Phase 1 safety and immunogenicity trial of the Plasmodium falciparum blood-stage malaria vaccine AMA1-C1/ISA 720 in Australian adults

A Phase 1 trial was conducted in malaria-naïve adults to evaluate the recombinant protein vaccine apical membrane antigen 1-Combination 1 (AMA1-C1) formulated in Montanide^® ISA 720 (SEPPIC, France), a water-in-oil adjuvant. Vaccinations were halted early due to a formulation issue unrelated to stability or potency. Twenty-four subjects (12 in each group) were enrolled and received 5 or 20 μg protein at 0 and 3 months and four subjects were enrolled and received one vaccination of 80 μg protein. After first vaccination, nearly all subjects experienced mild to moderate local reactions and six experienced delayed local reactions occurring at Day 9 or later. After the second vaccination, three subjects experienced transient grade 3 (severe) local reactions; the remainder experienced grade 1 or 2 local reactions. All related systemic reactogenicity was grade 1 or 2, except one instance of grade 3 malaise. Anti-AMA1-C1 antibody responses were dose dependent and seen following each vaccination, with mean antibody levels 2–3 fold higher in the 20 μg group compared to the 5 μg group at most time points. In vitro growth-inhibitory activity was a function of the anti-AMA1 antibody titer. AMA1-C1 formulated in ISA 720 is immunogenic in malaria-naïve Australian adults. It is reasonably tolerated, though some transient, severe, and late local reactions are seen.     

A phase 1 trial of PfCP2.9: an AMA1/MSP1 chimeric recombinant protein vaccine for Plasmodium falciparum malaria

Apical Membrane Antigen 1 (AMA1) and Merozoite Surface Protein 1 (MSP1) were produced as a recombinant fusion protein and formulated with the adjuvant Montanide ISA 720 with the aim of replicating the structure present in the parasite protein. A previous trial with this construct demonstrated the vaccine was safe and immunogenic but was associated with injection site reactogenicity. This Phase 1a dose-escalating, double blind, randomized, controlled trial of PfCP2.9/Montanide ISA 720 was conducted to evaluate alternative dose levels and vaccination schedules, with a pre-formulated vaccine that had undergone more in-depth and frequent quality control and stability analysis. The trial was conducted in seventy healthy Chinese malaria-na?ve volunteers between January 2006 and January 2007. The objective was to assess the safety, reactogenicity and immunogenicity of 5, 20 and 50microg of PfCP2.9/ISA 720 under 2 different schedules. The most common adverse event was injection site tenderness (53%). The frequency and severity of adverse events was similar in both vaccination schedules. Antibody responses were induced and remained elevated throughout the study in volunteers receiving vaccine (p<0.001). Although high antibody titers as measured by ELISA to the PfCP2.9 immunogen were observed, biological function of these antibodies was not reflected by the in vitro inhibition of parasite growth, and there was limited recognition of fixed parasites in an immunofluorescence assay. At all three dose levels and both schedules, this formulation of PfCP2.9/ISA 720 is well tolerated, safe and immunogenic; however no functional activity against the parasite was observed.     

Intradermal recombinant hepatitis B vaccine for healthcare workers who fail to respond to intramuscular vaccine.

OBJECTIVE: To study the humoral immune responses, safety, and tolerability of intradermal recombinant hepatitis B vaccination in healthcare workers (HCWs) nonresponsive to previous repeated intramuscular vaccination. DESIGN: An open, prospective, before-after trial. SETTING: A tertiary referral hospital and surrounding district health service in Queensland, Australia. PARTICIPANTS: Hospital and community HCWs nonresponsive to previous intramuscular hepatitis B vaccination. METHODS: Intradermal recombinant hepatitis B vaccine was administered every second week for a maximum of 4 doses. Hepatitis B surface antibody (anti-HBs) responses were assessed 2 weeks after each dose. RESULTS: Protective anti-HBs levels developed in 17 (94%) of 18 study subjects. Three doses resulted in seroconversion of all responding subjects and the highest geometric mean antibody concentration. The vaccine was well tolerated. CONCLUSION: More than 90% of previously nonresponsive HCWs responded to intradermal recombinant hepatitis B vaccine with protective anti-HBs levels.     

Clinical trial of the intradermal administration of hepatitis B vaccine produced at the Department of Medical Research, Myanmar

A total of 280 apparently healthy volunteers were screened for hepatitis B (HB) markers out of which 49 subjects (17.5%) were positive for HB surface antigen (HBsAg) and 82 (29.3%) were positive for antibody to HBsAg (anti-HBs). Three doses of DMR-HB vaccine, 0.15 ml per dose were administered to 95 subjects, who were serologically negative for both HB markers. The vaccination was given by the intradermal route on the flexor surface of the left forearm, at 1 month intervals according to the 0, 1 and 2 months schedule. The subjects were carefully monitored to record any adverse reaction of the vaccine. Blood specimen was collected from each subject, 1 month after the second and third vaccinations, to determine the anti-HBs antibody response to the vaccine. The study results showed that local pain was the only side effect noted and protective antibodies (anti-HBs) were detected in 69 (72.6%) of the vaccinees after the second dose of the vaccine and 89 (93.6%) after the third dose of the vaccine. Thus the intradermal route, which would require approximately one-seventh of the standard dose, would be suitable for use in certain groups such as high risk adults, when the cost of the vaccine is the inhibiting factor for routine or mass vaccination.     

A+C群脑膜炎球菌多糖疫苗接种反应与血清学观察

目的观察国产A C脑膜炎多糖疫苗(A C疫苗)的接种反应和免疫原性。方法以A C疫苗为观察苗、伤寒Vi多糖疫苗(Vi疫苗)为对照苗,采样用整群随机对照的临床试验方法,确定观察人群和对照人群。在已接种的两组人群中,采取整群分层抽样的方法抽取接种反应观察对象,并进行连续3天随访以观察接种反应。采集部分A C疫苗接种对象免前、免后血标本,检测血清抗体IgG4倍增长情况。结果共随访接种反应观察对象1239人,其中接种流脑A C疫苗的771人、接种伤寒Vi疫苗的468人。A C疫苗接种后第1天局部反应发生率为15.06%,第2天的为0.13%,第3天的为0;接种后第1天全身反应的发生率为1.16%,第2天为0.39%和第3天为0.13%。除接种后第1天A C疫苗的局部反应发生率要明显高于Vi疫苗的外,接种后2天、3天的局部反应和第1、2、3天全身反应的发生率,A C疫苗和Vi疫苗无显著性差异。共采集A C疫苗接种对象免前、免后血标本各100份,抗C群脑膜炎球菌抗体4倍增长率达到94%,抗A群脑膜炎球菌抗体仅达到62%。结论A C疫苗和伤寒Vi多糖疫苗一样,接种反应轻微,安全性好;抗C群脑膜炎球菌抗体免疫应答良好。接种前人群血清抗A群脑膜炎球菌抗体平均浓度比抗C群的高2.6倍,抗A群脑膜炎球菌抗体4倍增长率低可能与本底抗A群脑膜炎球菌抗体水平高有关。     

High levels of antibody in adults three years after vaccination with a reduced antigen content diphtheria-tetanus-acellular pertussis vaccine

There is increasing interest in prevention of pertussis in adults by vaccination, but little is known about the duration of the antibody response to pertussis, diphtheria or tetanus in reduced antigen content vaccines formulated for adult use. Follow-up of a clinical trial including 550 adults comparing responses to reduced antigen content diphtheria-tetanus-acellular pertussis (dTpa) vaccine, or a licensed Td vaccine, provided the opportunity to evaluate this. Blood samples were collected at 0, 1, 12, 24 and 36 months following vaccination; of the original cohort of 550, 387 subjects (dTpa group N=310, Td+pa group N=77) were tested at month 36. Following a decrease in antibody levels against all vaccine antigens between one and 24 months following vaccination, levels stabilized during the third year, remaining higher at 36 months than pre-vaccination for all vaccine antigens. In particular, more than 90% of subjects remained seropositive for pertussis toxin and pertactin antibodies at 36 months after vaccination, suggesting ongoing protection against pertussis. Adult-formulated dTpa vaccines could replace Td for routine booster vaccination of older individuals.     

A rift Valley fever vaccine trial. I. Side effects and serologic response over a six-month follow-up

A formalin-inactivated Rift Valley fever vaccine, originally produced in primary monkey kidney cells, has been used to protect laboratory workers. A trial of a modified vaccine, newly formulated in well-characterized diploid fetal rhesus lung cells, was conducted with 114 men aged 19--24 years. Of the 107 subjects who received up to three injections of 0.1 to 1 ml vaccine (an additional seven received a placebo) one had a local hypersensitivity-type reaction and another a generalized urticarial syndrome. Both cases had a prior history of hypersensitivity states. No pyrogenicity was detected and only insignificant systemic reactions were recorded. Mild and transient local reactions ranged from 5% at the lowest dose level to 43% at the highest. Serologic response, as assessed by plaque reduction neutralizing antibody titers, was dose dependent. Within a single vaccine lot tested at multiple dose levels, peak (day 42) geometric mean titers ranged from 48 (at 0.1 ml x 3) to 436 (at 1.0 ml x 3). Reciprocal titers of greater than or equal to 40 are considered to be protective. Comparison of three lots at the 0.5 ml level indicated between lot variability, though this was not statistically significant. A sharp decline in antibody titers was observed in all vaccination groups by day 84; six months after vaccination apparently protective antibody titers were present only in groups that received 1 ml x 3 and 0.5 ml x 3 of the most antigenic lot of vaccine. These results suggest that 1) the vaccine is generally nonreactogenic, but individuals with a prior history of hypersensitivity states should be observed for allergic side effects; 2) existing vaccine supplies cannot be extended by using lower dose levels without a lower and less sustained serologic response; 3) a booster dose is necessary six months or more following the primary series; 4) although the current TSI-GSD-200 vaccine is immunogenic, a more potent vaccine is needed.     

国产流行性感冒病毒裂解疫苗上市后的安全性及免疫原性评价

目的评价国产流行性感冒裂解疫苗上市后的安全性与免疫原性。方法 2011年8~10月在河南省长葛、禹州和登封开展了多中心、随机、对照试验。6 171名观察对象随机分配到接种组(3 083人)和对照组(3 088人)。接种组每人接种一剂疫苗,对照组不接受任何处理,比较两组研究对象免疫后28 d不良反应发生率。在接种组随机抽取599人作为免疫效果评估对象,在免疫前和免疫后28 d,采用微量血凝抑制(HI)试验测定疫苗抗体。结果接种组全身和局部不良反应发生率分别为7.14%(220/3 083)和1.36%(42/3 083)。对照组全身不良反应发生率为1.17%(36/3 088),无局部不良反应发生。接种组全身和局部不良反应发生率均显著高于对照组(χ2=138.285,P<0.001;χ2=42.356,P<0.001)。接种组H1N1、H3N2及B型抗体阳转率分别为79.30%、82.80%和67.60%,抗体保护率分别为89.30%、98.30%和93.00%,GMT分别为1∶416、1∶796和1∶180。结论国产流行性感冒裂解疫苗具有良好的安全性和免疫原性,适宜推广应用。     

High levels of antibody in adults three years after vaccination with a reduced antigen content diphtheria-tetanus-acellular pertussis vaccine

There is increasing interest in prevention of pertussis in adults by vaccination, but little is known about the duration of the antibody response to pertussis, diphtheria or tetanus in reduced antigen content vaccines formulated for adult use. Follow-up of a clinical trial including 550 adults comparing responses to reduced antigen content diphtheria-tetanus-acellular pertussis (dTpa) vaccine, or a licensed Td vaccine, provided the opportunity to evaluate this. Blood samples were collected at 0, 1, 12, 24 and 36 months following vaccination; of the original cohort of 550, 387 subjects (dTpa group N = 310, Td + pa group N = 77) were tested at month 36. Following a decrease in antibody levels against all vaccine antigens between one and 24 months following vaccination, levels stabilized during the third year, remaining higher at 36 months than pre-vaccination for all vaccine antigens. In particular, more than 90% of subjects remained seropositive for pertussis toxin and pertactin antibodies at 36 months after vaccination, suggesting ongoing protection against pertussis. Adult-formulated dTpa vaccines could replace Td for routine booster vaccination of older individuals.     

Hepatitis B DNA vaccine induces protective antibody responses in human non-responders to conventional vaccination

A novel DNA vaccine against hepatitis B virus was administered intraepidermally by particle-mediated epidermal delivery (PMED) to 16 human subjects who demonstrated absent or non-sustainable responses to conventional hepatitis B vaccination. Eleven subjects received three doses of vaccine at 56-day intervals, and five subjects received only a single vaccination. Each dose of vaccine contained 4 microg of plasmid DNA encoding the hepatitis B surface antigen (HBsAg). The vaccine was safe and well tolerated. Remarkably, the DNA vaccine elicited antibody responses in 12 of the 16 subjects after a licensed subunit vaccine failed to induce a lasting response after >/=3 vaccinations. This study provides evidence in humans for protective immunogenicity of a particle-mediated DNA vaccine in subjects who have responded suboptimally to conventional vaccination.     

Plasmodium falciparum apical membrane antigen 1 vaccine elicits multifunctional CD4 cytokine-producing and memory T cells

The Plasmodium falciparum apical membrane antigen 1 (AMA1) is a leading vaccine candidate and was tested for safety and immunogenicity in human Phase I Clinical Trials. PBMC from vaccine recipients were analyzed by flow cytometric methods to determine the nature of T-cell responses and AMA1-reactive memory T cells. Both CD4 and CD8 T cells produced a number of cytokines following AMA1 re-stimulation, with IL-5-producing cells at the highest frequency, consistent with a Th2 bias. The relative frequency of multifunctional cells synthesizing Th1 cytokines IFN-γ, IL-2 and TNF-α changed after each vaccination. Interestingly, median fluorescence intensity measurements revealed that cells producing more than one cytokine contributed greater quantities of each cytokine than cell populations that produced each of the cytokines alone. AMA1 vaccination also elicited the development of memory cell populations, and both central and effector memory T cells were identified concurrently after the AMA1 vaccination. The detailed profile of multifunctional T-cell responses to AMA1 presented here will advance our ability to assess the immunogenicity of human malarial vaccines.     

Enhancement of functional antibody responses to AMA1-C1/Alhydrogel, a Plasmodium falciparum malaria vaccine, with CpG oligodeoxynucleotide

Apical membrane antigen 1 (AMA1) has been shown to be a promising malaria vaccine candidate. The multiallelic AMA1-C1 vaccine currently in Phase 1 trials in the US and Mali contains an equal mixture of the ectodomain portion of recombinant AMA1 from the FVO and 3D7 clones of Plasmodium falciparum, formulated on Alhydrogel. It is hoped that inclusion of a human-optimized CpG oligodeoxynucleotide (ODN) (CPG 7909) with our existing AMA1-C1/Alhydrogel vaccine will lead to a higher concentration of functional AMA1-C1 antibodies. Preclinical studies were performed in mice, rats and guinea pigs to assess the safety, immunogenicity and functionality of the immune response to AMA1-C1 with Alhydrogel + CPG 7909 compared to antigen with Alhydrogel alone. Day 42 mean anti-AMA1 ELISA titer values derived from individual animals were compared between Alhydrogel and Alhydrogel + CPG 7909 groups at each antigen dose for each species. Sera from Alhydrogel + CPG 7909 groups displayed significantly higher antibody titers (P < 0.025) than their comparable Alhydrogel alone group. Mouse IgG isotype analysis showed that AMA1-C1/Alhydrogel induced a predominately Th2 type response while AMA1-C1/Alhydrogel + CPG 7909 gave a mixed Th1/Th2 type response. When tested for functional activity by in vitro inhibition of parasite invasion, IgG isolated from serum pools of AMA1-C1/Alhydrogel + CPG 7909 animals was more effective against both FVO and 3D7 parasites than an equal concentration of IgG from animals receiving vaccines adjuvanted with Alhydrogel alone. These promising preclinical results have recently led to the start of a Phase 1 trial in the US.     

A randomized controlled phase 2 trial of the blood stage AMA1-C1/Alhydrogel malaria vaccine in children in Mali

A double blind, randomized, controlled Phase 2 clinical trial was conducted to assess the safety, immunogenicity, and biologic impact of the vaccine candidate Apical Membrane Antigen 1-Combination 1 (AMA1-C1), adjuvanted with Alhydrogel^®. Participants were healthy children 2–3 years old living in or near the village of Bancoumana, Mali. A total of 300 children received either the study vaccine or the comparator. No impact of vaccination was seen on the primary endpoint, the frequency of parasitemia measured as episodes >3000/μL/day at risk. There was a negative impact of vaccination on the hemoglobin level during clinical malaria, and mean incidence of hemoglobin <8.5 g/dL, in the direction of lower hemoglobin in the children who received AMA1-C1, although these differences were not significant after correction for multiple tests. These differences were not seen in the second year of transmission.     

流行性出血热双价灭活疫苗的安全性和免疫原性观察

目的　观察流行性出血热 (EHF)沙鼠肾细胞双价灭活疫苗的安全性和免疫原性。方法　以高发疫区现场青壮年为对象 ,基础免疫 3针 ,一年后加强 1针。采用间接免疫荧光试验、微量细胞病变中和试验检测接种后荧光抗体和中和抗体 ,重点观察部分接种者免疫后 72h内的全身体温反应和局部副反应。结果　基础免疫后 2周 ,荧光抗体阳转率及几何平均滴度 (GMT)分别为99 .0 4%、2 4.5 1± 2 .0 6 ;中和抗体阳转率及平均滴度对 76 118(Ⅰ型 )为 91.30 %、18.2 7± 2 .2 1,对UR(Ⅱ型 )为 88.41%、12 .47± 2 .16。基础免疫后 1年 ,荧光抗体阳转率下降为 37.34% ,中和抗体总阳转率近 80 %。加强后 2周 ,荧光抗体和中和抗体阳转率均为 10 0 % ,中和抗体滴度对Ⅰ型为 37.0 9±2 .2 4,对Ⅱ型为 32 .6 1± 2 .0 5。接种后全身体温反应发生率为 0 .46 % ,局部反应发生率为 1.98% ,未见严重副反应发生。结论　流行性出血热双价灭活疫苗近期免疫效果良好 ,接种副反应率低     

重组戊型肝炎疫苗应用于16~65岁人群的安全性及免疫原性研究

目的 评价长春生物制品研究所有限责任公司研制的重组戊型病毒性肝炎（戊肝）疫苗用于16~65周岁人群免疫的临床安全性与免疫原性。方法 先筛选出戊肝抗体阴性者作为试验目标人群,再采用单中心、随机、盲法、同类制品平行对照的试验设计,选择戊肝抗体阴性的16~65周岁健康受试者60人,按1：1的比例随机接种试验疫苗和阳性对照疫苗,免疫程序均为0,1,6月程序,记录每针次接种后28 d内的不良反应/事件发生情况。采集免疫接种前和全程免疫接种后1个月的血液标本,进行戊肝IgG浓度检测。结果 招募369名受试者,经筛查戊肝抗体阴性者有187人,最终入组60人。试验组和阳性对照组免疫接种后总体征集性不良反应发生率分别为43.33%和40.00%,严重程度以轻、中度为主,最常见接种部位和全身不良反应分别为疼痛和头痛,不良反应的发生在组间差异均无统计学意义（均有P>0.05）。免疫后试验组与阳性对照组戊肝抗体阳性率均达到100%,抗体几何平均浓度（geometric mean concentration,GMC）分别为72.53 U/ml和87.49 U/ml。结论 试验疫苗具有良好的安全性和免疫原性,可以开展Ⅱ期临床试验。     

Human therapeutic cocaine vaccine: safety and immunogenicity.

This randomized, double blind, placebo controlled, phase I clinical trial assessed the safety and immunogenicity of a therapeutic cocaine vaccine TA-CD in 34 former cocaine abusers: 8 at 13 microg active vaccine, 10 at 82 microg and 10 at 709 microg, with two additional subjects getting placebo in each cohort. All got intra-muscular injections at 0-2 months and were monitored for safety and antibody production for 3 months. Of the 34 subjects 27 completed the full course of three injections, of these, only 24 returned for the final scheduled visit at day 84. The vaccine was well-tolerated and had no serious drug-related adverse events, although three subjects at the highest dose experienced brief post injection twitching. Fifteen subjects on TA-CD therapeutic vaccine were followed for 1 year. Antibody levels were correlated with vaccine dose and number of injections. Anti-cocaine antibodies were detected after the second injection, peaked at 3 months and declined to baseline by 1 year. Thus, the therapeutic vaccine was well tolerated with dose related increases in antibody levels, and a high proportion of patients recruited into the study were retained.     

Failure of a killed Leishmania amazonensis vaccine against American cutaneous leishmaniasis in Colombia

We report the results of a double-blind, randomized, placebo-controlled clinical trial of a killed whole-cell Leishmania amazonensis candidate vaccine against American cutaneous leishmaniasis (CL) in Colombia. The trial subjects were 2597 healthy volunteers with negative leishmanin skin test (LST) selected from rural Colombian soldiers who were going to patrol endemic areas. They were randomized to receive either three doses of vaccine (n=1295) or placebo (n=1302) given at 20-day intervals. An active and passive case detection system was established to follow-up volunteers for 1 year after vaccination. Safety and efficacy of the vaccine were determined by comparing local and systemic adverse reactions after each dose and the incidence of parasitologically confirmed CL. In the vaccine and placebo groups 101 (7.7%) and 88 (6.8%) volunteers developed CL respectively. The vaccine was shown to be safe but offered no protection against CL caused by L. panamensis in the proposed vaccination schedule.     

A randomized and controlled Phase 1 study of the safety and immunogenicity of the AMA1-C1/Alhydrogel + CPG 7909 vaccine for Plasmodium falciparum malaria in semi-immune Malian adults

A double blind, randomized and controlled Phase 1 clinical trial was conducted to assess the safety and immunogenicity in malaria-exposed adults of the Plasmodium falciparum blood stage vaccine candidate Apical Membrane Antigen 1-Combination 1 (AMA1-C1)/Alhydrogel^® with and without the novel adjuvant CPG 7909. Participants were healthy adults 18–45 years old living in the village of Donéguébougou, Mali. A total of 24 participants received 2 doses one month apart of either 80 μg AMA1-C1/Alhydrogel^® or 80 μg AMA1-C1/Alhydrogel^® + 564 μg CPG 7909. The study started in October 2007 and completed follow up in May 2008. Both vaccines were well tolerated, with only mild local adverse events and no systemic adverse events judged related to vaccination. The difference in antibody responses were over 2-fold higher in the group receiving CPG 7909 for all time points after second vaccination and the differences are statistically significant (all p < 0.05). This is the first use of the novel adjuvant CPG 7909 in a malaria-exposed population.     

Reduced intradermal test dose of yellow fever vaccine induces protective immunity in individuals with egg allergy

The neutralising antibody response after the yellow fever vaccine (YF-17D) skin test was measured in 7 egg allergic persons in whom further vaccination was abandoned because of a strong local urticarial reaction to the YF-17D vaccine test dose. We found that this test dose of 0.1 mL of YF-17D vaccine was sufficient to induce a protective antibody response in all 7 subjects. Intradermal injection of 1/5th dose of the yellow fever vaccine appears to be sufficient, in non-allergic as well as allergic persons, and non-inferior to the subcutaneous full dose.     

Immunogenicity and safety of two live-attenuated tetravalent dengue vaccine formulations in healthy Australian adults

We conducted a Phase 1b study to evaluate the immunogenicity and safety of two live attenuated tetravalent dengue vaccines in healthy adult volunteers. After one injection, all subjects reported systemic reactions consistent with a mild dengue-like syndrome. Seven volunteers developed dengue 3 viraemia after vaccination. All subjects developed a neutralizing antibody response against serotype 3 with partial response against other serotypes. The trial was stopped early (after 10 subjects enrolled) due to formulation issues, which were related to the dengue 3 vaccine component. Managing viral interference and balancing attenuation to produce acceptable tetravalent immunogenicity with minimal reactogenicity may be a recurring problem for future multivalent live vaccines.