Immunogenicity,safety and reactogenicity of a Phase II trial of Vi-DT typhoid conjugate vaccine in healthy Filipino infants and toddlers: A preliminary report

BackgroundTyphoid fever remains an important public health problem in developing countries and is endemic in many parts of Asia and Africa where the incidence of disease typically peaks in school-aged children. Age restrictions and other limitations of existing oral live-attenuated typhoid and parenteral Vi polysaccharide vaccines have triggered the development of Vi conjugate vaccines with improved immunological properties, use in younger age range, and longer durability of protection. We present the safety, reactogenicity, and immunogenicity data from a Phase II study after a single dose of Vi polysaccharide conjugated to diphtheria toxoid (Vi-DT) conducted in 6–23-month old Filipino children.MethodsThis is a randomized, observer-blinded Phase II study to assess the immunogenicity, safety and reactogenicity of Vi-DT compared to placebo, conducted in Muntinlupa City, The Philippines. Participants aged 6–23 months were enrolled and randomized to Vi-DT (25 µg) or placebo (0.9% sodium chloride) and evaluated for immunogenicity and overall safety 28 days post vaccination.ResultsA total of 285 participants were enrolled and age-stratified: 6 to < 9 months, 9–12 months, and 13–23 months. Seventy-six (76) participants received Vi-DT and 19 received placebo per each strata. All participants seroconverted after a single dose of Vi-DT versus 7% of placebo recipients. Anti-Vi IgG GMT was 444.38 [95% CI (400.28; 493.34)] after a single dose of Vi-DT; there was no change in GMT after placebo administration, 0.41 [95% CI (0.33; 0.51), p < 0.0001]. A similar pattern of immunogenicity was reported across all age strata. The vaccine reported to be safe and well tolerated.ConclusionsVi-DT vaccine was immunogenic, safe, and well tolerated in children aged 6–23 months.ClinicalTrials.gov registration number: NCT03527355.     

Safety and immunogenicity of a Vi-DT typhoid conjugate vaccine: Phase I trial in Healthy Filipino adults and children

BackgroundTyphoid fever remains a major public health problem in low- and middle-income countries where children aged 2–14 years bear the greatest burden. Vi polysaccharide is poorly immunogenic in children <2 years of age, and protection in adults is modest. The limitations of Vi polysaccharide vaccines can be overcome by conjugation of the Vi to a carrier protein. A typhoid conjugate vaccine composed of Vi polysaccharide conjugated to diphtheria toxoid (Vi-DT) has been developed. The Phase I study results are presented here.MethodsThis was a randomized, observer-blinded Phase I study to assess the safety and immunogenicity of Vi-DT compared to Vi polysaccharide vaccine, conducted in Manila, Philippines. Participants enrolled in an age de-escalation manner (18–45, 6–17 and 2–5 years) were randomized between Test (Vi-DT, 25 µg) administered at 0 and 4 weeks and Comparator (Vi polysaccharide, Typhim Vi® and Vaxigrip®, Sanofi Pasteur) vaccines.ResultsA total of 144 participants were enrolled (48 by age strata, 24 in Test and Comparator groups each). No serious adverse event was reported in either group. Solicited and unsolicited adverse events were mild or moderate in both groups with the exception of a 4-year old girl in Test group with grade 3 fever which resolved without sequelae. All participants in Test group seroconverted after first and second doses of Vi-DT while the proportions in the Comparator group were 97.1% and 97.2%, after first dose of Typhim Vi® and second dose of Vaxigrip®, respectively. Vi-DT showed 4-fold higher Geometric Mean Titers (GMT) compared to Typhim Vi® (adjusted for age strata, p < 0.001). No further increase of GMT was detected after the second dose of Vi-DT. Anti-DT IgG seroresponse rates were 81.2% and 84.5% post first and second Vi-DT doses, respectively.ConclusionsVi-DT vaccine was safe, well-tolerated and immunogenic in participants aged 2–45 years.ClinicalTrials.gov registration number: NCT02645032.     

Immunogenicity of meningococcal polysaccharide conjugate vaccine as a replacement for meningococcal polysaccharide vaccine in children in Guangzhou,China

To assess the durability of antibody persistence after substitution of the MPCV vaccine for the MPSV-A vaccine in children, an observational study was conducted in children who voluntarily received two doses of MPCV-AC instead of MPSV-A between March 2017 and March 2018 in Guangzhou, China. In total, 131 and 47 participants were enrolled in the 3-year-old and 6-year-old groups, respectively. In the 3-year-old group, the seroprotection rate and GMT values for Men A and Men C were raised significantly after 1-month post- dose 1 MPSV booster vaccination. All immune indicators were significantly lower in pre- dose 1 MPSV booster vaccination in the 3-year-old group than after pre- dose 2 MPSV booster vaccination in the 6-year-old group. While no significant differences were found in most immune indicators between the 1-month post- dose 1 MPSV booster vaccination in the 3-year-old group and pre- dose 2 MPSV booster vaccination in 6-year-old group. The substitute meningococcal immunization schedule showed a good immunogenicity in young children, and good sequential immunogenicity with MPSV booster immunization.     

某新上市国产冻干A+C群脑膜炎球菌多糖结合疫苗免疫原性及安全性观察

目的评价某新上市国产冻干A+C群脑膜炎球菌多糖结合疫苗接种婴幼儿的安全性和免疫原性。方法采用随机、盲法、对照的方法,选择900名6~23月龄健康儿童,其中6~11月龄300人,12~23月龄600人,每个年龄组按1∶1比例随机分到试验组和对照组。实验组接种某新上市疫苗,对照组接种罗益(无锡)生物制药有限公司生产的同类疫苗。每人接种2剂疫苗,间隔1个月,评价试验组和对照组疫苗免疫后不良反应发生率、抗体阳转率及抗体几何平均滴度(GMT)。结果免疫后两个年龄段A、C群抗体阳转(4倍增长)率均95%,试验组与对照组的阳转率差异无统计学意义。12~23月龄接种1剂、2剂疫苗后抗体阳转率差异无统计学意义;6~11月龄段,试验组A群抗体水平高于对照组;两个年龄段试验组的C群抗体水平均低于对照组,但均处于较高水平(1∶128)。实验组与对照组全身及局部不良反应率差异无统计学意义,未观察到与试验疫苗相关的严重不良事件。结论某新上市国产冻干A+C群脑膜炎球菌多糖结合疫苗在6~23月龄的儿童中具有良好安全性和免疫原性。     

Development of a bivalent conjugate vaccine candidate against malaria transmission and typhoid fever

Immune responses to poorly immunogenic antigens, such as polysaccharides, can be enhanced by conjugation to carriers. Our previous studies indicate that conjugation to Vi polysaccharide of Salmonella Typhi may also enhance immunogenicity of some protein carriers. We therefore explored the possibility of generating a bivalent vaccine against Plasmodium falciparum malaria and typhoid fever, which are co-endemic in many parts of the world, by conjugating Vi polysaccharide, an approved antigen in typhoid vaccine, to Pfs25, a malaria transmission blocking vaccine antigen in clinical trials. Vi-Pfs25 conjugates induced strong immune responses against both Vi and Pfs25 in mice, whereas the unconjugated antigens are poorly immunogenic. Functional assays of immune sera revealed potent transmission blocking activity mediated by anti-Pfs25 antibody and serum bactericidal activity due to anti-Vi antibody. Pfs25 conjugation to Vi modified the IgG isotype distribution of antisera, inducing a Th2 polarized immune response against Vi antigen. This conjugate may be further developed as a bivalent vaccine to concurrently target malaria and typhoid fever.     

Phase 1 trial of a 20-valent pneumococcal conjugate vaccine in healthy adults

IntroductionStreptococcus pneumoniae is a leading cause of bacteremia, bacterial pneumonia, and meningitis, and is associated with substantial morbidity and mortality, particularly in those under 2 years of age and those over 65 years of age. While significant progress against S. pneumoniae-related disease has been made as a result of the introduction of pneumococcal conjugate vaccines (PCV7, PCV10 and PCV13), there remains value in further expanding pneumococcal vaccine serotype coverage. Here we present the first report of a 20-valent pneumococcal conjugate vaccine (PCV20) containing capsular polysaccharide conjugates present in PCV13 as well as 7 new serotypes (8, 10A, 11A, 12F, 15B, 22F, and 33F) which are important contributors to pneumococcal disease.MethodsThis Phase I first-in-human study was a randomized, controlled, observer-blinded study with a two-arm parallel design to assess the safety, tolerability, and immunogenicity of PCV20 in adults. A total of 66 healthy adults 18–49 years of age with no history of pneumococcal vaccination were enrolled and randomized to receive a single dose of PCV20 or a licensed tetanus, diphtheria, acellular pertussis combination vaccine (Tdap) control. Local injection site reactions, select systemic symptoms, laboratory studies, and adverse events were assessed. Opsonophagocytic activity (OPA) titers and IgG concentrations were measured in sera collected prior to, and approximately one month (28–35 days) after vaccination.ResultsVaccination with PCV20 elicited substantial IgG and functional bactericidal immune responses as demonstrated by increases in IgG geometric mean concentrations (GMCs) and OPA geometric mean titers (GMTs) to the 20 vaccine serotypes. The overall safety profile of PCV20 was similar to Tdap, and generally consistent with that observed after PCV13 administration.ConclusionsVaccination with PCV20 was well tolerated and induced substantial functional (OPA) and IgG responses to all vaccine serotypes. There were no safety issues identified in this Phase 1 study, and the data supported further evaluation of PCV20.     

大规模冻干A+C群脑膜炎球菌多糖结合疫苗接种后 安全性观察

摘要:目的　了解冻干A+C群脑膜炎球菌多糖结合疫苗（MCV-A/C）在大规模人群中使用的安全性。方法　对入选的9 111名3～71月龄的婴幼儿接种MCV-A/C,3～5月龄儿童免疫3针,每针间隔1个月;6～23月龄儿童免疫2针,每针间隔1个月;24～71月龄儿童免疫1针。对他们进行全身及局部不良反应观察和记录。结果　总的局部不良反应率为1.63%,各种局部不良症状发生率分别为发红0.86%、肿胀0.54%、硬结0.48%、疼痛0.33%、瘙痒0.54%,均低于1%;总的全身不良反应率为14.98%,除发热发生率为12.75%外,其余全身不良症状发生率分别为皮疹0.78%、乏力0.42%、烦躁1.79%、呕吐0.92%、腹泻1.69%,都低于2%,全身和局部不良反应以轻度为主,且多在反应发生后3 d内恢复,无疫苗引起的严重不良事件,无致残及死亡事件发生。结论　冻干A+C群脑膜炎球菌多糖结合疫苗在3～71月龄的婴幼儿中大规模接种是安全的     

A+C群脑膜炎球菌多糖疫苗安全性评估

目的 评估A＋C群脑膜炎球菌多糖疫苗的安全性。方法 以A＋C群脑膜炎球菌多糖疫苗为观察组，伤寒Vi多糖疫苗为对照组，按整群随机分层配对的原则，将研究现场分为108个组群，观察组和对照组各分配54个组。对两组同时建立接种反应监测系统，按统一表格和方法对两组的接种反应进行监测、记录，并进行流行病学调查。结果 两组共接种34543人，其中A＋C群脑膜炎球菌多糖疫苗接种18167人，伤寒Vi疫苗接种16376人。A＋C群脑膜炎球菌多糖疫苗速发接种反应率为0．44‰，一般接种反应率为0．38％o；伤寒Vi疫苗速发接种反应率为0．79％，一般接种反应率为0．73％o；跟踪随访接种反应对象共1239人，其中接种A＋C群脑膜炎球菌多糖疫苗的771人，接种伤寒Vi疫苗的468人。接种后第1天，A＋C群脑膜炎球菌多糖疫苗组的局部反应发生率要明显高于伤寒Vi疫苗（X^2。=13．98，P=0．0002）；接种后第2—3天局部反应和全身反应的发生率，两组差异无统计学意义；两组各自接种人群和未接种人群发热发生率的差异无统计学意义，两组已接种人群的发热发生率差异也无统计学意义；两组均未发现严重反应。结论 A＋C群脑膜炎球菌多糖疫苗与伤寒Vi疫苗均可在不同年龄组人群开展大规模接种，局部及全身接种反应轻微，接种反应率低，有良好的安全性。     

Safety and immunogenicity of a novel multiple antigen pneumococcal vaccine in adults: A Phase 1 randomised clinical trial

BackgroundPneumococcal vaccines, combining multiple protein antigens, provide an alternative approach to currently marketed vaccines and may provide broader protection against pneumococcal disease. This trial evaluated the safety and immunogenicity of a novel vaccine candidate PnuBioVax in healthy young adults.MethodsIn a Phase 1 double-blind study, 36 subjects (18–40 years) were randomised to receive 3 doses of PnuBioVax, 28 days apart, at one of three dose levels (50, 200, 500 µg) or placebo. Safety assessments included rates of emergent adverse events (AEs), injection site and systemic reactions. Immunogenicity endpoints included antibody titre against PnuBioVax and selected pneumococcal antigens.ResultsIn the placebo (n = 9) and PnuBioVax (n = 27) vaccinated subjects, there were 15 and 72, reported TEAEs, respectively. The majority of TEAEs were classified as common vaccine related AEs. There were no serious AEs. Common vaccine-related AEs occurred in 13 PnuBioVax (48%) and 2 placebo (22%) subjects and were all headaches (mild and moderate). Injection site reactions, mostly pain and tenderness (graded mild or moderate) were reported, in particular in the 200 µg and 500 µg PnuBioVax groups. There were no clinically significant changes in vital signs, ECG or blood chemistries. Subjects receiving the higher dose (200 and 500 μg) demonstrated a greater fold increase in IgG titre compared with the starting dose (50 μg) or the placebo group. The fold-increase was statistically significantly higher for 200 and 500 µg PnuBioVax vs 50 µg PnuBioVax and placebo at each timepoint post-immunisation. Most subjects receiving 200 and 500 µg PnuBioVax demonstrated a ≥2-fold increase in antibody against pneumolysin (Ply), Pneumococcal surface antigen (PsaA), PiaA (Pneumococcal iron acquisition), PspA (Pneumococcal surface protein A) and pilus proteins (RrgB and RrgA).ConclusionsAll dose levels were considered safe and well tolerated. There was a statistically significant increase in anti-PnuBioVax IgG titres at the 200 and 500 µg dose levels compared to 50 µg and placebo. Trial registration number: NCT02572635 https://www.clinicaltrials.gov.     

Development of a synthetic Vi polysaccharide vaccine for typhoid fever

Typhoid fever remains a serious public health problem with a high impact on toddlers and young children. Vaccines against the Vi capsular polysaccharide are efficacious against typhoid fever demonstrating that antibodies against Vi confer protection. The currently licensed Vi typhoid vaccines have however limited efficacy and are manufactured by a complex process from wild-type bacteria. Due to these inherent issues with the current vaccines, an alternative vaccine based on an O-acetylated high molecular weight (HMW) polygalacturonic acid (GelSite-OAc™) was generated. The HMW polygalacturonic acid shares the same backbone as the Vi polysaccharide of Salmonella Typhi. The GelSite-OAc™ has a high molecular weight (>1 × 10⁶ Da) and a high degree of O-acetylation (DOAc) (>5 μmole/mg), both exceeding the potency specifications of the current Vi vaccine. Studies in Balb/c mice demonstrated that GelSite-OAc™ was highly immunogenic, inducing a strong antigen-specific antibody response in a DOAc- and dose-dependent manner which was comparable to or higher than those induced by the licensed Vi vaccine. Importantly, the GelSite-OAc™ was shown to be fully protective in mice against lethal challenge with Salmonella Typhi. Furthermore, the GelSite-OAc™ demonstrated a boosting effect or memory response, exhibiting a >2-fold increase in antibody levels upon the second immunization with either GelSite-OAc™ or the Vi vaccine. This novel boosting effect is unique among polysaccharide antigens and potentially makes GelSite-OAc™ effective in people under 2 years old. Together these results suggest that the GelSite-OAc™ could be a highly effective vaccine against Salmonella Typhi.     

A Japanese study to assess immunogenicity and safety of a typhoid Vi polysaccharide vaccine

BackgroundAlthough typhoid fever is rare in Japan, imported cases have been reported occasionally in travelers returning from endemic areas. To achieve licensing of a typhoid Vi polysaccharide vaccine (Typhim Vi^®) and make it widely available in Japan, this study was conducted at the request of the Japanese Ministry of Health Labor and Welfare to assess the immunogenicity and safety of this vaccine when given as a single dose (the recommended schedule of administration) in a Japanese population.MethodsIn this multi-center, open-label, non-comparative, intervention study performed in Japan, 200 healthy volunteers (188 adults [≥18 years of age], 7 adolescents [12–17 years of age] and 5 children [2–11 years of age]) were administered Typhim Vi^®. Immunogenicity was assessed 28 days after vaccinations using an ELISA method of anti-Vi antibody detection. A 4-fold increase in anti-Vi titer was considered as the threshold for seroconversion for anti-Vi antibodies. Safety was assessed up to 28 days following vaccination.ResultsOverall, 92.0% (95% confidence interval [CI]: 87.3–95.4%) of participants achieved seroconversion 28 days after a single dose of typhoid Vi polysaccharide vaccine. GMTs of Vi antibody titers increased from 6.6 (95% CI: 5.8–7.4) prior to vaccination to 157.3 (95% CI: 135.1–183.2) on Day 28 after vaccination. The geometric mean of individual anti-Vi antibody titer ratios (Day 28/Day 0) was 23.9 (95% CI: 20.3–28.3). There were no immediate adverse events and no adverse events led to the discontinuation of participants from the study. Across all age groups, pain and myalgia were the most frequently reported injection site and systemic reactions, respectively. Most of these reactions were mild in intensity and resolved within 7 days.ConclusionsA single dose of typhoid Vi polysaccharide vaccine, Typhim Vi^®, demonstrated good safety and immunogenicity profile in a Japanese population.     

Duration of Vi antibodies in participants vaccinated with Typhim Vi (Typhoid Vi polysaccharide vaccine) in an area not endemic for typhoid fever

After a single injection of Typhim Vi^® (typhoid Vi polysaccharide vaccine), serum antibody concentrations were monitored for 3 years in 37 adults who resided where typhoid fever was not endemic. Anti-Vi antibody concentrations declined progressively during the study, to levels that support the current US recommendation for revaccination every 2 years.     

Rethinking results from the Japanese 23-valent pneumococcal polysaccharide vaccine randomized clinical trial

We review a previously published randomized clinical trial of 23-valent pneumococcal polysaccharide vaccine (PPSV23) that has been used extensively globally to support PPSV23 use among adults. We argue that serious issues with internal and external validity exist that affect the usefulness of these data when evaluating pneumococcal vaccines for the general adult population. As one example of internal data inconsistency, the values reported for the percent of all pneumonia cases due to pneumococcus and the vaccine efficacy (VE) for all cause pneumonia are mutually inconsistent, even based on unrealistically high values for PPSV23 VE against vaccine serotypes and the proportion of pneumococcal pneumonias due to vaccine serotypes.     

Scalable production and immunogenicity of a cholera conjugate vaccine

There is a need to develop cholera vaccines that are protective in young children under 5 years of age, which induce long-term immunity, and which can be incorporated into the Expanded Programme of Immunization (EPI) in cholera-endemic countries. The degree of protection afforded by currently available oral cholera vaccines (OCV) to young children is significantly lower than that induced by vaccination of older vaccine recipients. Immune responses that protect against cholera target the O-specific polysaccharide (OSP) of Vibrio cholerae, and young children have poor immunological responses to bacterial polysaccharides, which are T cell independent antigens. To overcome this, we have developed a cholera conjugate vaccine (CCV) containing the OSP of V. cholerae O1, the main cause of endemic and epidemic cholera. Here, we describe production of CCV through a scalable manufacturing process and preclinical evaluation of immunogenicity in the presence and absence of aluminum phosphate (alum) as an adjuvant. The vaccine displays V. cholerae O1 Inaba OSP in sun-burst display via single point attachment of core oligosaccharide to a recombinant tetanus toxoid heavy chain fragment (rTTHc). Two different pilot-scale production batches of non-GMP CCV were manufactured and characterized in terms of physico-chemical properties and immunogenicity. In preclinical testing, the vaccine induced OSP- and lipopolysaccharide (LPS)-specific IgG and IgM responses, vibriocidal responses, memory B cell responses, and protection in a V. cholerae O1 challenge model. The addition of alum to the administered vaccine increased OSP-specific immune responses. These results support evaluation of CCV in humans.     

Long-term impact of pneumococcal polysaccharide vaccination on nasopharyngeal carriage in children previously vaccinated with various pneumococcal conjugate vaccine regimes

Previously, the Fiji Pneumococcal Project (FiPP) evaluated reduced dose immunization schedules that incorporated pneumococcal protein conjugate and/or polysaccharide vaccine (PCV7 and 23vPPV, respectively). Immune hyporesponsiveness was observed in children vaccinated with 23vPPV at 12 months of age compared with children who did not receive 23vPPV.Here we assess the long-term impact of 23vPPV vaccination on nasopharyngeal carriage rates and densities of Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus and Moraxella catarrhalis. Nasopharyngeal swabs (n = 194) were obtained from healthy children who participated in FiPP (now aged 5–7 years). S. pneumoniae were isolated and identified by standard culture-based methods, and serotyped using latex agglutination and the Quellung reaction. Carriage rates and densities of S. pneumoniae, H. influenzae, S. aureus and M. catarrhalis were determined using real-time quantitative PCR.There were no differences in the rate or density of S. pneumoniae, H. influenzae or M. catarrhalis carriage by PCV7 dose or 23vPPV vaccination in the vaccinated participants overall. However, differences were observed between the two main ethnic groups: Fijian children of Indian descent (Indo-Fijian) were less likely to carry S. pneumoniae, H. influenzae and M. catarrhalis, and there was evidence of a higher carriage rate of S. aureus compared with indigenous Fijian (iTaukei) children. Polysaccharide vaccination appeared to have effects that varied between ethnic groups, with 23vPPV vaccination associated with a higher carriage rate of S. aureus in iTaukei children, while there was a lower carriage rate of S. pneumoniae associated with 23vPPV vaccination in Indo-Fijian children.Overall, polysaccharide vaccination had no long-term impact on pneumococcal carriage, but may have impacted on S. aureus carriage and have varying effects in ethnic groups, suggesting current WHO vaccine schedule recommendations against the use of 23vPPV in children under two years of age are appropriate.     

Safety,tolerability, and immunogenicity of 15-valent pneumococcal conjugate vaccine in healthy adults

BackgroundPneumococcal disease remains an important health priority despite successful implementation of pneumococcal conjugate vaccines (PCVs) in infant immunization programs, mainly due to the emergence of diseases caused by serotypes not included in licensed PCVs. A 15-valent pneumococcal conjugate vaccine (PCV-15) containing the 7 serotypes (4, 6B, 9V, 14, 18C, 19F, and 23F) included in licensed PCV-7 available at study initiation plus 8 additional serotypes (1, 3, 5, 6A, 7F, 19A, 22F, 33F) was developed and evaluated in healthy adults 18–45 years of age.MethodsSixty subjects received one dose of PCV-15 or PCV-7. Injection-site and systemic adverse events (AEs) were collected for 14-days postvaccination and serious AEs were collected for 30-days postvaccination. Safety laboratory tests (hematology, chemistry, and urinalysis) were evaluated prior to vaccination and 14-days postvaccination. Serotype-specific IgG and opsonophagocytic killing activity (OPA) responses to 15 serotypes included in PCV-15 were measured immediately prior to vaccination and 30-days postvaccination.ResultsAE incidences were comparable between vaccine groups although numerically higher frequencies of erythema (33.3% versus 13.3%), swelling (50.0% versus 23.3%), and myalgia (63.3% versus 36.7%) were reported among PCV-15 versus PCV-7 recipients. Majority of AEs, irrespective of vaccine received, were transient and of mild-to-moderate intensity. No clinically significant differences were observed when comparing AE duration and severity. No laboratory abnormalities, vaccine-related SAEs or discontinuations from the study due to AEs were reported. IgG concentrations for the shared serotypes substantially increased postvaccination at comparable levels between recipients of PCV-15 and PCV-7. Substantial increases in antibody (IgG and OPA) responses to 8 serotypes unique to PCV-15 were observed in PCV-15 recipients. Slight increases to 2 serotypes unique to PCV-15, serotypes 6A and 19A, were also noted in PCV-7 recipients.ConclusionPCV-15 displays an acceptable safety profile and induces IgG and OPA responses to all serotypes included in the vaccine.     

Evaluation of impact of 23 valent pneumococcal polysaccharide vaccine following 7 valent pneumococcal conjugate vaccine in Australian Indigenous children

BackgroundHigh incidence and serotype diversity of invasive pneumococcal disease (IPD) in Indigenous children in remote Australia led to rapid introduction of 7-valent conjugate pneumococcal vaccine (7vPCV) at 2, 4 and 6 months in 2001, followed by 23-valent polysaccharide pneumococcal vaccine (23vPPV) in the second year of life. All other Australian children were offered 3 doses of 7vPCV without a booster from 2005. This study evaluated the impact of the unique pneumococcal vaccine schedule of 7vPCV followed by the 23vPPV booster among Indigenous Australian children.MethodsChanges in IPD incidence derived from population-based passive laboratory surveillance in Indigenous children <5 years eligible for 23vPPV were compared to non-Indigenous eligible for 7vPCV only from the pre-vaccine introduction period (Indigenous 1994–2000; non-Indigenous 2002–2004) to the post-vaccine period (2008–2010 in both groups) using incidence rate ratios (IRRs) stratified by age into serotype groupings of vaccine (7v and 13vPCV and 23vPPV) and non-vaccine types. Vaccine coverage was assessed from the Australian Childhood Immunisation Register.ResultsAt baseline, total IPD incidence per 100,000 was 216 (n = 230) in Indigenous versus 55 (n = 1993) in non-Indigenous children. In 2008–2010, IRRs for 7vPCV type IPD were 0.03 in both groups, but for 23v-non7v type IPD 1.2 (95% CI 0.8–1.8) in Indigenous versus 3.1 (95% CI 2.5–3.7) in non-Indigenous, difference driven primarily by serotype 19A IPD (IRR 0.6 in Indigenous versus 4.3 in non-Indigenous). For non-7vPCV type IPD overall, IRR was significantly higher in those age-eligible for 23vPPV booster compared to those younger, but in both age groups was lower than for non-Indigenous children.ConclusionThese ecologic data suggest a possible “serotype replacement sparing” effect of 23vPPV following 7vPCV priming, especially for serotype 19A with supportive evidence from other immunogenicity and carriage studies. Applicability post 10vPCV or 13v PCV priming in similar settings would depend on local serotype distribution of IPD.     

In a randomized,double-blinded,placebo-controlled trial,the single oral dose typhoid vaccine,M01ZH09, is safe and immunogenic at doses up to 1.7 × 10 colony-forming units

M01ZH09, S. Typhi (Ty2ΔaroCΔssaV) ZH9, is a single oral dose typhoid vaccine with independently attenuating deletions. A phase II randomized, double-blind, placebo-controlled, dose-escalating trial evaluated the safety and immunogenicity of M01ZH09 to 1.7 × 10¹⁰ colony-forming units (CFU). 187 Healthy adults received vaccine or placebo in four cohorts. Serologic responses and IgA ELISPOT were measured. At all doses, the vaccine was well tolerated and without bacteremias. One subject had a transient low-grade fever. 62.2–86.1% of subjects seroconverted S. Typhi-specific LPS IgG and 83.3–97.4% IgA; 92.1% had a positive S. Typhi LPS ELISPOT. M01ZH09 is safe and immunogenic up to 1.7 × 10¹⁰ CFU. Efficacy testing of this single-dose oral typhoid vaccine is needed.     

ACYW135群脑膜炎球菌多糖结合破伤风毒素疫苗免疫学效果的Meta分析

目的 评价ACYW135群脑膜炎球菌多糖结合破伤风毒素疫苗(MPCV-ACYW135-TT)的免疫学效果.方法 检索National Center for Biotechnology Information (NCBI)、Cochrane协作网图书馆、中国生物医学文献数据库、中国期刊全文数据库和万方全文数据库,将有关评价MPCV-ACYW135免疫学效果的随机对照试验(RCT)的研究纳入分析.以接种疫苗1个月后产生的血清杀菌活性(SBA)抗体阳转率(PRR)和几何平均滴度(GMT)作为结局指标,合并不同研究中试验组与对照组间的PRR和GMT的率差(RD)或标准化均数差(SMD).使用RevMan5.1软件进行Meta分析.结果 共纳入13篇文献:有9篇比较了MPCV-ACYW135-TT和ACYW135群脑膜炎球菌多糖疫苗(MPV-ACYW135)之间免疫学效果差异,4篇比较了MPCV-ACYW135-TT和C群脑膜炎球菌多糖结合白喉毒素变异体197疫苗(MPCV-C-CMR197)之间免疫学效果差异.相比于MPV-A-CYW135;受试者在接种MPCV-ACYW135-TT后产生的针对A、C、Y和W135这4个血清型抗体PRR的RD在0.03～0.15之间;产生的针对A、Y和W135这3个血清型抗体GMT的SMD在0.33～1.22之间.1～2岁组幼儿在接种MPCV-ACYW135-TT后产生的针对C群抗体GMT与接种MPCV-C-CMR197差异无统计学意义(H＞0.05).结论 MPCV-ACYW135-TT与其他已上市应用的脑膜炎球菌疫苗有相似的免疫效果.