Vaccine In Healthy Adults Research Articles

Safety and immunogenicity of a seasonal trivalent inactivated split influenza vaccine: a phase I randomized clinical trial in healthy Serbian adults

ABSTRACTThis study was a phase I double-blind, randomized, placebo-controlled trial to evaluate the safety and immunogenicity of a Serbian-produced seasonal trivalent split, inactivated influenza vaccine in healthy adults. The vaccine was manufactured in eggs by the Torlak Institute of Virology, Vaccines and Sera, Belgrade, Serbia and contained A/H1N1, A/H3N2 and B viruses. The clinical trial took place at the Clinical Center of Serbia in Belgrade. Sixty healthy volunteers, aged 18–45 years, were enrolled in the trial. On the day of immunization, volunteers were randomly assigned to receive either a single dose of the trivalent seasonal influenza vaccine (15 μg of hemagglutinin per strain) or placebo (phosphate-buffered saline). Subjects were monitored for adverse events through a clinical history and physical examination, and blood was taken for testing at screening and on day 8 to assess vaccine safety. Serum samples obtained before and 21 days after immunization were tested for influenza antibody titers using hemagglutination-inhibition (HAI) and microneutralization (MN) tests. No serious adverse events were reported. Pain and tenderness at the injection site were the most commonly reported symptoms in both vaccine and placebo groups. Overall, serum HAI responses of fourfold or greater magnitude were observed to H1, H3, and B antigen in 80%, 75%, and 70% of subjects, respectively. Seroprotection rates as measured by HAI were also high (100%, 100% and 86.67%, respectively, for H1, H3 and B). Thus, Torlak's seasonal trivalent influenza vaccine was not associated with adverse events, was well-tolerated and immunogenic. It should be further evaluated in clinical trials to provide sufficient safety and immunogenicity data for licensing in Serbia.

Safety and immunogenicity of a mRNA rabies vaccine in healthy adults: an open-label, non-randomised, prospective, first-in-human phase 1 clinical trial

Vaccines based on mRNA coding for antigens have been shown to be safe and immunogenic in preclinical models. We aimed to report results of the first-in-human proof-of-concept clinical trial in healthy adults of a prophylactic mRNA-based vaccine encoding rabies virus glycoprotein (CV7201). We did an open-label, uncontrolled, prospective, phase 1 clinical trial at one centre in Munich, Germany. Healthy male and female volunteers (aged 18-40 years) with no history of rabies vaccination were sequentially enrolled. They received three doses of CV7201 intradermally or intramuscularly by needle-syringe or one of three needle-free devices. Escalating doses were given to subsequent cohorts, and one cohort received a booster dose after 1 year. The primary endpoint was safety and tolerability. The secondary endpoint was to determine the lowest dose of CV7201 to elicit rabies virus neutralising titres equal to or greater than the WHO-specified protective antibody titre of 0·5 IU/mL. The study is continuing for long-term safety and immunogenicity follow-up. This trial is registered with ClinicalTrials.gov, number NCT02241135. Between Oct 21, 2013, and Jan 11, 2016, we enrolled and vaccinated 101 participants with 306 doses of mRNA (80-640 μg) by needle-syringe (18 intradermally and 24 intramuscularly) or needle-free devices (46 intradermally and 13 intramuscularly). In the 7 days post vaccination, 60 (94%) of 64 intradermally vaccinated participants and 36 (97%) of 37 intramuscularly vaccinated participants reported solicited injection site reactions, and 50 (78%) of 64 intradermally vaccinated participants and 29 (78%) of 37 intramuscularly vaccinated participants reported solicited systemic adverse events, including ten grade 3 events. One unexpected, possibly related, serious adverse reaction that occurred 7 days after a 640 μg intramuscular dose resolved without sequelae. mRNA vaccination by needle-free intradermal or intramuscular device injection induced virus neutralising antibody titres of 0·5 IU/mL or more across dose levels and schedules in 32 (71%) of 45 participants given 80 μg or 160 μg CV7201 doses intradermally and six (46%) of 13 participants given 200 μg or 400 μg CV7201 doses intramuscularly. 1 year later, eight (57%) of 14 participants boosted with an 80 μg needle-free intradermal dose of CV7201 achieved titres of 0·5 IU/mL or more. Conversely, intradermal or intramuscular needle-syringe injection was ineffective, with only one participant (who received 320 μg intradermally) showing a detectable immune response. This first-ever demonstration in human beings shows that a prophylactic mRNA-based candidate vaccine can induce boostable functional antibodies against a viral antigen when administered with a needle-free device, although not when injected by a needle-syringe. The vaccine was generally safe with a reasonable tolerability profile. CureVac AG.

Persistence of immune responses to vaccine against haemorrhagic fever with renal syndrome in healthy adults aged 16–60 years: results from an open-label2-year follow-up study

Background: Approximately 2 million doses of vaccine against haemorrhagic fever with renal syndrome (HFRS) have been used annually in China. However, there were limited studies focused on persistence of immune responses to HFRS vaccine in healthy adults. A phase 4, multicentre, open trial has been undertaken to assess antibody persistence after HFRS vaccination of healthy adolescents and adults aged 16–60 years.Methods: The vaccine was administered as a three-dose series at 0, 2 weeks and 6 months, including two primary doses and one booster dose. Anti-hantavirus IgG antibodies were measured by enzyme-linked immunosorbent test (ELISA) pre-vaccination and 1.5, 7 and 24 months after the initial vaccination.Results: A total of 143 individuals aged 16–60 years were included. The median OD (range) values of IgG antibody were 0.005 (0.004–0.016), 0.116 (0.036–0.620), 0.320 (0.065–0.848) and 0.128 (0.011–0.649) pre-vaccination and at 1 month after the two primary doses, 1 month after the booster dose and 18 months after the booster dose. The positivity rate was 7.7%, 40.6%, 62.2% and 48.2%, respectively.Conclusions: The two primary doses could help healthy individuals to generate an immune response, and this three-dose series may be better than a two-dose regimen.

Safety and immunogenicity of an inactivated cell culture-derived H7N9 influenza vaccine in healthy adults: A phase I/II, prospective, randomized, open-label trial

BackgroundWe conducted a phase I/II clinical trial to evaluate the safety and immunogenicity of a Madin-Darby canine kidney (MDCK) cell-grown inactivated H7N9 influenza vaccine for pandemic preparedness purposes. MethodsBetween April 7, 2015 and May 27, 2016, healthy adults aged 20–60years were enrolled sequentially in phase I (n=40) and phase II (n=160) from three hospitals in Taiwan and randomized to receive 2 doses of whole-virus H7N9 vaccine (15 or 30μg hemagglutinin antigen (HA) with or without an aluminum hydroxide adjuvant) at 21-day intervals. Safety up to 180days and changes in hemagglutinin inhibition (HI) titers at 21days after each vaccination were determined. ResultsOf the 200 randomized subjects, 193 (96.5%) received 2 doses of the study vaccine and were included in the intention-to-treat analysis for safety, and 190 (95%) were included in the per-protocol analysis for immunogenicity. Most adverse events were mild and transient; no death or vaccine-related serious adverse events were reported. Overall, higher immune responses were observed in the groups administered with 30μgHA formulation than in the other two groups administered with 15μgHA formulation. The highest immune response was observed in subjects who received 2 doses of the adjuvanted vaccine containing 30μgHA with HI titer, seroprotection rate, seroconversion rate, and seroconversion factor of 36.2, 64.6%, 64.6% and 5.7, respectively. ConclusionsOur study demonstrated that the H7N9 influenza vaccine containing 30µgHA with aluminum hydroxide adjuvant was immunogenic and safe in adults aged 20–60years.CLINICALTRIALS.GOV identifier: NCT02436928.

Immunogenicity and safety of an AS03-adjuvanted H7N1 vaccine in healthy adults: A phase I/II, observer-blind, randomized, controlled trial

BackgroundH7 influenza strains have pandemic potential. AS03-adjuvanted H7N1 A/mallard/Netherlands/12/2000 split-virion vaccine formulations were evaluated as model H7-subtype vaccine and tested after H7N9 emerged in China, and caused severe human disease with high mortality. MethodsIn this phase I/II, observer-blind, randomized trial in US and Canada, 420 healthy adults (21–64years) were randomized to receive 1 of 4 H7N1 vaccine formulations (3.75 or 7.5μg hemagglutinin adjuvanted with either AS03A or AS03B), 15μg unadjuvanted H7N1 hemagglutinin, or saline placebo, given as 2-dose series. Immunogenicity was assessed using hemagglutination-inhibition (HI) and microneutralization (MN) assays, at day 42 (21days post-dose 2), month 6, and month 12 (HI only) for the per-protocol cohorts (398, 379 and 368 participants, respectively). Safety is reported up to month 12. ResultsBeneficial AS03 adjuvant effect was demonstrated. Committee for Medical Products for Human Use, and Center for Biologics Evaluation and Research (CBER) criteria were met for all adjuvanted formulations at day 42 (H7N1 HI assay); seroprotection (SPR) and seroconversion rates (SCR) were 88.5–94.8%, mean geometric increase (MGI) 19.2–34.9, and geometric mean titers (GMT) 98.3–180.7. Unadjuvanted H7N1 vaccine did not meet CBER criteria. In adjuvanted groups, antibody titers decreased over time; month 12 SPRs and GMTs were low (2.0–18.8% and 8.1–12.2). MN antibodies showed similar kinetics, with titers persisting at higher range than HI at month 6. All adjuvanted groups showed cross-reactivity against H7N9, with HI responses similar to H7N1.The most frequent solicited symptom in adjuvanted groups was injection site pain (71.2–86.7%); grade 3 solicited symptoms were infrequent. Nine participants reported 17 serious adverse events; none were considered causally related to vaccination. ConclusionsAdjuvanted H7N1 vaccine formulations had an acceptable safety profile and induced an antibody response after 2 doses with cross-reactivity to H7N9.ClinicalTrials.gov: NCT01934127

Stable emulsion (SE) alone is an effective adjuvant for a recombinant, baculovirus-expressed H5 influenza vaccine in healthy adults: A Phase 2 trial

BackgroundInfluenza A viruses of the H5 subtype have been identified as important targets for development of vaccines. Achievement of potentially protective antibody responses against pandemic strains has usually required the use of adjuvants. ObjectivesWe evaluated a candidate A/Indonesia/05/2005 (H5) vaccine generated by baculovirus expression of recombinant hemagglutinin (HA) protein with or without stable emulsion (SE) as an adjuvant. MethodsHealthy subjects 18–49years old were randomized (1:1:1:1) to receive two doses of rHA at 7.5ug per dose (no adjuvant), or 3.8ug, 7.5ug, or 15ug per dose formulated with 2% SE separated by 21days, and serum from day 0, 21, 42, and 201 assessed by hemagglutination-inhibition. Results341 subjects were enrolled in the study and 321 received two doses of vaccine. Vaccination was well tolerated in all groups. After two doses, seroconversion was noted in only 9% (95% confidence interval 4%, 17%) of recipients of unadjuvanted vaccine at 7.5ug, but in 70% (59%, 80%), 76% (65%, 85%), and 83% (73%, 91%) of those receiving adjuvanted vaccine at 3.8ug, 7.5ug, or 15ug respectively. ConclusionsStable emulsion alone is an effective adjuvant for rH5 vaccine in healthy adults. All three adjuvanted dose groups met the current criterion for seroconversion rate for pandemic vaccines. This dose-ranging study also identified a group (15ug per dose formulated with 2% SE) that met the criteria for both seroconversion and percentage of subjects achieving an HI antibody titer⩾40. These Phase 2 data support the further clinical development of SE adjuvanted Panblok H5.Clinical trial registration: NCT01612000.The protocol was approved by the relevant Institutional Review Board for each study site, and the study was conducted in accordance with the Declaration of Helsinki, International Conference of Harmonisation – Good Clinical Practice, and all applicable laws and regulations. All participants provided written informed consent before study procedures.

Hepatitis B Vaccine in Healthy Adults: Effect of Sex and Age, Two Protocols for Non-Responding Adults

Hepatitis B Vaccine in Healthy Adults: Effect of Sex and Age, Two Protocols for Non-Responding Adults

Safety and immunogenicity of a recombinant adenovirus type-5 vector-based Ebola vaccine in healthy adults in Sierra Leone: a single-centre, randomised, double-blind, placebo-controlled, phase 2 trial

A recombinant adenovirus type-5 vector-based vaccine expressing the glycoprotein of Ebola Zaire Makona variant showed good safety and immunogenicity in a phase 1 trial of healthy Chinese adults. We aimed to assess the safety and immunogenicity of this vaccine in healthy adults in Sierra Leone and to determine the optimal dose. We did a single-centre, randomised, double-blind, placebo-controlled, phase 2 clinical trial at Sierra Leone-China Friendship Hospital, Freetown, Sierra Leone. We recruited healthy adults aged 18-50 years who were HIV negative, had no history of Ebola virus infection, and had no previous immunisation with other Ebola vaccine candidates. Participants were sequentially enrolled and randomly assigned (2:1:1), by computer-generated block randomisation (block size of eight), to receive the high-dose vaccine (1·6 × 1011 viral particles), low-dose vaccine (8·0 × 1010 viral particles), or placebo (containing only vaccine excipients, with no viral particles). Participants, investigators, and study staff (except two study pharmacists) were masked from treatment allocation. The primary safety outcome was occurrence of solicited adverse reactions within 7 days of vaccination, analysed by intention to treat. The primary immunogenicity outcome was glycoprotein-specific antibody responses at days 14, 28, and 168 after vaccination, analysed in all vaccinated participants who had blood samples drawn for antibody tests. The trial is registered with the Pan African Clinical Trials Registry, number PACTR201509001259869, and is completed. During Oct 10-28, 2015, 500 participants were enrolled and randomly assigned to receive the high-dose vaccine (n=250), low-dose vaccine (n=125), or placebo (n=125). 132 (53%) participants in the high-dose group, 60 (48%) in the low-dose group, and 54 (43%) in the placebo group reported at least one solicited adverse reaction within 7 days of vaccination. Most adverse reactions were mild and self-limiting. Solicited injection-site adverse reactions were significantly more frequent in vaccine recipients (65 [26%] in high-dose group and 31 [25%] in low-dose group) than in those receiving placebo (17 [14%]; p=0·0169). Glycoprotein-specific antibody responses were detected from day 14 onwards (geometric mean titre 1251·0 [95% CI 976·6-1602·5] in low-dose group and 1728·4 [1459·4-2047·0] in high-dose group) and peaked at day 28 (1471·8 [1151·0-1881·8] and 2043·1 [1762·4-2368·4]), but declined quickly in the following months (223·3 [148·2-336·4] and 254·2 [185·0-349·5] at day 168). Geometric mean titres in the placebo group remained around 6·0-6·8 throughout the study period. Three serious adverse events (malaria, gastroenteritis, and one fatal asthma episode) were reported in the high-dose vaccine group, but none was deemed related to the vaccine. The recombinant adenovirus type-5 vector-based Ebola vaccine was safe and highly immunogenic in healthy Sierra Leonean adults, and 8·0 × 1010 viral particles was the optimal dose. Chinese Ministry of Science and Technology and the National Health and Family Planning Commission, Beijing Institute of Biotechnology, and Tianjin CanSino Biotechnology.

Induction of transcription factors, miRNAs and cytokines involved in T lymphocyte differentiation in BCG-vaccinated subjects.

The BCG vaccine induces a Th1 phenotype, which is essential for protection against Mycobacterium tuberculosis. However, the effects of BCG vaccination over time on the T helper subpopulation and the microRNAs involved in adulthood have not been studied. In the present study, we explored the involvement of microRNAs, transcription factors and multifunctional cytokines in BCG vaccination by examining their levels both before and after vaccination of healthy adults. Peripheral blood mononuclear cells were obtained at 0, 2 and 6 months after vaccination. Cells were cultured in the presence or absence of ESAT-6 and CFP-10 or M. tuberculosis filtrate. The expression levels of miRNAs and transcription factors were evaluated using qRT-PCR. Cytokine production in supernatants and serum samples was evaluated using ELISA. Multifunctional CD4+ T cells were analyzed using multiparametric flow cytometry. We observed a decrease in the expression levels of T-BET, GATA3 and FOXP3 at 2 months and miR-146a, miR-326 and miR-155 at 6 months after receiving the vaccine. In the supernatant, the production of IL-17 was increased after 6 months, with both stimuli. In contrast, IL-10, TNF-α and IFN-γ increased at 2 months. In the serum, high levels of IL-10 were found after 2 months compared to time 0 and 6 months. The production of multifunctional cells that expressed the cytokine profiles CD4+TNF-α+IFN-γ-IL-10-, CD4+TNF-α+IL-1IFN-γ-, CD4+IL-10+IFN-γ-TNF-α- and CD4+IL-17+IFN-γ- predominantly increased after 2 months with and without the stimulus. Correlation analysis revealed a negative association between FOXP3 and miR-155 (r=-0.5120, p=0.0176) and between IL-17 and miR-326 (r=-0.5832, p=0.0364). This study is the first to demonstrate roles for microRNAs, transcription factors and cytokines in the T helper differentiation lineage and to describe the possible mechanism by which their expression is modulated by the presence of the BCG vaccine in adulthood. In conclusion, our results suggest that the BCG vaccine induces a modulation in transcription factors and miRNAs with high production of multifunctional cells CD4+TNF-α+IL-10+IFN-γ-.

The cost-effectiveness of pneumococcal vaccination in healthy adults over 50: An exploration of influential factors for Belgium

BackgroundA recent trial demonstrated the 13 valent conjugate pneumococcal vaccine (PCV13) to be effective against invasive and non-invasive pneumococcal disease in healthy adults. PCV13 might therefore be considered as an alternative to the 23 valent polysaccharide vaccine (PPV23). AimTo explore the cost-effectiveness of vaccinating healthy adults over 50, with either PCV13 or PPV23 alone, or with a combined strategy using both PCV13 and PPV23. MethodsA static multi-cohort model was developed simulating the consequences of pneumococcal vaccination in adults over 50 from a health care payer's perspective, for different scenarios of duration of vaccine protection and serotype evolution. ResultsAt currently expected prices, PCV13 vaccination of healthy adults over 50 is unlikely to be cost-effective either compared with no vaccination or in combination with PPV23 versus PPV23 only. ConclusionFurther research is needed on vaccine efficacy of the combination strategy and of risk groups, as well as the duration of vaccine protection. Serotype evolutions under the influence of the childhood PCV program should be closely monitored.

Immunogenicity and Safety of Pandemic Influenza H5N1 Vaccines in Healthy Adults through Meta-Analysis

Background: There are sporadic cases and local outbreaks of H5N1 avian influenza virus worldwide every year. The World Health Organization (WHO) has paid close attention to the avian influenza epidemic trend. Avian influenza vaccines (AIV) are considered to be useful when an epidemic occurs. However, the use of AIV for humans is not yet widespread. Methods: This study assessed the immunogenicity and safety of pandemic influenza H5N1 vaccines with inactivated whole virus, split virus and subunit virus vaccines for healthy adults. We searched the databases of the Cochrane Central Register of Controlled Trials (CENTRAL), Medline, Excerpata Medica Database (EMBASE) and China National Knowledge Infrastructure (CNKI). The data from randomized trials regarding the immunogenicity and safety of AIV with or without different types of adjuvants for healthy adults (with an age range from 18 to 60 years) were collected. Results: According to this study, the most effective doses of H5N1 AIV ranged from 3.75 µg to 7.5 µg Hemagglutinin (HA) antigen. Aluminium adjuvants were administered with the same vaccine dose as a no-adjuvant group and induced the same immune effects. However, novel adjuvants (MF59 and AS03) were used with a smaller dose of vaccine than the no-adjuvant groups and successfully stimulated the body to produce more effective antibodies. Conclusion: All of the H5N1 AIV surveyed in this study were well tolerated without serious adverse reactions.

Safety and immunogenicity of a chimpanzee adenovirus-vectored Ebola vaccine in healthy adults: a randomised, double-blind, placebo-controlled, dose-finding, phase 1/2a study

The ongoing Ebola outbreak led to accelerated efforts to test vaccine candidates. On the basis of a request by WHO, we aimed to assess the safety and immunogenicity of the monovalent, recombinant, chimpanzee adenovirus type-3 vector-based Ebola Zaire vaccine (ChAd3-EBO-Z). We did this randomised, double-blind, placebo-controlled, dose-finding, phase 1/2a trial at the Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland. Participants (aged 18-65 years) were randomly assigned (2:2:1), via two computer-generated randomisation lists for individuals potentially deployed in endemic areas and those not deployed, to receive a single intramuscular dose of high-dose vaccine (5 × 10(10) viral particles), low-dose vaccine (2·5 × 10(10) viral particles), or placebo. Deployed participants were allocated to only the vaccine groups. Group allocation was concealed from non-deployed participants, investigators, and outcome assessors. The safety evaluation was not masked for potentially deployed participants, who were therefore not included in the safety analysis for comparison between the vaccine doses and placebo, but were pooled with the non-deployed group to compare immunogenicity. The main objectives were safety and immunogenicity of ChAd3-EBO-Z. We did analysis by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT02289027. Between Oct 24, 2014, and June 22, 2015, we randomly assigned 120 participants, of whom 18 (15%) were potentially deployed and 102 (85%) were non-deployed, to receive high-dose vaccine (n=49), low-dose vaccine (n=51), or placebo (n=20). Participants were followed up for 6 months. No vaccine-related serious adverse events were reported. We recorded local adverse events in 30 (75%) of 40 participants in the high-dose group, 33 (79%) of 42 participants in the low-dose group, and five (25%) of 20 participants in the placebo group. Fatigue or malaise was the most common systemic adverse event, reported in 25 (62%) participants in the high-dose group, 25 (60%) participants in the low-dose group, and five (25%) participants in the placebo group, followed by headache, reported in 23 (57%), 25 (60%), and three (15%) participants, respectively. Fever occurred 24 h after injection in 12 (30%) participants in the high-dose group and 11 (26%) participants in the low-dose group versus one (5%) participant in the placebo group. Geometric mean concentrations of IgG antibodies against Ebola glycoprotein peaked on day 28 at 51 μg/mL (95% CI 41·1-63·3) in the high-dose group, 44·9 μg/mL (25·8-56·3) in the low-dose group, and 5·2 μg/mL (3·5-7·6) in the placebo group, with respective response rates of 96% (95% CI 85·7-99·5), 96% (86·5-99·5), and 5% (0·1-24·9). Geometric mean concentrations decreased by day 180 to 25·5 μg/mL (95% CI 20·6-31·5) in the high-dose group, 22·1 μg/mL (19·3-28·6) in the low-dose group, and 3·2 μg/mL (2·4-4·9) in the placebo group. 28 (57%) participants given high-dose vaccine and 31 (61%) participants given low-dose vaccine developed glycoprotein-specific CD4 cell responses, and 33 (67%) and 35 (69%), respectively, developed CD8 responses. ChAd3-EBO-Z was safe and well tolerated, although mild to moderate systemic adverse events were common. A single dose was immunogenic in almost all vaccine recipients. Antibody responses were still significantly present at 6 months. There was no significant difference between doses for safety and immunogenicity outcomes. This acceptable safety profile provides a reliable basis to proceed with phase 2 and phase 3 efficacy trials in Africa. Swiss State Secretariat for Education, Research and Innovation (SERI), through the EU Horizon 2020 Research and Innovation Programme.

H7N9 live attenuated influenza vaccine in healthy adults: a randomised, double-blind, placebo-controlled, phase 1 trial

H7N9 avian influenza viruses characterised by high virulence and presence of mammalian adaptation markers have pandemic potential. Specific influenza vaccines remain the main defence. We assessed the safety and immunogenicity of an H7N9 live attenuated influenza vaccine (LAIV) candidate in healthy adult volunteers. We did a phase 1, double-blind, randomised, placebo-controlled trial in Saint Petersburg, Russia. Eligible participants were healthy adults aged 18-49 years. The participants were randomised 3:1 to receive live vaccine or placebo, according to a computer-generated randomisation scheme. Two doses of vaccine or placebo were administered intranasally 28 days apart, each followed by 7 day stays in hospital. Immune responses were assessed in nasal swabs, saliva, and serum specimens collected before and 28 days after each vaccine dose. The primary outcome was the safety profile. This trial is registered with ClinicalTrials.gov, number NCT02480101. Between Oct 21, 2014, and Oct 31, 2014, 40 adults were randomised, of whom 39 (98%) were included in the per-protocol analysis (29 in the vaccine group and ten in the placebo group). The frequency of adverse events did not differ between the vaccine and placebo groups. Seroconversion of neutralising antibodies was seen in 14 participants after the first vaccine dose (48%, 95% CI 29·4-67·5) and 21 after the second vaccine dose (72%, 52·8-87·3). Immune responses were seen in 27 of 29 recipients (93%, 95% CI 77·2-99·2). Adverse effects were seen in 19 (63%) vaccine recipients and nine (90%) placebo recipients after the first dose and in nine (31%) and four (40%), respectively, after the second dose. These effects were mainly local and all were mild. The H7N9 LAIV was well tolerated and safe and showed good immunogenicity. WHO.

English

Objective: To assess the safety and immunogenicity of Haemophilus influenzae type b/polyribosylribitol phosphate-Tetanus (Hib/PRP-T) liquid vaccine in healthy adults. Methods: An open label prospective intervention phase I study was conducted in Dr. Hasan Sadikin General Hospital from November to December 2010. Healthy adults aged 18−40 were eligible to participate. Participants received one dose of Hib/PRP-T liquid vaccine. Blood samples were taken before, 4 days and 1 month after vaccination. For a 28-day period following vaccination, solicited adverse events were collected in the subjects’ diary and assessed afterward. Results: Neither local reactions nor immediate systemic events were observed during a 30-minute period after immunization. There were no serious local or systemic reactions in this study. All of local and systemic reactions observed were slight, transient, self-limiting in time, without lasting for more than 72 hrs. after the administration of the vaccine, and resolved without any medical intervention. Hematologic and biochemical indices before and 4 days after vaccination showed in normal limits. All subjects (100%) reached protective levels of antibodies (seroprotectivity) against Hib. All subjects demonstrated antibodies performing high bactericidal activities 1 month after immunization. Conclusions: This study demonstrated that liquid Hib/PRP-T vaccine is highly immunogenic and have a beneficial safety when administered to healthy adults. Keywords: Adults, Hib vaccines, immunogenicity, safety DOI: 10.15850/ijihs.v3n2.584

Immunogenicity and safety of a tetravalent dengue vaccine in healthy adults in India: A randomized, observer-blind, placebo-controlled phase II trial

Dengue is a mosquito-borne viral disease that is endemic in India. We evaluated the immunogenicity and safety of recombinant, live-attenuated, tetravalent dengue vaccine (CYD-TDV) in Indian adults. In this observer-blind, randomized, placebo-controlled, Phase II study, adults aged 18–45 years were randomized 2:1 to receive CYD-TDV or placebo at 0, 6 and 12 months in sub-cutaneous administration. Immunogenicity was assessed using a 50% plaque reduction neutralization test (PRNT50) at baseline and 28 days after each study injection. 189 participants were enrolled (CYD-TDV [n = 128]; placebo, [n = 61]). At baseline, seropositivity rates for dengue serotypes 1, 2, 3 and 4 ranged from 77.0% to 86.9%. Seropositivity rates for each serotype increased after each CYD-TDV injection with a more pronounced increase after the first injection. In the CYD-TDV group, geometric mean titres (GMTs) were 2.38 to 6.11-fold higher after the third injection compared with baseline but remained similar to baseline in the placebo group. In the CYD-TDV group, the GMTs were 1.66 to 4.95-fold higher and 9.23 to 24.6-fold higher after the third injection compared with baseline in those who were dengue seropositive and dengue seronegative, respectively. Pain was the most commonly reported solicited injection site reaction after the first injection in both the CYD-TDV (6.3%) and placebo groups (4.9%), but occurred less frequently after subsequent injections. No serious adverse events were vaccine-related, no immediate unsolicited adverse events, and no virologically-confirmed cases of dengue, were reported during the study. The immunogenicity and safety of CYD-TDV was satisfactory in both dengue seropositive and seronegative Indian adults.

Lot-to-lot consistency of a tetravalent dengue vaccine in healthy adults in Australia: A randomised study

BackgroundThe recombinant yellow fever-17D-dengue virus, live, attenuated, tetravalent dengue vaccine (CYD-TDV) has undergone extensive clinical trials. Here safety and consistency of immunogenicity of phase III manufacturing lots of CYD-TDV were evaluated and compared with a phase II lot and placebo in a dengue-naïve population. MethodsHealthy 18–60 year-olds were randomly assigned in a 3:3:3:3:1 ratio to receive three subcutaneous doses of either CYD-TDV from any one of three phase III lots or a phase II lot, or placebo, respectively in a 0, 6, 12 month dosing schedule. Neutralising antibody geometric mean titres (PRNT50 GMTs) for each of the four dengue serotypes were compared in sera collected 28 days after the third vaccination—equivalence among lots was demonstrated if the lower and upper limits of the two-sided 95% CIs of the GMT ratio were ≥0.5 and ≤2.0, respectively. Results712 participants received vaccine or placebo and 614 (86%) completed the study; 17 (2.4%) participants withdrew after adverse events. Equivalence of phase III lots was demonstrated for 11 of 12 pairwise comparisons. One of three comparisons for serotype 2 was not statistically equivalent. GMTs for serotype 2 in phase III lots were close to each other (65.9, 44.1 and 58.1, respectively). ConclusionsPhase III lots can be produced in a consistent manner with predictable immune response and acceptable safety profile similar to previously characterised phase II lots. The phase III lots may be considered as not clinically different as statistical equivalence was shown for serotypes 1, 3 and 4 across the phase III lots. For serotype 2, although equivalence was not shown between two lots, the GMTs observed in the phase III lots were consistently higher than those for the phase II lot. As such, in our view, biological equivalence for all serotypes was demonstrated.

Antibody response to booster vaccination with tetanus and diphtheria in adults exposed to perfluorinated alkylates

Recent studies suggest that exposure to perfluorinated alkylate substances (PFASs) may induce immunosuppression in humans and animal models. In this exploratory study, 12 healthy adult volunteers were recruited. With each subject, serum-PFAS concentrations were measured and their antibody responses prospectively followed for 30 days after a booster vaccination with diphtheria and tetanus. The results indicated that serum-PFAS concentrations were positively correlated and positively associated with age and male sex. The specific antibody concentrations in serum were increased from Day 4 to Day 10 post-booster, after which a constant concentration was reached. Serum PFAS concentrations showed significant negative associations with the rate of increase in the antibody responses. Interestingly, this effect was particularly strong for the longer-chain PFASs. All significant associations remained significant after adjustment for sex and age. Although the study involved a small number of subjects, these findings of a PFAS-associated reduction of the early humoral immune response to booster vaccination in healthy adults supported previous findings of PFAS immunosuppression in larger cohorts. Furthermore, the results suggested that cellular mechanisms right after antigen exposure should be investigated more closely to identify possible mechanisms of immunosuppression from PFAS.

Safety and immunogenicity of a parenterally administered rotavirus VP8 subunit vaccine in healthy adults

BackgroundThe P2-VP8 subunit vaccine for the prevention of rotavirus gastroenteritis is comprised of a truncated VP8 subunit protein from the rotavirus Wa strain (G1[P8]) fused to the tetanus toxin P2 epitope, and adsorbed on aluminum hydroxide for intramuscular administration. MethodsThree groups of 16 adults were randomized to receive three injections of P2-VP8 (12) or placebo (4) at doses of 10, 30 or 60μg of vaccine. IgG and IgA antibodies to P2-VP8 were assessed by ELISA in serum and lymphocyte supernatant (ALS). Serum samples were tested for neutralizing antibodies to homologous and heterologous strains of rotavirus. ResultsThe vaccine was well-tolerated. All vaccine recipients demonstrated significant IgA responses and all but one demonstrated IgG responses; in the 60μg cohort, geometric mean titers (GMTs) rose 70- and 80-fold for IgA and IgG, respectively. Homologous neutralizing antibody responses were observed in about half of participants in all three dose cohorts; in the 60μg cohort, GMTs against Wa rose from 128 to 992. Neutralizing antibody responses were robust to P[8] strains, moderate to P[4] strains and negligible to P[6] strains. ALS IgA responses were dose dependent. ConclusionsThe P2-VP8 subunit vaccine was well tolerated and evoked promising immune responses. Clinical trials registrationNCT01764256

Characterization of an age-response relationship to GSK's recombinant hepatitis B vaccine in healthy adults: An integrated analysis

The immune system becomes less effective with age, and older age is associated with an increased susceptibility to diseases and reduced responses to vaccination. Furthermore, some adult populations, such as those with diabetes mellitus, are at increased risk of acute hepatitis B virus (HBV) infection. Decreasing responses to vaccination with advanced age have been described, but it is not known at what age immunogenicity starts to reduce, or until what age immunogenicity remains acceptable (for example ≥80 % seroprotection post-vaccination). We characterized the relationship between age and seroprotection rate induced by recombinant HBV vaccination by conducting a pooled analysis of clinical trial data. Healthy adults aged ≥20 y who had been vaccinated with 20μg HBV vaccine (Engerix™ B, GSK Vaccines, Belgium) in a 0, 1, 6 months schedule in 11 studies since 1996 were included. The observed seroprotection rate, defined as an anti-HBV surface antigen antibody concentration ≥10 mIU/ml was 94.5% in the whole population (N = 2,620, Total vaccinated cohort), ranging from 98.6% in adults vaccinated at age 20–24 years, to 64.8% in those vaccinated at age ≥65 y A model on seroprotection rates showed a statistically significant decrease with age, and predicted that the anti-HBs seroprotection rate remains ≥90% up to 49 y of age and ≥80% up to 60 y of age. Individuals at risk of HBV infection should be vaccinated as early in life as possible to improve the likelihood of achieving seroprotection. Additional studies are needed to identify whether unvaccinated individuals older than 60 y would benefit from regimens that include additional or higher vaccine doses.

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.