold increase from pre to postvaccination for pertussis toxoid and pertactin, or diphtheria IgG levels ≥0.1 IU/ml and ≥1 IU/ml postvaccination. Adverse events postvaccination were similar in PWWH and HIV-uninfected. CONCLUSION: Tdap vaccination was safe and immunogenic. PWHW had, however, attenuated humoral immune responses, which could affect the effectiveness of protecting their infants against pertussis compared with those born to women without HIV.ClinicalTrials.gov identifier: NCT05264662.

Potential for Maternally Administered Vaccine for Infant Group B Streptococcus.

BACKGROUND: Natural history studies have correlated serotype-specific anti-capsular polysaccharide (CPS) IgG in newborns 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. METHODS: In an ongoing phase 2, placebo-controlled trial involving pregnant women, we assessed the safety and immunogenicity of a single dose of various GBS6 formulations and analyzed maternally transferred anti-CPS antibodies. In a parallel seroepidemiologic study that was conducted in the same population, we assessed serotype-specific anti-CPS IgG concentrations that were associated with a reduced risk of invasive disease among newborns through 89 days of age to define putative protective thresholds. RESULTS: Naturally acquired anti-CPS IgG concentrations were associated with a reduced risk of disease among infants in the seroepidemiologic study. 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. No GBS6-associated safety signals were observed among the mothers or infants. The incidence of adverse events and of serious adverse events were 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, the most common serious adverse events were minor congenital anomalies (umbilical hernia and congenital dermal melanocytosis). GBS6 induced maternal antibody responses to all serotypes, with maternal-to-infant antibody ratios of approximately 0.4 to 1.3, depending on the dose. The percentage of infants with anti-CPS IgG concentrations above 0.184 µg per milliliter varied according to serotype and formulation, with 57 to 97% of the infants having a seroresponse to the most immunogenic formulation. CONCLUSIONS: GBS6 elicited anti-CPS antibodies against group B streptococcus in pregnant women that were transferred to infants at levels associated with a reduced risk of invasive group B streptococcal disease. (Funded by Pfizer and the Bill and Melinda Gates Foundation; C1091002 ClinicalTrials.gov number, NCT03765073.).

Evaluation of Clinical Case Definitions for Respiratory Syncytial Virus Lower Respiratory Tract Infection in Young Children.

BACKGROUND: Various case definitions of respiratory syncytial virus lower respiratory tract infection (RSV-LRTI) are currently proposed. We assessed the performance of 3 clinical case definitions against the World Health Organization definition recommended in 2015 (WHO 2015). METHODS: In this prospective cohort study conducted in 8 countries, 2401 children were followed up for 2 years from birth. Suspected LRTIs were detected via active and passive surveillance, followed by in-person clinical evaluation including single timepoint respiratory rate and oxygen saturation (by pulse oximetry) assessment, and nasopharyngeal sampling for RSV testing by polymerase chain reaction. Agreement between case definitions was evaluated using Cohen's κ statistics. RESULTS: Of 1652 suspected LRTIs, 227 met the WHO 2015 criteria for RSV-LRTI; 73 were classified as severe. All alternative definitions were highly concordant with the WHO 2015 definition for RSV-LRTI (κ: 0.95-1.00), but less concordant for severe RSV-LRTI (κ: 0.47-0.82). Tachypnea was present for 196/226 (86.7%) WHO 2015 RSV-LRTIs and 168/243 (69.1%) LRTI/bronchiolitis/pneumonia cases, clinically diagnosed by nonstudy physicians. Low oxygen saturation levels were observed in only 55/226 (24.3%) WHO 2015 RSV-LRTIs. CONCLUSIONS: Three case definitions for RSV-LRTI showed high concordance with the WHO 2015 definition, while agreement was lower for severe RSV-LRTI. In contrast to increased respiratory rate, low oxygen saturation was not a consistent finding in RSV-LRTIs and severe RSV-LRTIs. This study demonstrates that current definitions are highly concordant for RSV-LRTIs, but a standard definition is still needed for severe RSV-LRTI. CLINICAL TRIAL REGISTRATION: NCT01995175.

Single priming and booster dose of ten-valent and 13-valent pneumococcal conjugate vaccines and Streptococcus pneumoniae colonisation in children in South Africa: a single-centre, open-label, randomised trial.

BACKGROUND: Pneumococcal conjugate vaccine (PCV) immunisation has reduced vaccine-serotype colonisation and invasive pneumococcal disease in South Africa, providing the opportunity to consider transitioning from a two-dose (2 + 1) to one-dose (1 + 1) primary series and a booster dose. METHODS: In this single-centre, open-label, randomised trial done in South Africa, infants aged 35-49 days without HIV infection, without childhood immunisations except for BCG and polio, and with gestation age at delivery of at least 37 weeks of age, a birthweight of at least 2500 g, and weight of at least 3500 g at the time of enrolment were randomly assigned (1:1:1:1:1:1), through block randomisation (block size of 30), to receive a single priming dose of ten-valent PCV (PCV10) or 13-valent PCV (PCV13) at either 6 weeks (6-week 1 + 1 group) or 14 weeks (14-week 1 + 1 group), compared with two priming doses at 6 weeks and 14 weeks (2 + 1 group), followed by a booster dose at 9 months of age in all groups. The primary objective of the trial has been published previously. We report the secondary objective of the effect of alternative doses of PCV10 and PCV13 on serotype-specific Streptococcus pneumoniae colonisation at 9 months, 15 months, and 18 months of age and a further exploratory analysis in which we assessed non-inferiority of serotype-specific serum IgG geometric mean concentrations 1 month after the booster (10 months of age) and the percentage of participants with serotype-specific IgG titre above the putative thresholds associated with a risk reduction of serotype-specific colonisation between the 1 + 1 and 2 + 1 groups for both vaccines. Non-inferiority was established if the lower limit of the 95% CI for the difference between the proportion of participants (1 + 1 group vs 2 + 1 group) above the putative thresholds was greater than or equal to -10%. All analyses were done in the modified intention-to-treat population, which included all participants who received PCV10 or PCV13 according to assigned randomisation group and for whom laboratory results were available. The trial is registered with ClinicalTrials.gov, NCT02943902. FINDINGS: 1564 nasopharyngeal swabs were available for molecular serotyping from 600 infants who were enrolled (100 were randomly assigned to each of the six study groups) between Jan 9 and Sept 20, 2017. There was no significant difference in the prevalence of overall or non-vaccine serotype colonisation between all PCV13 or PCV10 groups. PCV13 serotype colonisation was lower at 15 months of age in the 14-week 1 + 1 group than in the 2 + 1 group (seven [8%] of 85 vs 17 [20%] of 87; odds ratio 0·61 [95% CI 0·38-0·97], p=0·037), but no difference was seen at 9 months (nine [11%] of 86 vs ten [11%] of 89; 0·92 [0·60-1·55], p=0·87) or 18 months (nine [11%] of 85 vs 11 [14%] of 87; 0·78 [0·45-1·22], p=0·61). Compared with the PCV13 2 + 1 group, both PCV13 1 + 1 groups did not meet the non-inferiority criteria for serotype-specific anti-capsular antibody concentrations above the putative thresholds purportedly associated with risk reduction for colonisation; however, the PCV10 14-week 1 + 1 group was non-inferior to the PCV10 2 + 1 group. INTERPRETATION: The serotype-specific colonisation data reported in this study together with the primary immunogenicity endpoints of the control trial support transitioning to a reduced 1 + 1 schedule in South Africa. Ongoing monitoring of colonisation should, however, be undertaken immediately before and after transitioning to a PCV 1 + 1 schedule to serve as an early indicator of whether PCV 1 + 1 could lead to an increase in vaccine-serotype disease. FUNDING: The Bill & Melinda Gates Foundation.

Safety and immunogenicity of VPM1002 versus BCG in South African newborn babies: a randomised, phase 2 non-inferiority double-blind controlled trial.

BACKGROUND: Tuberculosis is a major public health problem worldwide. Immunisation with Mycobacterium bovis BCG vaccine is partially effective in infants, reducing the incidence of miliary and tuberculosis meningitis, but is less effective against pulmonary tuberculosis. We aimed to compare safety and immunogenicity of VPM1002-a recombinant BCG vaccine developed to address this gap-with BCG in HIV exposed and HIV unexposed newborn babies. METHODS: This double-blind, randomised, active controlled phase 2 study was conducted at four health centres in South Africa. Eligible neonates were aged 12 days or younger with a birthweight of 2·5-4·2 kg, and could be HIV exposed (seropositive mothers) or unexposed (seronegative mothers). Newborn babies were excluded if they had acute or chronic illness, fever, hypothermia, sepsis, cancer, or congenital malformation, or if they received blood products or immunosuppressive therapy. Participants were excluded if their mothers (aged ≥18 years) had active tuberculosis disease, diabetes, a history of immunodeficiency except for HIV, hepatitis B or syphilis seropositivity, received blood products in the preceding 6 months, any acute infectious disease, or any suspected substance abuse. Participants were randomly assigned to VPM1002 or BCG vaccination in a 3:1 ratio, stratified by HIV status using the random number generator function in SAS, using a block size of eight paticipants. The primary outcome was non-inferiority (margin 15%) of VPM1002 to BCG vaccine in terms of incidence of grade 3-4 adverse drug reactions or ipsilateral or generalised lymphadenopathy of 10 mm or greater in diameter by 12 months. The primary outcome was assessed in all vaccinated participants (safety population) at regular follow-up visits until 12 months after vaccination. Secondary immunogenicity outcomes were interferon-γ levels and percentages of multifunctional CD4+ and CD8+ T cells among all lymphocytes across the 12 month study period. The study was registered with ClinicalTrials.gov, NCT02391415. FINDINGS: Between June 4, 2015 and Oct 16, 2017, 416 eligible newborn babies were randomly assigned and received study vaccine. Seven (2%) of 312 participants in the VPM1002 group had a grade 3-4 vaccine-related adverse reaction or lymphadenopathy of 10 mm or greater in diameter compared with 34 (33%) of 104 participants in the BCG group (risk difference -30·45% [95% CI -39·61% to -21·28%]; pnon-inferiority<0·0001); VPM1002 was thus non-inferior to BCG for the primary outcome. Incidence of severe injection site reactions was lower with VPM1002 than BCG: scarring occurred in 65 (21%) participants in the VPM1002 group versus 77 (74%) participants in the BCG group (p<0·0001); ulceration occurred in one (<1%) versus 15 (14%; p<0·0001); and abscess formation occurred in five (2%) versus 23 (22%; p<0·0001). Restimulated IFNγ concentrations were lower in the VPM1002 group than the BCG group at week 6, week 12, month 6, and month 12. The percentage of multifunctional CD4+ T cells was higher in the VPM1002 group than the BCG group at day 14 but lower at week 6, week 12, month 6, and month 12. The percentage of multifunctional CD8+ T cells was lower in the VPM1002 group than the BCG group at week 6, week 12, and month 6, but did not differ at other timepoints. INTERPRETATION: VPM1002 was less reactogenic than BCG and was not associated with any serious safety concern. Both vaccines were immunogenic, although responses were higher with the BCG vaccine. VPM1002 is currently being studied for efficacy and safety in a multicentric phase 3 clinical trial in babies in sub-Saharan Africa. FUNDING: Serum Institute of India.

Incidence of Respiratory Syncytial Virus Lower Respiratory Tract Infections During the First 2 Years of Life: A Prospective Study Across Diverse Global Settings.

BACKGROUND: The true burden of lower respiratory tract infections (LRTIs) due to respiratory syncytial virus (RSV) remains unclear. This study aimed to provide more robust, multinational data on RSV-LRTI incidence and burden in the first 2 years of life. METHODS: This prospective, observational cohort study was conducted in Argentina, Bangladesh, Canada, Finland, Honduras, South Africa, Thailand, and United States. Children were followed for 24 months from birth. Suspected LRTIs were detected via active (through regular contacts) and passive surveillance. RSV and other viruses were detected from nasopharyngeal swabs using PCR-based methods. RESULTS: Of 2401 children, 206 (8.6%) had 227 episodes of RSV-LRTI. Incidence rates (IRs) of first episode of RSV-LRTI were 7.35 (95% confidence interval [CI], 5.88-9.08), 5.50 (95% CI, 4.21-7.07), and 2.87 (95% CI, 2.18-3.70) cases/100 person-years in children aged 0-5, 6-11, and 12-23 months. IRs for RSV-LRTI, severe RSV-LRTI, and RSV hospitalization tended to be higher among 0-5 month olds and in lower-income settings. RSV was detected for 40% of LRTIs in 0-2 month olds and for approximately 20% of LRTIs in older children. Other viruses were codetected in 29.2% of RSV-positive nasopharyngeal swabs. CONCLUSIONS: A substantial burden of RSV-LRTI was observed across diverse settings, impacting the youngest infants the most. Clinical Trials Registration. NCT01995175.

Bacterial nasopharyngeal carriage following infant immunization with pneumococcal conjugate vaccines according to a 2+1 schedule in children in South Africa: an exploratory analysis of two clinical trials.

Background: We evaluated bacterial nasopharyngeal carriage (NPC) prevalence and cumulative acquisition following 7-valent pneumococcal conjugate vaccine (PCV7) or pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) administration. Methods: Participants were children from two clinical trials in a South African center who received PCV7 (n = 250) or PHiD-CV (n = 100) at ~6 weeks, ~14 weeks, and ~9-10 months of age, and were enrolled between Dec2009-Apr2010 and Mar2009-May2010 in the PCV7 and PHiD-CV studies, respectively. Sample collection, most microbiological assessments, and data re-analysis methods were identical. Results: NPC prevalence of any pneumococcal serotype was 18.5% and 17.0% at pre-vaccination, and 63.1% and 67.3% in 24-27 month-old children among PCV7 and PHiD-CV recipients, respectively. In 24-27 month-old children, 96.1% and 99.0% of PCV7 and PHiD-CV recipients had acquired ≥1 pneumococcal serotype, 53.7% and 62.9% ≥1 PCV7 serotype, 1.5%, and 3.1% ≥1 of serotypes 1, 5 or 7F, 23.2% and 19.6% serotype 6A, 23.2% and 21.7% serotype 19A, 88.7%, and 91.0% H. influenzae, and 50.3% and 62.9% Staphylococcus aureus, respectively. Conclusions: This analysis of two concurrent clinical trials did not reveal differences in bacterial NPC prevalence or acquisition in PCV7- and PHiD-CV-vaccinated children. Trial registration: South African National Clinical Trial Register (NHREC DOH-27-0511-299); ClinicalTrials.gov (NCT00829010).

Immunogenicity of a single-dose compared with a two-dose primary series followed by a booster dose of ten-valent or 13-valent pneumococcal conjugate vaccine in South African children: an open-label, randomised, non-inferiority trial.

BACKGROUND: Routine childhood immunisation with pneumococcal conjugate vaccine (PCV) has changed the epidemiology of pneumococcal disease across age groups, providing an opportunity to reconsider PCV dosing schedules. We aimed to evaluate the post-booster dose immunogenicity of ten-valent (PCV10) and 13-valent (PCV13) PCVs between infants randomly assigned to receive a single-dose compared with a two-dose primary series. METHODS: We did an open-label, non-inferiority, randomised study in HIV-unexposed infants at a single centre in Soweto, South Africa. Infants were randomly assigned to receive one priming dose of PCV10 or PCV13 at ages 6 weeks (6w + 1 PCV10 and 6w + 1 PCV13 groups) or 14 weeks (14w + 1 PCV10 and 14w + 1 PCV13 groups) or two priming doses of PCV10 or PCV13, one each at ages 6 weeks and 14 weeks (2 + 1 PCV10 and 2 + 1 PCV13 groups); all participants then received a booster dose of PCV10 or PCV13 at 40 weeks of age. The primary endpoint was geometric mean concentrations (GMCs) of serotype-specific IgG 1 month after the booster dose, which was assessed in all participants who received PCV10 or PCV13 as per the assigned randomisation group and for whom laboratory results were available at that timepoint. The 1 + 1 vaccine schedule was considered non-inferior to the 2 + 1 vaccine schedule if the lower bound of the 96% CI for the GMC ratio was greater than 0·5 for at least ten PCV13 serotypes and eight PCV10 serotypes. Safety was a secondary endpoint. This trial is registered with ClinicalTrials.gov (NCT02943902) and is ongoing. FINDINGS: Of 1695 children assessed, 600 were enrolled and randomly assigned to one of the six groups between Jan 9 and Sept 20, 2017; 542 were included in the final analysis of the primary endpoint (86-93 per group). For both PCV13 and PCV10, a 1+1 dosing schedule (either beginning at 6 or 14 weeks) was non-inferior to a 2 + 1 schedule. For PCV13, the lower limit of the 96% CI for the ratio of GMCs between the 1 + 1 and 2 + 1 groups was higher than 0·5 for ten serotypes in the 6w+1 group (excluding 6B, 14, and 23F) and 11 serotypes in the 14w + 1 group (excluding 6B and 23F). For PCV10, the lower limit of the 96% CI for the ratio of GMCs was higher than 0·5 for all ten serotypes in the 6w+1 and 14w + 1 groups. 84 serious adverse events were reported in 72 (12%) of 600 participants. 15 occurred within 28 days of vaccination, but none were considered to be related to PCV injection. There were no cases of culture-confirmed invasive pneumococcal disease. INTERPRETATION: The non-inferiority in post-booster immune responses following a single-dose compared with a two-dose primary series of PCV13 or PCV10 indicates the potential for reducing PCV dosing schedules from a 2 + 1 to 1 + 1 series in low-income and middle-income settings with well established PCV immunisation programmes. FUNDING: The Bill & Melinda Gates Foundation (OPP1 + 152352).

Short-term immunogenicity and safety of hepatitis-A and varicella vaccines in HIV-exposed uninfected and HIV-unexposed South African children.

BACKGROUND: HIV-exposed uninfected (HEU) children have increased risk of infectious morbidity during early childhood. We evaluated the short-term immunogenicity and safety of single dose inactivated hepatitis-A virus (HAV) vaccine and live attenuated varicella zoster virus (VZV) vaccine in South African children. METHODS: 195 HIV-unexposed and 64 HEU children received either one dose of HAV or VZV vaccine at 18 months of age. Blood samples were tested for hepatitis-A or VZV antibodies before and one month after vaccination by chemiluminescent microparticle immunoassay and enzyme-linked immunosorbent assay, respectively. All children were evaluated for solicited adverse events (AEs). RESULTS: One-month post-vaccination, a similar percentage of HIV-unexposed (91.8%) and HEU (82.9%) children were seropositive for hepatitis-A (p = 0.144). VZV antibody geometric mean fold-rise was also similar in HIV-unexposed (5.6; 95%CI: 4.6-6.7) and HEU children (5.1; 95%CI: 3.7-7.2); however, only 44% HIV-unexposed and HEU seroconverted (titers > 50 mIU/ml). AEs occurred with similar frequency and severity between groups, except for more systemic AEs after VZV vaccination in HEU than HIV-unexposed children. CONCLUSIONS: Single dose HAV and VZV vaccine was similarly immunogenic in HIV-unexposed and HEU children. We did not identify differences in short-term humoral immunity after administration of either a live attenuated or inactivated vaccine. Seroconversion rates after a single dose of VZV vaccine were, however, lower compared to reports from previous studies (85-89%). CLINICAL TRIALS REGISTRATION: NCT03330171.

Safety and immunogenicity of a parenteral trivalent P2-VP8 subunit rotavirus vaccine: a multisite, randomised, double-blind, placebo-controlled trial.

BACKGROUND: A monovalent, parenteral, subunit rotavirus vaccine was well tolerated and immunogenic in adults in the USA and in toddlers and infants in South Africa, but elicited poor responses against heterotypic rotavirus strains. We aimed to evaluate safety and immunogenicity of a trivalent vaccine formulation (P2-VP8-P[4],[6],[8]). METHODS: A double-blind, randomised, placebo-controlled, dose-escalation, phase 1/2 study was done at three South African research sites. Healthy adults (aged 18-45 years), toddlers (aged 2-3 years), and infants (aged 6-8 weeks, ≥37 weeks' gestation, and without previous receipt of rotavirus vaccination), all without HIV infection, were eligible for enrolment. In the dose-escalation phase, adults and toddlers were randomly assigned in blocks (block size of five) to receive 30 µg or 90 µg of vaccine, or placebo, and infants were randomly assigned in blocks (block size of four) to receive 15 µg, 30 µg, or 90 µg of vaccine, or placebo. In the expanded phase, infants were randomly assigned in a 1:1:1:1 ratio to receive 15 µg, 30 µg, or 90 µg of vaccine, or placebo, in block sizes of four. Participants, parents of participants, and clinical, data, and laboratory staff were masked to treatment assignment. Adults received an intramuscular injection of vaccine or placebo in the deltoid muscle on the day of randomisation (day 0), day 28, and day 56; toddlers received a single injection of vaccine or placebo in the anterolateral thigh on day 0. Infants in both phases received an injection of vaccine or placebo in the anterolateral thigh on days 0, 28, and 56, at approximately 6, 10, and 14 weeks of age. Primary safety endpoints were local and systemic reactions (grade 2 or worse) within 7 days and adverse events and serious adverse events within 28 days after each injection in all participants who received at least one injection. Primary immunogenicity endpoints were analysed in infants in either phase who received all planned injections, had blood samples analysed at the relevant timepoints, and presented no major protocol violations considered to have an effect on the immunogenicity results of the study, and included serum anti-P2-VP8 IgA, IgG, and neutralising antibody geometric mean titres and responses measured 4 weeks after the final injection in vaccine compared with placebo groups. This trial is registered with ClinicalTrials.gov, NCT02646891. FINDINGS: Between Feb 15, 2016, and Dec 22, 2017, 30 adults (12 each in the 30 µg and 90 µg groups and six in the placebo group), 30 toddlers (12 each in the 30 µg and 90 µg groups and six in the placebo group), and 557 infants (139 in the 15 µg group, 140 in the 30 µg group, 139 in the 90 µg group, and 139 in the placebo group) were randomly assigned, received at least one dose, and were assessed for safety. There were no significant differences in local or systemic adverse events, or unsolicited adverse events, between vaccine and placebo groups. There were no serious adverse events within 28 days of injection in adults, whereas one serious adverse event occurred in a toddler (febrile convulsion in the 30 µg group) and 23 serious adverse events (four in placebo, ten in 15 µg, four in 30 µg, and five in 90 µg groups) occurred among 20 infants, most commonly respiratory tract infections. One death occurred in an infant within 28 days of injection due to pneumococcal meningitis. In 528 infants (130 in placebo, 132 in 15 µg, 132 in 30 µg, and 134 in 90 µg groups), adjusted anti-P2-VP8 IgG seroresponses (≥4-fold increase from baseline) to P[4], P[6], and P[8] antigens were significantly higher in the 15 µg, 30 µg, and 90 µg groups (99-100%) than in the placebo group (10-29%; p<0·0001). Although significantly higher than in placebo recipients (9-10%), anti-P2-VP8 IgA seroresponses (≥4-fold increase from baseline) to each individual antigen were modest (20-34%) across the 15 µg, 30 µg, and 90 µg groups. Adjusted neutralising antibody seroresponses in infants (≥2·7-fold increase from baseline) to DS-1 (P[4]), 1076 (P[6]), and Wa (P[8]) were higher in vaccine recipients than in placebo recipients: p<0·0001 for all comparisons. INTERPRETATION: The trivalent P2-VP8 vaccine was well tolerated, with promising anti-P2-VP8 IgG and neutralising antibody responses across the three vaccine P types. Our findings support advancing the vaccine to efficacy testing. FUNDING: Bill & Melinda Gates Foundation.

Impact of HIV status and vaccination schedule on bacterial nasopharyngeal carriage following infant immunisation with the pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine in South Africa.

BACKGROUND: Nasopharyngeal carriage (NPC) of Streptococcus pneumoniae is a precondition for pneumococcal disease and a source of transmission. This trial evaluated NPC of S. pneumoniae and other pathogens post-vaccination with the pneumococcal non-typeable Haemophilus influenzae (NTHi) protein D conjugate vaccine (PHiD-CV) in human immunodeficiency virus (HIV)-infected (HIV+), HIV-exposed-uninfected (HEU), and HIV-unexposed-uninfected (HUU) South African children. METHODS: In this phase III, open, single-centre, controlled study (ClinicalTrials.gov: NCT00829010), 484 children were stratified by HIV status: 83 HIV+, 101 HEU, and 300 HUU. HIV+ and HEU children received a 3 + 1 PHiD-CV vaccination schedule: primary vaccination, age 6/10/14 weeks, and booster dose, age 9-10 months. HUU infants were randomised (1:1:1) to 3-dose priming and booster (HUU/3+1); 3-dose priming without booster (HUU/3+0); or 2-dose priming and booster (HUU/2+1). Bacterial NPC was assessed 8 times up to 24-27 months of age. RESULTS: Overall pneumococcal carriage rates were similar across 3+1 groups irrespective of HIV status; trends towards higher carriage rates in the HIV+ than HEU and HUU/3+1 groups were observed at 24-27 months of age. In HUU children, carriage of any pneumococcal serotype was similar for the three different dosing schedules at all timepoints; carriage of vaccine-type pneumococci tended to be lower at 16-19 months and 24-27 months of age in children who had received a booster dose (HUU/2+1 and HUU/3+1 groups) than in the HUU/3+0 group. Carriage rates of NTHi, Staphylococcus aureus and Moraxella catarrhalis were comparable between all groups. CONCLUSIONS: HIV infection or exposure did not seem to alter the effect of PHiD-CV on pneumococcal NPC in children during their first 2 years of life. NPC prevalence of vaccine-type pneumococci following vaccination series tended to be lower in children who had received a booster dose in comparison to those who had not.

Immunogenicity and Safety of an Early Measles Vaccination Schedule at 6 and 12 Months of Age in Human Immunodeficiency Virus (HIV)-Unexposed and HIV-Exposed, Uninfected South African Children.

BACKGROUND: Measles morbidity and mortality rates are greatest in children <12 months old, with increased susceptibility in human immunodeficiency virus (HIV)-exposed children. We evaluated the immunogenicity and safety of an early 2-dose measles vaccine regimen administered at 6 and 12 months of age in South Africa. METHODS: HIV-unexposed (HU) (n = 212) and HIV-exposed, uninfected (HEU) (n = 71) children received measles vaccination (CAM-70) at 6 and 12 months of age. Measles immunoglobulin G titers were measured by means of enzyme-linked immunosorbent assay before and 1 month after each vaccine dose. RESULTS: The majority of children (88.2% HU and 95.8% HEU; P = .04) were seronegative (<150 mIU/mL) to measles at 4.2 months of age. This was particularly evident among infants of mothers born from 1992 onwards (year of public nationwide measles vaccine availability). One month after the first measles vaccine, 42.3% of HU and 46.4% of HEU children were seropositive (≥330 mIU/mL). After the second dose, the proportion seropositive increased to 99.0% in HU and 95.3% in HEU children. Safety profiles were similar between HU and HEU children. CONCLUSIONS: Early 2-dose measles vaccination at 6 and 12 months of age was safe and induced antibody responses in HU and HEU children, which could partly offset the early loss of maternally derived antibodies in infants born to predominantly measles-vaccinated mothers. CLINICAL TRIALS REGISTRATION: NCT03330171.

Neutrophil Counts in Healthy South African Infants: Implications for Enrollment and Adverse Event Grading in Clinical Trials in an African Setting.

Absolute neutrophil counts are used to assess eligibility and safety during clinical trials but the toxicity grading scale used can affect enrollment and reporting of adverse events. During a trial investigating a parenteral rotavirus vaccine in South Africa, we excluded otherwise healthy infants without HIV infection from participation owing to neutropenia. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02109484.

Antibody Kinetics and Response to Routine Vaccinations in Infants Born to Women Who Received an Investigational Trivalent Group B Streptococcus Polysaccharide CRM197-Conjugate Vaccine During Pregnancy.

BACKGROUND: Maternal vaccination against group B Streptococcus (GBS) might provide protection against invasive GBS disease in infants. We investigated the kinetics of transplacentally transferred GBS serotype-specific capsular antibodies in the infants and their immune response to diphtheria toxoid and pneumococcal vaccination. METHODS: This phase 1b/2, observer-blind, single-center study (NCT01193920) enrolled infants born to women previously randomized (1:1:1:1) to receive either GBS vaccine at dosages of 0.5, 2.5, or 5.0 µg of each of 3 CRM197-glycoconjugates (serotypes Ia, Ib, and III), or placebo. Infants received routine immunization: combination diphtheria vaccine (diphtheria-tetanus-acellular pertussis-inactivated poliovirus/Haemophilus influenzae type b vaccine; age 6/10/ 14 weeks) and 13-valent pneumococcal CRM197-conjugate vaccine (PCV13; age 6/14 weeks and 9 months). Antibody levels were assessed at birth, day (D) 43, and D91 for GBS serotypes; 1 month postdose 3 (D127) for diphtheria; and 1 month postprimary (D127) and postbooster (D301) doses for pneumococcal serotypes. RESULTS: Of 317 infants enrolled, 295 completed the study. In infants of GBS vaccine recipients, GBS serotype-specific antibody geometric mean concentrations were significantly higher than in the placebo group at all timepoints and predictably decreased to 41%-61% and 26%-76% of birth levels by D43 and D91, respectively. Across all groups, ≥95% of infants were seroprotected against diphtheria at D127 and ≥91% of infants had seroprotective antibody levels against each PCV13 pneumococcal serotype at D301. CONCLUSIONS: Maternal vaccination with an investigational CRM197-glycoconjugate GBS vaccine elicited higher GBS serotype-specific antibody levels in infants until 90 days of age, compared with a placebo group, and did not affect infant immune responses to diphtheria toxoid and pneumococcal vaccination. CLINICAL TRIALS REGISTRATION: NCT01193920.

Safety and immunogenicity of a parenteral P2-VP8-P[8] subunit rotavirus vaccine in toddlers and infants in South Africa: a randomised, double-blind, placebo-controlled trial.

BACKGROUND: Efficacy of live oral rotavirus vaccines is reduced in low-income compared with high-income settings. Parenteral non-replicating rotavirus vaccines might offer benefits over oral vaccines. We assessed the safety and immunogenicity of the P2-VP8-P[8] subunit rotavirus vaccine at different doses in South African toddlers and infants. METHODS: This double-blind, randomised, placebo-controlled, dose-escalation trial was done at a single research unit based at a hospital in South Africa in healthy HIV-uninfected toddlers (aged 2 to <3 years) and term infants (aged 6 to <8 weeks, without previous rotavirus vaccination). Block randomisation (computer-generated, electronic allocation) was used to assign eligible toddlers (in a 6:1 ratio) and infants (in a 3:1 ratio) in each dose cohort (10 µg, followed by 30 µg, then 60 µg if doses tolerated) to parenteral P2-VP8-P[8] subunit rotavirus or placebo injection. The two highest tolerated doses were then assessed in an expanded cohort (in a 1:1:1 ratio). Parents of participants and clinical, data, and laboratory staff were masked to treatment assignment. P2-VP8-P[8] vaccine versus placebo was assessed first in toddlers (single injection) and then in infants (three injections 4 weeks apart). The primary safety endpoints were local and systemic reactions within 7 days after each injection, adverse events within 28 days after each injection, and all serious adverse events, assessed in toddlers and infants who received at least one dose. In infants receiving all study injections, primary immunogenicity endpoints were anti-P2-VP8-P[8] IgA and IgG and neutralising antibody seroresponses and geometric mean titres 4 weeks after the third injection. This trial is registered at ClinicalTrials.gov, number NCT02109484. FINDINGS: Between March 17, 2014, and Sept 29, 2014, 42 toddlers (36 to vaccine and six to placebo) and 48 infants (36 to vaccine and 12 to placebo) were enrolled in the dose-escalation phase, in which the 30 µg and 60 µg doses where found to be the highest tolerated doses. A further 114 infants were enrolled in the expanded cohort between Nov 3, 2014, and March 20, 2015, and all 162 infants (12 assigned to 10 µg, 50 to 30 µg, 50 to 60 µg, and 50 to placebo) were included in the safety analysis. Serum IgA seroresponses were observed in 38 (81%, 95% CI 67-91) of 47 infants in the 30 µg group and 32 (68%, 53-81) of 47 in the 60 µg group, compared with nine (20%, 10-35) of 45 in the placebo group; adjusted IgG seroresponses were seen in 46 (98%, 89-100) of 47 infants in the 30 µg group and 47 (100%; 92-100) of 47 in the 60 µg group, compared with four (9%, 2·5-21) of 45 in the placebo group; and adjusted neutralising antibody seroresponses against the homologous Wa-strain were seen in 40 (85%, 72-94) of 47 infants in both the 30 µg and 60 µg groups, compared with three (7%, 1·4-18) of 45 participants in the placebo group. Solicited reactions following any injection occurred with similar frequency and severity in participants receiving vaccine and those receiving placebo. Unsolicited adverse events were mostly mild and occurred at a similar frequency between groups. Eight serious adverse events (one with placebo, two with 30 µg, and five with 60 µg) occurred in seven infants within 28 days of any study injection, none of which were deemed related to study treatment. INTERPRETATION: The parenteral P2-VP8-P[8] vaccine was well tolerated and immunogenic in infants, providing a novel approach to vaccination against rotavirus disease. On the basis of these results, a phase 1/2 trial of a trivalent P2-VP8 (P[4], P[6], and P[8]) subunit vaccine is underway at three sites in South Africa. FUNDING: Bill & Melinda Gates Foundation.

Immunization with 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) according to different schedules in infants in South Africa: a phase III trial.

BACKGROUND: Limited clinical data exists to assess differences between various infant pneumococcal conjugate vaccine schedules. In this trial, we evaluated immunogenicity of the 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) administered using 3 different immunization schedules in HIV unexposed-uninfected infants in South Africa. METHODS: In this phase III, open, single-center, controlled study (clinicaltrials.gov: NCT00829010), 300 infants were randomized (1:1:1) to 1 of 3 PHiD-CV schedules: 3-dose priming and booster (3 + 1); 3-dose priming without booster (3 + 0); or 2-dose priming and booster (2 + 1). The booster was administered at 9-10 months of age. immune responses were assessed up to 21 months after primary vaccination. RESULTS: Post-priming antibody levels tended to be lower in the 2 + 1 group. At 6 months post-priming, antibody concentrations and opsonophagocytic activity titers were within similar ranges after 2- or 3-dose priming. Robust increases were observed pre- to post-booster in the 3 + 1 and 2 + 1 groups. CONCLUSIONS: PHiD-CV was immunogenic when administered in different schedules. Post-booster responses suggest effective immunological priming with both 2- and 3-dose primary series and support administration of the booster dose at 9-10 months of age.

Vaccination with 10-valent pneumococcal conjugate vaccine in infants according to HIV status.

BACKGROUND: Phase III, open-label, single-center, controlled study in South Africa (ClinicalTrials.gov: NCT00829010) to evaluate immunogenicity, reactogenicity, and safety of the 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) in human immunodeficiency virus (HIV)-infected (HIV+), HIV-exposed-uninfected (HEU), and HIV-unexposed-uninfected (HUU) children. METHODS: Children stratified by HIV status received PHiD-CV primary vaccination (age 6/10/14 weeks; coadministered with routine childhood vaccines) and booster dose (age 9-10 months). Immune responses, assessed using enzyme-linked immunosorbent and functional assays, and safety were evaluated up to 14 months post-booster. RESULTS: Of 83, 101, and 100 children enrolled in HIV+, HEU, and HUU groups, 70, 91, and 93 were included in according-to-protocol immunogenicity cohort. For each vaccine-serotype, percentages of children with antibody concentrations ≥0.2 µg/mL were ≥97% 1 month post-primary vaccination and ≥98.5% 1 month post-booster (except for 6B and 23F at both timepoints). Post-primary vaccination, functional antibody responses were lower in HIV+ children: for each vaccine-serotype, percentages of children with opsonophagocytic activity (OPA) titres ≥8 were ≥72%, ≥81%, and ≥79% for HIV+, HEU, and HUU children. Post-booster, ≥87% of children in each group had OPA titres ≥8. Reactogenicity was similar across groups. Thirty one (37%) HIV+, 25 (25%) HEU, and 20 (20%) HUU children reported ≥1 serious adverse event. Five HIV+ and 4 HEU children died. One death (sudden infant death syndrome; HEU group; 3 days post-dose 1) was considered potentially vaccine-related. CONCLUSION: PHiD-CV was immunogenic and well-tolerated in HIV+, HEU, and HUU children, and has the potential to provide substantial benefit irrespective of HIV infection status.

Safety and immunogenicity of an investigational maternal trivalent group B streptococcus vaccine in healthy women and their infants: a randomised phase 1b/2 trial.

BACKGROUND: Maternal group B streptococcus (GBS) serotype-specific capsular antibody concentrations are correlated with susceptibility to neonatal GBS invasive disease. Maternal immunisation against GBS during pregnancy might protect infants across the period of susceptibility to invasive disease, but no licensed vaccine exists. This study assessed the safety and immunogenicity of a CRM197-conjugated trivalent GBS vaccine in non-pregnant and pregnant women, and antibody transfer to their infants. METHODS: We did a phase 1b/2, randomised, observer-blind single-centre study of an investigational trivalent GBS vaccine in healthy non-pregnant women (cohort 1), and a dose-ranging study in healthy pregnant women (cohort 2). The study was done at the Chris Hani Baragwanath Academic Hospital in Soweto, South Africa. Participants were healthy non-pregnant or pregnant (28-35 weeks' gestation) women aged 18-40 years. In cohort 1, non-pregnant women were randomly assigned (2:1) to receive the investigational vaccine (two injections, 1 month apart, of a 20 µg dose [of each serotype] of aluminium hydroxide-adjuvanted investigational vaccine) or placebo. In cohort 2, pregnant women were randomly assigned (1:1:1:1) to receive one injection at 28-35 weeks' gestation of 0·5 µg, 2·5 µg, or 5·0 µg of the non-adjuvanted investigational vaccine (for each serotype), or placebo. All study participants and study staff not involved with vaccine preparation were masked to the randomisation group. The vaccine contained an equal dose (0·5 µg, 2·5 µg, 5·0 µg, or 20 µg) of each of three glycoconjugates (serotypes Ia, Ib and III). Reactogenicity was monitored to day 7 and unsolicited adverse events (adverse events) and infant safety were recorded throughout the study. The primary outcomes were tolerability and GBS-specific antibody response (measured as geometric mean concentrations [GMCs] in µg/mL) following the two injections for cohort 1, and selection of one vaccine dose based on analysis of serotype-specific antibody responses at delivery (+72 h) for use in subsequent studies. These outcomes were assessed in participants or infants of participants who correctly received the study vaccine with no major protocol deviations, and provided evaluable serum samples at day 1 and the scheduled timepoints throughout the study. This study is registered with ClinicalTrials.gov, NCT01193920. FINDINGS: Between Oct 5, 2010, and Sept 21, 2011, we screened 75 non-pregnant and 417 pregnant healthy South African women. Of these, 60 non-pregnant women were enrolled in cohort 1 (40 randomly assigned to the GBS 20 µg group and 40 randomly assigned to the placebo group) and 320 pregnant women were enrolled in cohort 2 (80 in each of the four groups). Among the randomised groups of pregnant women, 33-40% experienced at least one local and 54-71% one systemic solicited adverse event, less than 4% of which were severe, and the rate did not differ by study group. Also, 2% of the pregnancies resulted in stillbirth and 3·5% of the liveborn babies died by 12 months age, none of these deaths were attributed to vaccination. There was one death in a GBS-vaccine recipient, which too was unrelated to vaccination. For cohort 1, serotype-specific antibody concentrations were significantly higher, as evident by no overlap of the 95% CIs of GMCs against all three serotypes in the vaccinated group than the placebo group. For cohort 2, pregnant women in all vaccine groups had significantly higher GMCs than did those in the placebo group at delivery (eg, GMCs against serotype Ia were 11 µg/mL [95% CI 7·0-18] for the GBS vaccine 0·5 µg group, 18 µg/mL [11-29] for the GBS vaccine 2·5 µg group, 22 µg/mL [13-35] for the GBS vaccine 5·0 µg group, and 0·64 µg/mL [0·42-0·98] for the placebo group) and at all measured timepoints. GMCs did not differ significantly between the vaccine doses at any of the measured timepoints (p>0·05). INTERPRETATION: The vaccine was well tolerated and induced capsular-specific antibody responses, in non-pregnant and pregnant women. Maternal vaccination led to higher GBS serotype-specific antibody concentrations in infants than did placebo, with both interventions resulting in similar safety profiles. FUNDING: Novartis Vaccines and Diagnostics division, now part of the GlaxoSmithKline group of companies.

Group B streptococcus vaccination in pregnant women with or without HIV in Africa: a non-randomised phase 2, open-label, multicentre trial.

BACKGROUND: Neonates born to women infected with HIV are at increased risk for invasive group B streptococcus (GBS) disease. We aimed to compare safety and immunogenicity of trivalent glycoconjugate GBS vaccine in pregnant women with and without HIV in Malawi and South Africa. METHODS: In our non-randomised phase 2, open-label, multicentre study, we recruited pregnant women attending two antenatal clinics, one in Blantyre, Malawi, and one in Soweto, Johannesburg, South Africa. Participants were divided into three groups on the basis of their HIV infection status (no infection, infection and high CD4 cell count [>350 cells per µL], and infection and low CD4 cell count [>50 to ≤350 cells per µL]) and received a 5 µg dose of glycoconjugate GBS vaccine (serotypes Ia, Ib, and III, with CRM197 [Novartis Vaccines, Siena, Italy]) intramuscularly at 24-35 weeks' gestation. GBS serotype-specific antibody concentrations were measured before vaccination (day 1), day 15, day 31, and at delivery, and in infants at birth and day 42 of life. The primary outcomes were safety in mothers and infants and the amount of placental transfer of GBS serotype-specific antibodies from mothers to their infants. All immunogenicity and safety analyses were done on the full analysis set, including participants who, or whose mother, correctly received the vaccine and who provided at least one valid assessable serum sample. This study is registered with ClinicalTrials.gov, number NCT01412801. FINDINGS: 270 women and 266 infants were enrolled between Sept 26, 2011, and Dec 4, 2012 (90 women and 87 infants without HIV, 89 and 88 with HIV and high CD4 cell counts, and 91 and 91 with HIV and low CD4 cell counts, respectively). Seven women were lost to follow-up, six withdrew consent, one died, and two relocated. Eight infants died or were stillborn and two were lost to follow-up. Across serotypes, fold change in antibody concentrations were higher for the HIV-uninfected group than the HIV-infected groups. Transfer ratios were similar across all three groups (0·49-0·72; transfer ratio 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 infants born to women infected with HIV (0·52-1·62 µg/mL) than for those born to women not infected with HIV (2·67-3·91 µg/mL). 151 (57%) of 265 women reported at least one solicited adverse reaction: 39 (45%) of 87 women with HIV and low CD4 cell counts, 52 (59%) of 88 women with HIV and high CD4 cell counts, and 60 (67%) of 90 women in the HIV-uninfected group. 49 (18%) of 269 women had 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 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 serious. INTERPRETATION: The vaccine was less immunogenic in women 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 protection against invasive GBS disease. A validated assay and correlate of protection is needed to understand the potential protective value of this vaccine. FUNDING: Novartis Vaccines and Diagnostics division (now part of the GlaxoSmithKline group of companies), Wellcome Trust UK, Medical Research Council: Respiratory and Meningeal Pathogens Research Unit.

Burden of invasive group B Streptococcus disease and early neurological sequelae in South African infants.

INTRODUCTION: Group B Streptococcus (GBS) is a leading cause of neonatal sepsis and meningitis. We aimed to evaluate the burden of invasive early-onset (0-6 days of life, EOD) and late-onset (7-89 days, LOD) GBS disease and subsequent neurological sequelae in infants from a setting with a high prevalence (29.5%) of HIV among pregnant women. METHODS: A case-control study was undertaken at three secondary-tertiary care public hospitals in Johannesburg. Invasive cases in infants <3 months age were identified by surveillance of laboratories from November 2012 to February 2014. Neurodevelopmental screening was done in surviving cases and controls at 3 and 6 months of age. RESULTS: We identified 122 cases of invasive GBS disease over a 12 month period. Although the incidence (per 1,000 live births) of EOD was similar between HIV-exposed and HIV-unexposed infants (1.13 vs. 1.46; p = 0.487), there was a 4.67-fold (95%CI: 2.24-9.74) greater risk for LOD in HIV-exposed infants (2.27 vs. 0.49; p<0.001). Overall, serotypes Ia, Ib and III constituted 75.8% and 92.5% of EOD and LOD, respectively. Risk factors for EOD included offensive draining liquor (adjusted Odds Ratio: 27.37; 95%CI: 1.94-386.50) and maternal GBS bacteriuria (aOR: 8.41; 95%CI: 1.44-49.15), which was also a risk-factor for LOD (aOR: 3.49; 95%CI: 1.17-10.40). The overall case fatality rate among cases was 18.0%. The adjusted odds for neurological sequelae at 6 months age was 13.18-fold (95%CI: 1.44-120.95) greater in cases (13.2%) than controls (0.4%). DISCUSSION: The high burden of invasive GBS disease in South Africa, which is also associated with high case fatality rates and significant neurological sequelae among survivors, is partly due to the heightened risk for LOD in infants born to HIV-infected women. An effective trivalent GBS conjugate vaccine targeted at pregnant women could prevent invasive GBS disease in this setting.