Prevention of tick-borne encephalitis by FSME-IMMUN vaccines: review of a clinical development programme

The need for highly effective tick-borne encephalitis (TBE) vaccines has increased globally due to a variety of factors including climate, social, economic and demographic changes, which are thought to have promoted the expansion of the endemic region of TBE viruses. The first TBE vaccine, FSME-IMMUN^® Inject, was introduced in the 1970s and has been continually improved since then to enhance both its safety and immunogenicity. The current formulation was established in 2001 and is marketed as FSME-IMMUN^®. This review summarizes findings of the clinical development programme since 2001 regarding determination of the optimal dose, conventional and rapid vaccination schedules, vaccination in adults, the elderly and special patient populations, safety, immunogenicity, and immunopersistence in adults and children, comparison of FSME-IMMUN^® with another commercially available TBE vaccine as well as post-marketing vaccination outcome. This successful research programme demonstrated the strong immunogenicity and continued safety of the FSME-IMMUN^® vaccine, which is further confirmed by the performance reported under field conditions.     

Comparison of immunogenicity and safety between two paediatric TBE vaccines

TBE vaccination strategies capable of inducing strong paediatric immunogenicity and acceptable reactogenicity are still under evaluation. This single-blind, multi-center, randomized, controlled, phase III clinical study compared the immunogenicity and safety of the two paediatric TBE vaccines available in Europe (FSME-IMMUN^® Junior and Encepur^® Children) following administration of two doses of either vaccine in 303 children aged 1–11 years. Regardless of immunological test or viral antigen used, immunological responses were consistently higher in children vaccinated with FSME-IMMUN^® Junior than those vaccinated with Encepur^® Children. FSME-IMMUN^® Junior is also non-inferior to Encepur^® Children, with respect to NT seropositivity rates (p < 0.0001). Systemic reaction rates were low and similar between the vaccines. However, among children aged 7–11 years, local reactions were significantly higher after the first (p < 0.01) and second (p < 0.001) vaccination with Encepur^® Children than with FSME-IMMUN^® Junior, affecting half the children in the former group: 22.4% and 10.2% with FSME-IMMUN^® Junior vs. 49.0% and 51.0% for Encepur^® Children.     

Anthrax vaccine adsorbed: Further evidence supporting continuing the vaccination series rather than restarting the series when doses are delayed

Whether to restart or continue the series when anthrax vaccine doses are missed is a frequent medical management problem. We applied the noninferiority analysis model to this prospective study comparing the Bacillus anthracis protective antigen (PA) IgG antibody response and lethal toxin neutralization activity at day 28 to the anthrax vaccine adsorbed (AVA) (Biothrax^®) administered on schedule or delayed. A total of 600 volunteers were enrolled: 354 in the on-schedule cohort; 246 in the delayed cohort. Differences were noted in immune responses between cohorts (p < 0.0001) and among the racial categories (p < 0.0001). Controlling for covariates, the delayed cohort was non-inferior to the on-schedule cohort for the rate of 4-fold rise in both anti-PA IgG concentration (p < 0.0001) and TNA ED₅₀ titers (p < 0.0001); as well as the mean log₁₀-transformed anti-PA IgG concentration (p < 0.0001) and the mean log₁₀-transformed TNA ED₅₀ titers (p < 0.0001). Providing a missed AVA dose after a delay as long as 5–7 years, elicits anti-PA IgG antibody and TNA ED₅₀ responses that are robust and non-inferior to the responses observed when the 6-month dose is given on-schedule. These important data suggest it is not necessary to restart the series when doses of the anthrax vaccine are delayed as long as 5 or more years.     

MF59-adjuvanted influenza vaccine (FLUAD) in children: Safety and immunogenicity following a second year seasonal vaccination

After priming with two intramuscular doses of MF59^®-adjuvanted (Sub/MF59) or split influenza vaccines during the 2006/07 season, 89 healthy children received a third booster dose of the respective vaccine (2007/08 Northern Hemisphere formulation) approximately 1 year later, and were followed up for 6 months post-third injection. Immunogenicity was evaluated on 81 of them by a hemagglutination inhibition (HI) assay before and 3 weeks after vaccination.     

A Vaxfectin-adjuvanted HSV-2 plasmid DNA vaccine is effective for prophylactic and therapeutic use in the guinea pig model of genital herpes

Here we describe studies in the guinea pig model of genital herpes to evaluate a novel plasmid DNA (pDNA) vaccine encoding the HSV-2 glycoprotein D and UL46 and UL47 genes encoding tegument proteins VP11/12 and VP 13/14 (gD2/UL46/UL47), formulated with a cationic lipid-based adjuvant Vaxfectin^®. Prophylactic immunization with Vaxfectin^®-gD2/UL46/UL47 significantly reduced viral replication in the genital tract, provided complete protection against both primary and recurrent genital skin disease following intravaginal HSV-2 challenge, and significantly reduced latent HSV-2 DNA in the dorsal root ganglia compared to controls. We also examined the impact of therapeutic immunization of HSV-2 infected animals. Here, Vaxfectin^®-gD2/UL46/UL47 immunization significantly reduced both the frequency of recurrent disease and viral shedding into the genital tract compared to controls. This novel adjuvanted pDNA vaccine has demonstrated both prophylactic and therapeutic efficacy in the guinea pig model of genital herpes and warrants further development.     

Eleven years of Inflexal V—a virosomal adjuvanted influenza vaccine

Since the introduction to the Swiss market in 1997, Crucell (former Berna Biotech Ltd.), has sold over 41 million doses worldwide of the virosomal adjuvanted influenza vaccine, Inflexal^® V. Since 1992, 29 company sponsored clinical studies investigating the efficacy and safety of Inflexal^® V have been completed in which 3920 subjects participated. During its decade on the market, Inflexal^® V has shown an excellent tolerability profile due to its biocompatibility and purity. The vaccine contains no thiomersal or formaldehyde and its purity is reflected in the low ovalbumin content. By mimicking natural infection, the vaccine is highly efficacious. Inflexal^® V is the only adjuvanted influenza vaccine licensed for all age groups and shows a good immunogenicity in both healthy and immunocompromised elderly, adults and children. This review presents and discusses the experience with Inflexal^® V during the past decade.     

Immunogenicity and safety of IXIARO (IC51) in a Phase II study in healthy Indian children between 1 and 3 years of age

For adults the standard administration of the Japanese encephalitis vaccine IXIARO^® is two injections of 6 μg in a 28-day interval. Immunogenicity and safety of 3 and 6 μg of IXIARO^® compared to JenceVac™ were investigated in 60 healthy Indian children aged between 1 and 3 years. JE specific neutralizing antibodies were measured at baseline and 28 days after the first and second vaccination. On Day 56 SCR of the 3 and 6 μg IXIARO^® and the JenceVac™ group were 95.7%, 95.2% and 90.9%, respectively, and GMT were 201, 218 and 230, respectively, both without statistically significant difference between the three groups. Local and systemic tolerability were captured in a diary 7 days post-vaccination. No apparent difference was seen in the safety profile between the vaccines. These first immunogenicity and safety data in children are promising and support the use of a 3 μg dose in children below the age of three for further development of IXIARO^® in the paediatric population.     

A new oral vaccine candidate based on the microencapsulation by spray-drying of inactivated Vibrio cholerae

The aim of this work was to evaluate the microencapsulation by spray-drying of inactivated Vibrio cholerae, using methacrylic copolymers Eudragit^® L30D-55 and FS30D. The microparticles obtained presented a particle size around 3.0 μm. The preparation temperature affected the morphology and the antigenicity of microparticles, but it did not affect the V. cholerae content. In vitro release studies showed that in acid medium less than 5% of bacteria was released, and in neutral medium, Eudragit^® L30D-55 microparticles released 86% after 24 h, whereas FS30D released less than 30%. Rats inoculated with microparticles exhibited vibriocidal antibody titres. Microencapsulation by spray-drying of inactivated V. cholerae could be proposed as a method to obtain an oral vaccine which provides controlled release of the bacteria.     

Characterization of neutralizing antibodies to Far Eastern of tick-borne encephalitis virus subtype and the antibody avidity for four tick-borne encephalitis vaccines in human

We assessed the humoral immunity of 290 vaccinated persons against tick-borne encephalitis (TBE). During the first year and 2 years after the primary three vaccinations the antibodies to the Far Eastern subtype tick-borne encephalitis virus strain P-73 were detected by neutralization test after immunization with FSME-Immune Inject vaccine (Baxter Vaccine AG, Austria) in 88.2% and 78.1% vaccinated persons, respectively; with Encepur^® Adult vaccine (Novartis Vaccines, Germany), in 100% and 100%; with the vaccine of the Chumakov Institute of Poliomyelitis and Viral Encephalitides RAMSci (Russia), in 100% and 94.1%; with EnceVir vaccine (Russia), in 88.2% and 83.9%; and after combined vaccination, in 100% and 92.7%. The dynamics of the decrease in IgG avidity index correlated with the changes of antibody titers determined by neutralization test. After the primary vaccination course, the titers of virus-neutralizing antibodies were high (6.3–7.4 log₂) when the avidity index of IgG antibodies were 31% and more; thus, this level can be considered immunologically significant. Two years after the primary vaccination course, the IgG avidity indexes of 60% and more can be regarded as significant on the background of the GMT decrease of virus-neutralizing antibodies. These results allow us to recommend all four vaccines for mass vaccination and an assay of IgG avidity, along with neutralization test, for a more adequate assessment of the level of postvaccination immune response.     

Clinical evaluation of a polygeline-free tick-borne encephalitis vaccine for adolescents and adults

OBJECTIVE: To evaluate immunogenicity and safety of a polygeline-free tick-born encephalitis (TBE) vaccine in a clinical program. METHOD: A total of 3118 subjects aged 12-76 years were enrolled in three clinical trials. The clinical studies were conducted in 15 centers in three European countries. Evidence of neutralizing TBE antibodies was used as surrogate parameter for efficacy assessment. RESULTS: All subjects analyzed achieved levels of TBE antibodies postimmunization to fulfill the definition of seroconversion or a four-fold increase. The new TBE vaccine appeared to be well tolerated by subjects. Only very few febrile reactions, mainly 38.5 degrees C were reported. No serious or unexpected adverse events related to vaccination were reported. CONCLUSION: These successful results in terms of both immunogenicity and safety indicate that the TBE vaccination with this polygeline-free TBE vaccine can be used safely in adolescents and adults.     

Evaluation of the efficacy of modified vaccinia Ankara (MVA)/IMVAMUNE against aerosolized rabbitpox virus in a rabbit model

Infection of rabbits with aerosolized rabbitpox virus (RPXV) produces a disease similar to monkeypox and smallpox in humans and provides a valuable, informative model system to test medical countermeasures against orthopoxviruses. Due to the eradication of smallpox, the evaluation of the efficacy of new-generation smallpox vaccines depends on relevant well-developed animal studies for vaccine licensure. In this study, we tested the efficacy of IMVAMUNE^® [modified vaccinia Ankara-Bavarian Nordic (MVA-BN^®)] for protecting rabbits against aerosolized RPXV. Rabbits were vaccinated with either phosphate-buffered saline (PBS), Dryvax^®, a single low dose of IMVAMUNE^®, a single high dose of IMVAMUNE^®, or twice with a high dose of IMVAMUNE^®. Aerosol challenge with a lethal dose of RPXV was performed 4 weeks after the last vaccination. All PBS control animals succumbed to the disease or were euthanized because of the disease within 7 days postexposure. The rabbits vaccinated with Dryvax^®, a low dose of IMVAMUNE^®, or a single high dose of IMVAMUNE^® showed minimal to moderate clinical signs of the disease, but all survived the challenge. The only clinical sign displayed by rabbits that had been vaccinated twice with a high dose of IMVAMUNE^® was mild transient anorexia in just two out of eight rabbits. This study shows that IMVAMUNE^® can be a very effective vaccine against aerosolized RPXV.     

Effect of delayed anthrax vaccine dose on Bacillus anthracis protective antigen IgG response and lethal toxin neutralization activity

We describe the Bacillus anthracis protective antigen IgG antibody response and the B. anthracis lethal toxin neutralization activity to a delayed dose of anthrax vaccine adsorbed (AVA, BioThrax^®) using validated assays. 373 individuals received 1, 2, or 3 priming doses, 18–24 months afterward, they received a delayed dose of AVA. Overall, 23.6% of subjects showed detectable anti-PA IgG before the boost, compared to 99.2% (P < 0.0001) 28 days after the boost. Geometric mean anti-PA IgG concentration (GMC) was 1.66 μg/mL before and 887.82 μg/mL after the boost (P < 0.0001). The proportion of individuals with four-fold increase in GMC following the boost ranged from 93.8% to 100%. Robust anti-PA IgG levels and B. anthracis lethal toxin neutralization activity are induced when an AVA dose is delayed as long as two years. These data support continuing with the vaccination schedule when a dose is delayed as long as two years rather than restarting the series.     

Technology transfer and scale-up of the Flublok recombinant hemagglutinin (HA) influenza vaccine manufacturing process

Multiple different hemagglutinin (HA) protein antigens have been reproducibly manufactured at the 650 L scale by Protein Sciences Corporation (PSC) based on an insect cell culture with baculovirus infection. Significantly, these HA protein antigens were produced by the same Universal Manufacturing process as described in the biological license application (BLA) for the first recombinant influenza vaccine approved by the FDA (Flublok^®). The technology is uniquely designed so that a change in vaccine composition can be readily accommodated from one HA protein antigen to another one. Here we present a vaccine candidate to combat the recently emerged H7N9 virus as an example starting with the genetic sequence for the required HA, creation of the baculovirus and ending with purified protein antigen (or vaccine component) at the 10 L scale accomplished within 38 days under GMP conditions.     

Double-blind,randomized, placebo-controlled Phase I Clinical Trial of the therapeutical antituberculous vaccine RUTI

A Phase I interventional Clinical Trial was performed with a potential tuberculosis vaccine, based on detoxified cellular fragments of M. tuberculosis, named RUTI^®. The objective was to evaluate the safety profile and T-cell immune responses over a 6-month period following subcutaneous inoculation. The double-blind, randomized and placebo-controlled trial was conducted in healthy volunteers, all recruited at one site. RUTI^®, at each of the four tested doses, starting from 5 μg and going up to 200 μg, and placebo were inoculated to groups of 4 and 2 volunteers respectively, consecutively. RUTI^® appeared to be well tolerated as judged by local and systemic clinical evaluation, though vaccine dose dependent local adverse reactions were recorded. T-cell responses of blood lymphocytes to PPD and a number of antigen subunits were elevated, when compared with controls subjects. These results support the feasibility of future evaluation, to be targeted at subjects with latent tuberculosis infection (LTBI).     

Factors associated with herpes zoster vaccination status and acceptance of vaccine recommendation in community pharmacies

Objectives

1. Identify patient characteristics, awareness and knowledge associated with herpes zoster (HZ) vaccination status. 2. Identify self-reported reasons for not receiving Zostavax^®. 3. Assess the impact of a patient education program by measuring post-intervention interest in obtaining the Zostavax^® vaccine across reasons for being unvaccinated.

Methods

A cross-sectional design with patients aged 60 years or older in 51 community pharmacies in Alabama and Florida was utilized. During the Introductory Pharmacy Practice Experience in summer 2013, 137 immunization-certified student pharmacists provided patient education on HZ and Zostavax^® to unvaccinated patients using the Shingles Vaccine Information Statement. An interviewer-administered questionnaire assessed patient awareness of HZ, receipt of recommendations to receive Zostavax^®, and patient characteristics as well as vaccination status, reasons for being unvaccinated and interest in obtaining Zostavax^® after the educational session.

Results

A total of 681 patients participated in a conversation with a student pharmacist regarding their HZ vaccination status. The majority were female (57.6%), white (84.6%), and unvaccinated (73.6%). Results from logistic regression suggest that participants were more likely to be vaccinated if they received a recommendation from a healthcare provider (OR = 5.15), received the influenza vaccine during the previous year (OR = 3.56), or knew that Zostavax^® was recommended for individuals over 60 years of age (OR = 3.55). The most frequently provided reasons for being unvaccinated were “haven’t gotten around to it/forgot” (27.2%) and “didn’t know it was needed” (27.1%). After the educational session, the majority (72.5%) of unvaccinated patients were interested in speaking with their pharmacist or physician about receiving Zostavax^®. Analysis suggests that interest differed across initial reason for being unvaccinated (χ² = 64.44; p < 0.01).

Implications/conclusions

Recommendations from healthcare providers are valued by patients and can improve vaccination rates. The patient education program increased interest in receiving Zostavax^® and this interest differed depending on the reason provided for being unvaccinated.     

Are the defined substrate-based methods adequate to determine the microbiological quality of natural recreational waters?

Monitoring the microbiological quality of water used for recreational activities is very important to human public health. Although the sanitary quality of recreational marine waters could be evaluated by standard methods, they are time-consuming and need confirmation. For these reasons, faster and more sensitive methods, such as the defined substrate-based technology, have been developed. In the present work, we have compared the standard method of membrane filtration using Tergitol-TTC agar for total coliforms and Escherichia coli, and Slanetz and Bartley agar for enterococci, and the IDEXX defined substrate technology for these faecal pollution indicators to determine the microbiological quality of natural recreational waters. ISO 17994:2004 standard was used to compare these methods. The IDEXX for total coliforms and E. coli, Colilert^®, showed higher values than those obtained by the standard method. Enterolert^® test, for the enumeration of enterococci, showed lower values when compared with the standard method. It may be concluded that more studies to evaluate the precision and accuracy of the rapid tests are required in order to apply them for routine monitoring of marine and freshwater recreational bathing areas. The main advantages of these methods are that they are more specific, feasible and simpler than the standard methodology.     

Prenatal vitamin A deficiency impairs adaptive immune responses to pentavalent rotavirus vaccine (RotaTeq) in a neonatal gnotobiotic pig model

Vitamin A deficiency (VAD) is associated with increased childhood mortality and morbidity in impoverished Asian and African countries, but the impact of VAD on rotavirus (RV) vaccine or infection is poorly understood. We assessed effects of gestational and dietary induced pre- and post-natal VAD and vitamin A supplementation on immune responses to a pentavalent rotavirus vaccine, RotaTeq^® in a neonatal gnotobiotic pig model. Vaccine efficacy was assessed against virulent G1P[8] human rotavirus (HRV) challenge. VAD and vitamin A sufficient (VAS) piglets were derived from dietary VAD and VAS sows, respectively. VAD piglets had significantly lower levels of hepatic vitamin A compared to that of VAS piglets. RotaTeq^®-vaccinated VAD piglets had 350-fold higher fecal virus shedding titers compared to vaccinated VAS piglets post-challenge. Only 25% of vaccinated non-vitamin A supplemented VAD piglets were protected against diarrhea compared with 100% protection rate in vaccinated non-supplemented VAS piglets post-challenge. Intestinal HRV specific immune responses were compromised in VAD piglets. Vaccinated VAD piglets had significantly lower ileal HRV IgG antibody secreting cell (ASC) responses (pre-challenge) and duodenal HRV IgA ASC responses (post-challenge) compared to vaccinated VAS piglets. Also, intestinal HRV IgA antibody titers were 11-fold lower in vaccinated VAD compared to vaccinated VAS piglets post-challenge. Persistently elevated levels of IL-8, a pro-inflammatory mediator, and lower IL-10 responses (anti-inflammatory) in vaccinated VAD compared to VAS piglets suggest more severe inflammatory responses in VAD piglets post-challenge. Moreover higher IFN-γ responses pre-challenge were observed in VAD compared to VAS piglets. The impaired vaccine-specific intestinal antibody responses and decreased immunoregulatory cytokine responses coincided with reduced protective efficacy of the RV vaccine against virulent HRV challenge in VAD piglets. In conclusion, VAD impaired antibody responses to RotaTeq^® and vaccine efficacy. Oral supplementation of 100,000 IU vitamin A concurrent with RV vaccine failed to increase the vaccine efficacy in VAD piglets.     

Ischemic cardiac events and other adverse events following ACAM2000 smallpox vaccine in the Vaccine Adverse Event Reporting System

Background

The Vaccine Adverse Event Reporting System (VAERS) is a passive reporting system, used for monitoring the safety of all US licensed vaccines. In March 2008, ACAM2000^® replaced Dryvax^® as the only licensed smallpox vaccine and is administered to all persons entering military service and certain civilian researchers. In 2011, routine data mining of VAERS identified a vaccine safety concern resulting in acute ischemic cardiac events (ICE) following ACAM2000^®.

Methods

During March 1, 2008 through June 30, 2013, we reviewed all serious reports received following ACAM2000^®and classified them by diagnostic category. We identified possible ICE cases by searching the Medical Dictionary for Regulatory Affairs (MedDRA^®) terms for “myocardial ischaemia,” “acute myocardial infarction,” “myocardial infarction,” and “ischaemia,” and applied standardized surveillance case definitions.

Results

VAERS received 1149 reports following ACAM2000^® administration; 169 (14.7%) were serious (resulting in permanent disability, hospitalization or prolongation of hospitalization, life-threatening illness or death), including one death. The two most frequent diagnostic categories for serious reports were cardiovascular and other infectious conditions. The MedDRA^® search found 31 reports of possible ICE after receipt of ACAM2000^® vaccine. Of a total 30 possible ICE cases with demographic information, all but one was male; the age range was 20–45 years (median 32) and median interval to onset of symptoms was 12 days. On clinical review there were 16 cases of myocarditis/pericarditis and 15 ICE cases.

Conclusions

Our review of the data mining signal did not substantiate the concerns about ICE after ACAM2000^®. Our study also suggests that with current pre-vaccination screening, cardiac morbidity in generally healthy vaccinated populations remains uncommon.     

Enhanced and persistent antibody response against homologous and heterologous strains elicited by a MF59®-adjuvanted influenza vaccine in infants and young children

Background

Non-adjuvanted seasonal influenza vaccines show only modest efficacy in young children. This study compared the immunogenicity, reactogenicity and safety of the MF59^®-adjuvanted trivalent subunit vaccine (aTIV) with two non-adjuvanted trivalent vaccines, TIV-1, the non-adjuvanted version of aTIV, and TIV-2, a split virion vaccine.

Methods

6078 children received two doses of aTIV (n = 3125), TIV-1 (n = 1479), or TIV-2 (n = 1474) four weeks apart (Days 1 and 29). Children aged 6 to <36 months and 36 to <72 months received 0.25 mL and 0.50 mL doses, respectively. Immunogenicity was assessed by hemagglutination inhibition (HI) assay (n = 2435) on Days 1, 29, 50 and 209. Safety was assessed up to Day 394.

Results

After the second vaccination (Day 50), the aTIV group showed significantly higher geometric mean HI titers and seroconversion rates than the TIV-1 or TIV-2 groups against all homologous and heterologous strains. The difference was enhanced at HI titers ≥110. aTIV elicited a faster, more persistent antibody response, with significantly higher titers in the aTIV group after one vaccination (Day 29) and after six months (Day 209) than in either TIV group. aTIV was more reactogenic than were TIV-1 and TIV-2 but rates of severe adverse events were very low for all three vaccines.

Conclusion

In infants and young children, the MF59-adjuvanted vaccine induced substantially faster (after one dose), higher, persistent HI titers than the non-adjuvanted vaccines, with consistently higher seroprotection rates at increased threshold HI titers.This trial is registered at clinicaltrials.gov: NCT01346592.