Group B Streptococcus Vaccine Research Articles

Maternal immunization.

Abstract Pregnant individuals and infants are at risk from vaccine-preventable diseases like severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza. Maternal vaccination during pregnancy can protect both the mother and child. Recent progress in developing these vaccines is notable, but vaccine hesitancy and the exclusion of pregnant individuals from clinical trials limit their use. Maternal immunization safeguards mothers from severe illness and adverse pregnancy outcomes while providing infants with antibodies through the placenta and breast milk. Inactivated vaccines are generally effective and safe during pregnancy. Limited safety and efficacy data due to exclusion from trials hinder vaccine uptake; however, vaccines like tetanus-diphtheria-acellular pertussis (Tdap), influenza, and SARS-CoV-2 have proven effective, and are recommended vaccines during pregnancy. New vaccines for group B Streptococcus (GBS) and cytomegalovirus are in development, with the GBS vaccine being the most advanced. Combating vaccine hesitancy through strong health care provider recommendations is vital to enhance uptake and protect pregnant individuals and their infants.

Synthesis and immunological study of tetrasaccharide repeating units of capsular polysaccharide of Group B Streptococcus serotype VIII and their protein conjugates

This study reports the efficient synthesis of three tetrasaccharide derivatives of Group B Streptococcus (GBS) serotype VIII capsular polysaccharide with alternative glycan sequences and spacer chains through a convergent chemical glycosylation manner or a one-pot three-enzyme assembly protocol. Using bifunctional glutarate ester as the linker, these synthesized oligosaccharides were efficiently conjugated with recombinant ScpA193 protein, generating the resultant oligosaccharide-ScpA193 conjugates with desirable carbohydrate loading. ELISA analysis of the antisera obtained from mice inoculated with the synthetic glycoconjugates showed the elicitation of strong oligosaccharide-specific immunoglobulin G (IgG) antibodies, suggesting the potential of the synthesized oligosaccharides for use in the development of GBS vaccines.

Surface protein distribution in Group B Streptococcus isolates from South Africa and identifying vaccine targets through in silico analysis.

Group B Streptococcus (GBS) is a major cause of pneumonia, sepsis, and meningitis in infants younger than 3 months of age. Furthermore, GBS infection in pregnant women is associated with stillbirths and pre-term delivery. It also causes disease in immunocompromised adults and the elderly, but the highest incidence of the disease occurs in neonates and young infants. At this time, there are no licensed vaccines against GBS. Complete GBS genome sequencing has helped identify genetically conserved and immunogenic proteins, which could serve as vaccine immunogens. In this study, in silico reverse vaccinology method were used to evaluate the prevalence and conservation of GBS proteins in invasive and colonizing isolates from South African infants and women, respectively. Furthermore, this study aimed to predict potential GBS vaccine targets by evaluating metrics such as antigenicity, physico-chemical properties, subcellular localization, secondary and tertiary structures, and epitope prediction and conservation. A total of 648 invasive and 603 colonizing GBS isolate sequences were screened against a panel of 89 candidate GBS proteins. Ten of the 89 proteins were highly genetically conserved in invasive and colonizing GBS isolates, nine of which were computationally inferred proteins (gbs2106, SAN_1577, SAN_0356, SAN_1808, SAN_1685, SAN_0413, SAN_0990, SAN_1040, SAN_0226) and one was the surface Immunogenic Protein (SIP). Additionally, the nine proteins were predicted to be more antigenic than the SIP protein (antigenicity score of > 0.6498), highlighting their potential as GBS vaccine antigen targets.

Maternal Streptococcus agalactiae colonization in Europe: data from the multi-center DEVANI study.

Despite national guidelines and use of intrapartum antibiotic prophylaxis (IAP), Streptococcus agalactiae (group B streptococci (GBS)) is still a leading cause of morbidity and mortality in newborns in Europe and the United States. The European DEVANI (Design of a Vaccine Against Neonatal Infections) program assessed the neonatal GBS infection burden in Europe, the clinical characteristics of colonized women and microbiological data of GBS strains in colonized women and their infants with early-onset disease (EOD). Overall, 1083 pregnant women with a GBS-positive culture result from eight European countries were included in the study. Clinical obstetrical information was collected by a standardized questionnaire. GBS strains were characterized by serological and molecular methods. Among GBS carriers included in this study after testing positive for GBS by vaginal or recto-vaginal sampling, 13.4% had at least one additional obstetrical risk factor for EOD. The five most common capsular types (i.e., Ia, Ib, II, III and V) comprised ~ 93% of GBS carried. Of the colonized women, 77.8% received any IAP, and in 49.5% the IAP was considered appropriate. In our cohort, nine neonates presented with GBS early-onset disease (EOD) with significant regional heterogeneity. Screening methods and IAP rates need to be harmonized across Europe in order to reduce the rates of EOD. The epidemiological data from eight different European countries provides important information for the development of a successful GBS vaccine.

Epidemiological observations of invasive group B Streptococcus infections in six major hospitals in Peninsular Malaysia

Objective: To address the lack of research on invasive group B Streptococcus (GBS) infections in Malaysia and Southeast Asia through a comprehensive analysis of GBS isolates obtained from hospitals. Methods: Medical records from patients with GBS infection isolated from the sterile site, such as blood and cerebrospinal fluid from 14 July 2019 to 15 December 2020, were reviewed from six major hospitals in Peninsular Malaysia. Inclusion criteria were invasive GBS, sterile sites and non-repeated GBS isolated from the same patients in the same admission. Viable isolates were re-identified for GBS and serotyped. Results: A total of 118 patients were eligible, with a majority of non-pregnant adults (76.3%). Over half of the patients (62.7%) had underlying medical conditions, with diabetes as the most common disease, followed by respiratory disease, renal disease, cardiovascular disease and skin and soft tissue disease. The most common manifestations were sepsis, followed by soft tissue abscess, diabetic foot ulcer, wet gangrene and cellulitis. The overall mortality was 7.6%. The most common serotype was serotype V. Conclusions: Invasive GBS infection among non-pregnant adults showed a rising trend, particularly among diabetic individuals. The study underscores the importance of reducing risk factors and highlights the necessity of developing GBS vaccination as a preventive strategy for both infants and adults.

Prevalence of group B Streptococcus colonisation in mother–newborn dyads in low-income and middle-income south Asian and African countries: a prospective, observational study

Rectovaginal group B Streptococcus (GBS) colonisation in pregnant individuals at the time of labour is a major risk factor for invasive GBS disease by age 7days (early-onset disease). We aimed to investigate the prevalence of rectovaginal GBS colonisation at the time of labour among pregnant women and vertical transmission to their newborns across selected low-income and middle-income African and south Asian countries. This prospective, observational study was undertaken at 11maternity and obstetric care facilities based in Ethiopia, Kenya, Mozambique, Nigeria, Mali, South Africa, Bangladesh, India, and Bhutan. HIV-negative pregnant women aged 18-45years who were in the early stages of labour and at least 37weeks' gestation were eligible for inclusion. Lower vaginal and rectal swabs and urine were collected from the women, and swabs of the umbilicus, outer ear, axillary fold, rectum, and throat were obtained from their newborns, for GBS culture. Standardised sampling and culture using direct plating and selective media broth for detection of GBS colonisation was undertaken at the sites. Serotyping of GBS isolates was done in South Africa. The primary outcome was the prevalence of rectovaginal GBS among pregnant women, analysed in participants with available data. This study is registered with the South African National Clinical Trials Register, number DOH-27-0418-4989. 6922pregnant women were enrolled from Jan 10, 2016, to Dec 11, 2018, of whom 6514 (94·1%; 759-892per country) were included in the analysis; data from Bhutan were not included in the study due to issues with specimen collection and processing. Overall, the prevalence of maternal GBS colonisation was 24·1% (95% CI 23·1-25·2; 1572of 6514); it was highest in Mali (41·1% [37·7-44·6]; 314of 764) and lowest in Ethiopia (11·6% [9·5-14·1]; 88of 759). Theoverall rate of vertical transmission of GBS from women with rectovaginal GBS colonisation was 72·3% (70·0-74·4; 1132of 1566); it was highest in Mozambique (79·2% [73·3-84·2]; 168of 212) and lowest in Bangladesh (55·8%, 47·5-63·8; 77of 138). The five most common GBS colonising serotypes were Ia (37·3% [34·9-39·7]; 586of 1572), V(28·5% [26·3-30·8]; 448of 1572), III (25·1% [23·0-27·3]; 394of 1572), II (9·2% [7·8-10·7]; 144of 1572), and Ib(6·5% [5·4-7·8]; 102of 1572). There was geographical variability in serotype proportion distribution; serotype VIIwas the third most common serotype in India (8·6% [5·3-13·7]; 15of 174) and serotype VI was mainly identified in Bangladesh (5·8% [3·0-11·0]; eight of 138) and India (5·7% [3·2-10·3]; ten of 174). Our study reported a high prevalence of GBS colonisation in most settings, with some geographical variability even within African countries. Our findings suggest that serotypes not included in current multivalent capsular-polysaccharide GBS vaccines prevail in some regions, so vaccine efficacy and post-licensure effectiveness studies should assess the effect of vaccination on maternal GBS colonisation given the potential for replacement by non-vaccine serotypes. Bill & Melinda Gates Foundation.

Group B streptococci in newborns in the first three months of life

Group B Streptococcus (GBS) disease in neonates occurs in two forms: early-onset disease (EOD), (day 0-6), and late-onset disease (LOD), (day 7-90). This review investigates that risk-based intrapartum screening and antibiotics have reduced the incidence of EOD, but not LOD, in Denmark. No clinical or laboratory tests can rule out GBS disease at symptom onset. Thus, a high proportion of uninfected infants receive antibiotics, although this varies widely, and may be reduced by strategies of antibiotic stewardship. A future GBS vaccine for pregnant women may potentially reduce disease burden and antibiotic exposure.

GBS vaccines in the UK: a round table discussion.

Group B streptococcus (GBS) remains a leading cause of infant sepsis, meningitis and death despite intrapartum antibiotic prophylaxis. A vaccine is urgently required, and two candidates are in advanced clinical trials. For successful GBS vaccine implementation, especially if a vaccine is licensed based on an immunological threshold, there must be cross-sector engagement, effective advocacy, robust plans for phase IV studies and equitable access. A round-table discussion, held at St George's University of London, reviewed the current position of GBS vaccines in the UK context, focusing on phase IV plans, convening a diverse group of stakeholders from across the UK, with a role in GBS vaccine licensure, advocacy, implementation or effectiveness evaluation.Presentations outlined the latest UK epidemiology, noting the rising infant invasive GBS (iGBS) infection rates from 1996 to 2021 for both early and late onset disease, with the highest disease rates in Black infants (1.1/1000 livebirths vs white infants (0.81/1000 livebirths). Potential coverage of the candidate vaccines was high (>95%). Regulatory input suggested that EU regulators would consider waiving the need for a pre-licensure efficacy study if a putative correlate of protection could be adequately justified. Phase IV study methodologies for a GBS vaccine were considered, largely based on previous UK maternal vaccine assessments, such as a nationwide cohort study design using a vaccine register and a maternal services dataset. Other strategies were also discussed such as a cluster or stepped-wedge randomised trial to evaluate implementation outcomes. Opportunities for advocacy, education and engagement with additional key partners were discussed and identified. With an approved GBS vaccine a near possibility, planning of phase IV studies and identification of critical barriers to implementation are urgently needed. Cross-sector engagement is essential and will facilitate a successful pathway.

Distributions of candidate vaccine Targets, virulence Factors, and resistance features of invasive group B Streptococcus using Whole-Genome Sequencing: A Multicenter, population-based surveillance study

BackgroundGroup B Streptococcus (GBS) is a leading cause of morbidity and mortality in young infants worldwide. This study aimed to investigate candidate GBS vaccine targets, virulence factors, and antimicrobial resistance determinants. MethodsWe used whole-genome sequencing to characterize invasive GBS isolates from infants < 3 months of age obtained from a multicenter population-based study conducted from 2015 to 2021 in China. ResultsOverall, seven serotypes were detected from 278 GBS isolates, four (Ia, Ib, III, V) of which accounted for 97.8 %. We detected 30 sequence types (including 10 novel types) that were grouped into six clonal complexes (CCs: CC1, CC10, CC17, CC19, CC23 and CC651); three novel ST groups in CC17 were detected, and the rate of CC17, considered a hyperinvasive neonatal clone complex, was attached to 40.6 % (113/278). A total of 98.9 % (275/278) of isolates harbored at least one alpha-like protein gene. All GBS isolates contained at least one of three pilus backbone determinants and the pilus types PI-2b and PI-1 + PI-2a accounted for 79.8 % of the isolates. The 112 serotype III/CC17 GBS isolates were all positive for hvgA. Most of the isolates (75.2 %) were positive for serine-rich repeat glycoprotein determinants (srr1or srr2). Almost all isolates possessed cfb (99.6 %), c1IE (100 %), lmb (95.3 %) or pavA (100 %) gene. Seventy-seven percent of isolates harboured more than three antimicrobial resistance genes with 28.4 % (79/278) gyrA quinoloneresistancedeterminants mutation, 83.8 % (233/278) carrying tet cluster genes and 77.3 % (215/278) carrying erm genes which mediated fluoroquinolone, tetracycline and clindamycin resistance, respectively.“ ConclusionsThe findings from this large whole-genome sequence of GBS isolates establish important baseline data required for further surveillance and evaluating the impact of future vaccine candidates.

Long-Term Co-Circulation of Host-Specialist and Host-Generalist Lineages of Group B Streptococcus in Brazilian Dairy Cattle with Heterogeneous Antimicrobial Resistance Profiles.

Group B Streptococcus (GBS) is a major cause of contagious bovine mastitis (CBM) in Brazil. The GBS population is composed of host-generalist and host-specialist lineages, which may differ in antimicrobial resistance (AMR) and zoonotic potential, and the surveillance of bovine GBS is crucial to developing effective CBM control and prevention measures. Here, we investigated bovine GBS isolates (n = 156) collected in Brazil between 1987 and 2021 using phenotypic testing and whole-genome sequencing to uncover the molecular epidemiology of bovine GBS. Clonal complex (CC) 61/67 was the predominant clade in the 20th century; however, it was replaced by CC91, with which it shares a most common recent ancestor, in the 21st century, despite the higher prevalence of AMR in CC61/67 than in CC91, and high selection pressure for AMR from indiscriminate antimicrobial use in the Brazilian dairy industry. CC103 also emerged as a dominant CC in the 21st century, and a considerable proportion of herds had two or more GBS strains, suggesting poor biosecurity and within-herd evolution due to the chronic nature of CBM problems. The majority of bovine GBS belonged to serotype Ia or III, which was strongly correlated with CCs. Ninety-three isolates were resistant to tetracycline (≥8 μg/mL; tetO = 57, tetM = 34 or both = 2) and forty-four were resistant to erythromycin (2.0 to >4 μg/mL; ermA = 1, ermB = 38, mechanism unidentified n = 5). Only three isolates were non-susceptible to penicillin (≥8.0 μg/mL), providing opportunities for improved antimicrobial stewardship through the use of narrow-spectrum antimicrobials for the treatment of dairy cattle. The common bovine GBS clades detected in this study have rarely been reported in humans, suggesting limited risk of interspecies transmission of GBS in Brazil. This study provides new data to support improvements to CBM and AMR control, bovine GBS vaccine design, and the management of public health risks posed by bovine GBS in Brazil.

Interlaboratory comparison of a multiplex immunoassay that measures human serum IgG antibodies against six-group B streptococcus polysaccharides

ABSTRACT Measurement of IgG antibodies against group B streptococcus (GBS) capsular polysaccharide (CPS) by use of a standardized and internationally accepted multiplex immunoassay is important for the evaluation of candidate maternal GBS vaccines in order to compare results across studies. A standardized assay is also required if serocorrelates of protection against invasive GBS disease are to be established in infant sera for the six predominant GBS serotypes since it would permit the comparison of results across the six serotypes. We undertook an interlaboratory study across five laboratories that used standardized assay reagents and protocols with a panel of 44 human sera to measure IgG antibodies against GBS CPS serotypes Ia, Ib, II, III, IV, and V. The within-laboratory intermediate precision, which included factors like the lot of coated beads, laboratory analyst, and day, was generally below 20% relative standard deviation (RSD) for all six serotypes, across all five laboratories. The cross-laboratory reproducibility was < 25% RSD for all six serotypes, which demonstrated the consistency of results across the different laboratories. Additionally, anti-CPS IgG concentrations for the 44-member human serum panel were established. The results of this study showed assay robustness and that the resultant anti-CPS IgG concentrations were reproducible across laboratories for the six GBS CPS serotypes when the standardized assay was used.

Maternal GBS vaccination for preventing group B streptococcus disease in newborns: A mini review of current evidence.

Group B streptococcus (GBS) poses a significant threat to neonates, leading to morbidity and mortality. Intrapartum antibiotics, although effective, have limitations, prompting the exploration of maternal vaccination. This study reviews the current evidence for maternal GBS vaccination in the prevention of early-onset GBS disease in newborns. A search on Google Scholar, PubMed, and Scopus identified studies assessing the impact of maternal GBS vaccination on early-onset GBS disease. Inclusion criteria comprised English-language clinical trials or observational studies. Data extraction included study details, immunogenicity profiles, effectiveness, safety outcomes, and relevant findings. Qualitative synthesis was employed for data analysis. Five studies meeting the inclusion criteria were reviewed. Maternal GBS vaccines demonstrated efficacy with sustained immunogenicity. Adverse events, although documented, were predominantly non-severe. Variability in immune responses and maternal-to-infant antibody ratios show the need for tailored vaccination approaches. Long-term follow up and surveillance are essential to assess persistence and identify unintended effects. Positive outcomes in vaccine efficacy support GBS vaccination integration into maternal health programs. Implementation challenges in diverse healthcare infrastructures require tailored approaches, especially in resource-limited settings. Overcoming cultural barriers and ensuring healthcare provider awareness are crucial for successful vaccination.

“Why has this new vaccine come and for what reasons?” key antecedents and questions for acceptance of a future maternal GBS vaccine: Perspectives of pregnant women, lactating women, and community members in Kenya

ABSTRACT Group B streptococcus (GBS) is a leading global cause of neonatal sepsis and meningitis, stillbirth, and puerperal sepsis. While intrapartum antibiotic prophylaxis (IAP) is a currently available GBS disease prevention strategy, IAP is programmatically complex to implement, precluding use in low- and middle-income countries. In Kenya, 2% of stillbirths are attributable to GBS infection. Two maternal GBS vaccines are in late-stage clinical development. However, licensure of a maternal GBS vaccine does not translate into reduction of disease. We conducted 28 in-depth interviews with pregnant people, lactating people, and community members across two counties in Kenya to better understand the attitudes and informational needs of primary vaccine beneficiaries. We identified two emerging themes from the data. The first focused on antecedents to maternal GBS vaccine acceptability. The most common antecedents focused on the vaccine’s ability to protect the baby and/or the mother, followed by community sensitization before the vaccine was available. The second key theme focused on questions that would need to be addressed before someone could accept a maternal GBS vaccine. Three key categories of questions were identified, including vaccine safety compared to vaccine benefits, who gets the vaccine, and how the vaccine works. Realizing the potential benefits of a future GBS maternal vaccine will require a multifactorial approach, including ensuring that communities are aware of GBS-related harms as well as the safety and effectiveness of a maternal GBS vaccine. Our study contributes to informing this multifactorial approach by elucidating the attitudes and concerns of key populations.

Serotype distribution, antimicrobial resistance, and molecular characterization of group B Streptococcus isolates from Chinese pregnant woman

Objective This study was aimed to investigate the serotypes, antibiotic susceptibilities, and multi-locus sequence type (MLST) profiles of group B Streptococcus (GBS) in the Beijing area. Methods Lower vaginal and rectal swabs were obtained from pregnant women of 35–37 gestational weeks (GWs) who attended the Beijing Obstetrics and Gynecology Hospital. All GBS isolates were identified with Gram staining, catalase reaction assays, and CAMP tests, followed by antibiotic susceptibility testing, serotype identification, multilocus sequence typing and erythromycin resistance gene analysis (ermB and mefE). Results From July 2020 to June 2022, 311 (5.17%) of 6012 pregnant women that were screened for GBS colonization were detected positive. Of the eight serotypes identified (III, Ia, Ib, IV, II, VIII, V, and NT), serotypes III (43.09%), Ia (34.08%) and Ib (17.04%) were the predominant species. In the antimicrobial susceptibility experiments, the resistant rates measured for erythromycin, clindamycin, levofloxacin, and tetracycline were 76.21%, 63.99%, 50.80%, and 81.03%, respectively, and 7.6% of GBS isolates showed inducible clindamycin in resistance (D-test phenotype). Meanwhile, the multilocus sequence typing analysis showed that sequence type 19 (ST19) (30.34%) and ST10 (18.62%) were the dominant sequence types. Among the 237 erythromycin-resistant isolates, 176 harbored ermB (128, 54.00%) or mefE (48, 20.30%) gene alone. Conclusion The infection rates, serotypes or MSLT distribution, and antimicrobial resistance of GBS in Beijing area were investigated, which may be applied in analyses of the epidemiological characteristics of GBS. This contributes to the basic knowledge required for successful GBS vaccine development suited for disease prevention and treatment in China, as well as the implementation of effective clinical antimicrobials.

207. The increased frequency and clinical characteristics of Streptococcus agalactiae serotype VIII from blood isolates at two tertiary care hospital in South Korea over 14 years

Abstract Background Invasive group B Streptococcus (GBS) infections are increasing among non-pregnant adults with underlying diseases. Previous studies have shown that the proportion of GBS serotype of pregnant women were differed from geographic regions. However, studies on the serotype of invasive GBS infection in non-pregnant adults are sparse. This study aimed to evaluate epidemiology and clinical characteristics of strains caused GBS bloodstream infection according to serotypes. Methods S. agalactiae blood isolates were collected between March 2007 and December 2021, and their clinical data were obtained from two tertiary hospital of South Korea. Species identification was performed using MALDI-TOF MS and serotyping test was performed using commercial latex particle agglutination kit. Antimicrobial susceptibility tests are conducted using automated equipment. Results A total of 130 patients with GBS bacteremia were identified and among them 125 isolates were serotypeable. The median age were 66 years and 46% were male. Serotype VIII was most dominant (31.5%) and Ib, III, Ia, V were as follows (20.8%, 13.8%, 12.3%, 11.5% retrospectively). The proportion of serotype VIII increased from 27.3% to 53.3% from 2015 to 2021. Most common source of GBS bloodstream infection were primary bacteremia (34.4%), followed by bone and joint infections (16.8%) and skin and soft tissue infections (13.6%). Cardiovascular disease (79.2%) was most frequently reported in GBS bacteremia patients, followed by malignancy (44.6%) and diabetes mellitus (40%). The 30-day mortality rate was 12.3% and there was no difference in 30-day mortality according to serotypes (log rank test P=0.39). In logistic regression analysis, high SOFA score was significantly associated with 30-day mortality (odd ratio 1.28, 95% C.I. 1.28-2.53, P&amp;lt; 0.01). All isolated GBS were susceptible to penicillin and resistances were identified against clindamycin, erythromycin and levofloxacin as 30%, 26.9%, 24.6% of the isolates, respectively. Conclusion We found the most common capsular serotype was VIII (31.5%) in Korea and the proportion of type VIII increasing over time. It is necessary to consider GBS vaccine in adults with underlying disease and its composition for serotype VIII according to epidemiologic characteristics. Disclosures All Authors: No reported disclosures

Preferences of pregnant women toward a future maternal Group B Streptococcus vaccine in China: A cross-sectional survey with a discrete choice experiment

ABSTRACT Group B streptococcus (GBS) is a major cause of neonatal death worldwide. A GBS vaccine for pregnant women is under development and is expected to be available in the near future. The perceptions and preferences of pregnant women in China of GBS vaccines has not been investigated, and this study aimed to investigate pregnant women‘s awareness of GBS and their potential preferences for the GBS vaccine. A discrete choice experiment was conducted among pregnant women in hospitals from Shaanxi, Hunan, and Zhejiang provinces located in Western, Central, and Eastern China, respectively. A conditional logit model was used to analyze the data and calculate willingness to pay values and choice probabilities of different GBS vaccine programs. A total of 354 pregnant women were included in the final analysis, 45.8% of whom were willing to receive a GBS vaccine if it were licensed. Vaccine safety was the most important attribute of a future vaccine, while cost was the least important attribute. Compared with no vaccination, pregnant women had a strong preference for future GBS vaccination (ASC = 1.267, p < .001). Pregnant women’s decisions were highly influenced by those of other pregnant women. Improving the safety, efficacy, and vaccination rate of the GBS vaccine in China is of great significance for future GBS vaccine development and vaccination. Compared to other variable options, the cost of a GBS vaccine was of the least importance among pregnant women in mainland China. These findings can inform public health policy decisions related to GBS vaccination in China.

EBNEO Commentary: Safety and immunogenicity of GBS vaccine in pregnancy and determination of a serocorrelate for infant protection.

EBNEO Commentary: Safety and immunogenicity of GBS vaccine in pregnancy and determination of a serocorrelate for infant protection.

Vaccine value profile for Group B streptococcus

Group B streptococcus (GBS) is a major global cause of neonatal meningitis, sepsis and pneumonia, with an estimated 91,000 infant deaths per year and an additional 46,000 stillbirths. GBS infection in pregnancy is also associated with adverse maternal outcomes and preterm births. As such, the World Health Organization (WHO) prioritised the development of a GBS vaccine suitable for use in pregnant women and use in LMICs, where the burden of disease is highest. Several GBS vaccines are in clinical development. The WHO Defeating Meningitis by 2030 has set a target of 2026 for vaccine licensure.This ‘Vaccine Value Profile’ (VVP) for GBS is intended to provide a high-level, holistic assessment of the information and data that are currently available to inform the potential public health, economic and societal value of pipeline vaccines and vaccine-like products. This VVP was developed by a working group of subject matter experts from academia, non-profit organizations, public private partnerships and multi-lateral organizations, and in collaboration with stakeholders from the WHO regions of AFR, AMR, EUR, WPR. All contributors have extensive expertise on various elements of the GBS VVP and collectively aimed to identify current research and knowledge gaps. The VVP was developed using only existing and publicly available information.

Near-term pregnant women in the Dominican Republic experience high rates of Group B Streptococcus rectovaginal colonization with virulent strains.

Maternal colonization with Group B Streptococcus (GBS) is an important cause of stillbirth, prematurity, and serious infection and death in infants worldwide. Resource constraints limit prevention strategies in many regions. Maternal GBS vaccines in development could be a more accessible prevention strategy, but data on geographic variations in GBS clones are needed to guide development of a broadly effective vaccine. In the Dominican Republic (DR), limited data suggest that pregnant women experience GBS colonization at rates among the highest globally. We aimed to determine the prevalence of maternal rectovaginal GBS colonization and describe clonal characteristics of colonizing strains in the DR. A cross-sectional study assessed rectovaginal GBS colonization in 350 near-term pregnant women presenting for routine prenatal care at an urban tertiary center in the DR. Rectovaginal samples were tested with chromogenic Strep B Carrot Broth and cultured for confirmatory whole-genome sequencing. In a secondary analysis, participants' demographics and histories were assessed for association with GBS colonization. Rectovaginal GBS colonization occurred in 26.6% of women. Serotypes Ia, Ib, II, III, IV, and V were detected, with no one serotype predominating; serotype III was identified most frequently (21.5%). Virulent and emerging strains were common, including CC17 (15.1%) and ST1010 (17.2%). In this first characterization of maternal GBS serotypes in the DR, we found high rates of rectovaginal colonization including with virulent and emerging GBS strains. The serotypes observed here are all targeted by candidate hexavalent GBS vaccines, suggesting effective protection in the DR.

Immunization with Multiple Virulence Factors Provides Maternal and Neonatal Protection against Group B Streptococcus Serotypes.

Group B streptococcus (GBS) commonly colonizes the vaginal tract and is a leading cause of life-threatening neonatal infections and adverse pregnancy outcomes. No effective vaccine is clinically available. Conserved bacterial virulence factors, including those of GBS, have been employed as vaccine components. We investigated serotype-independent protection against GBS by intranasal immunization with six conserved GBS virulence factors (GBSV6). GBSV6 induced systemic and vaginal antibodies and T cell responses in mice. The immunity reduced mouse mortality and vaginal colonization by various GBS serotypes and protected newborn mice of immunized dams against GBS challenge. Intranasal GBSV6 immunization also provided long-lasting protective immunity and had advantages over intramuscular GBSV6 immunization regarding restricting vaginal GBS colonization. Our findings indicate that intranasal immunization targeting multiple conserved GBS virulence factors induces serotype-independent immunity, which protects against GBS infection systemically and vaginally in dams and prevents newborn death. The study presents valuable strategies for GBS vaccine development.