Acceptance of Intanza® 9 μg intradermal influenza vaccine in routine clinical practice in Australia and Argentina

Microneedles enable the development of skin-targeted vaccines against coronaviruses and influenza viruses

Throughout the COVID-19 pandemic, many have seriously worried that the plus burden of seasonal influenza that might create a destructive scenario, resulting in overwhelmed healthcare capacities and onwards loss of life. Many efforts to develop a safe and efficacious vaccine to prevent infection by coronavirus and influenza, highlight the importance of vaccination to combat infectious pathogens. While vaccines are traditionally given as injections into the muscle, microneedle (MN) patches designed to precisely deliver cargos into the cutaneous microenvironment, rich in immune cells, provide a noninvasive and self-applicable vaccination approach, reducing overall costs and improving access to vaccines in places with limited supply. The current review aimed to highlight advances in research on the development of MNs-mediated cutaneous vaccine delivery. Concluding remarks and challenges on MNs-based skin immunization are also provided to contribute to the rational development of safe and effective MN-delivered vaccines against these emerging infectious diseases.

Immunogenicity and Safety of Reduced-Dose Intradermal vs Intramuscular Influenza Vaccines: A Systematic Review and Meta-analysis

IMPORTANCE

Low-dose intradermal influenza vaccines could be a suitable alternative to full intramuscular dose during vaccine shortages.

OBJECTIVE

To compare the immunogenicity and safety of the influenza vaccine at reduced or full intradermal doses with full intramuscular doses to inform policy design in the event of vaccine shortages.

DATA SOURCES

MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials were searched for studies published from 2010 until June 5, 2020.

STUDY SELECTION

All comparative studies across all ages assessing the immunogenicity or safety of intradermal and intramuscular influenza vaccinations were included.

DATA EXTRACTION AND SYNTHESIS

Data were extracted by a single reviewer and verified by a second reviewer. Discrepancies between reviewers were resolved through consensus. Random-effects meta-analysis was conducted.

MAIN OUTCOMES AND MEASURES

Primary outcomes included geometric mean titer, seroconversion, seroprotection, and adverse events.

RESULTS

A total of 30 relevant studies were included; 29 studies were randomized clinical trials with 13 759 total participants, and 1 study was a cohort study of 164 021 participants. There was no statistically significant difference in seroconversion rates between the 3-µg, 6-µg, 7.5-µg, and 9-µg intradermal vaccine doses and the 15-µg intramuscular vaccine dose for each of the H1N1, H3N2, and B strains, but rates were significantly higher with the 15-µg intradermal dose compared with the 15-µg intramuscular dose for the H1N1 strain (rate ratio [RR], 1.10; 95% CI, 1.01-1.20) and B strain (RR, 1.40; 95% CI, 1.13-1.73). Seroprotection rates for the 9-µg and 15-µg intradermal doses did not vary significantly compared with the 15-µg intramuscular dose for all the 3 strains, except for the 15-µg intradermal dose for the H1N1 strain, for which rates were significantly higher (RR, 1.05; 95% CI, 1.01-1.09). Local adverse events were significantly higher with intradermal doses than with the 15-µg intramuscular dose, particularly erythema (3-µg dose: RR, 9.62; 95% CI, 1.07-86.56; 6-µg dose: RR, 23.79; 95% CI, 14.42-39.23; 9-µg dose: RR, 4.56; 95% CI, 3.05-6.82; 15-µg dose: RR, 3.68; 95% CI, 3.19-4.25) and swelling (3-µg dose: RR, 20.16; 95% CI, 4.68-86.82; 9-µg dose: RR, 5.23; 95% CI, 3.58-7.62; 15-µg dose: RR, 3.47 ; 95% CI, 2.21-5.45). Fever and chills were significantly more common with the 9-µg intradermal dose than the 15-µg intramuscular dose (fever: RR, 1.36; 95% CI, 1.03-1.80; chills: RR, 1.24; 95% CI, 1.03-1.50) while all other systemic adverse events were not statistically significant for all other doses.

CONCLUSIONS AND RELEVANCE

These findings suggest that reduced-dose intradermal influenza vaccination could be a reasonable alternative to standard dose intramuscular vaccination.

Immunogenicity, safety and tolerability of intradermal influenza vaccines

Intradermal influenza vaccination has been studied for more than 80 y. The revived interest in this strategy of vaccination is a result of the innovative technologies in needle design allowing more precise injection and making the device easier to use. Furthermore, clinical trials on these novel devices have demonstrated significant dose sparing effects, improved immunogenicity and very few adverse effects. This review compares intradermal vaccination with various devices with subcutaneous and intramuscular vaccination. We also discussed the role of topical adjuvant before intradermal vaccination.

Human studies with microneedles for evaluation of their efficacy and safety

INTRODUCTION

During the past two decades, many studies have documented the development of microneedles (MNs) as a feasible technique for the effective administration of drugs. More and more human studies have been done with MNs to bridge the gap between research and market applications that provide efficacious techniques for clinical implementation.

AREAS COVERED

The aim of this review is provide a brief description of the status of human study with MNs and to demonstrate progress for the right use of microneedle arrays in clinical settings. It also describes the considerations for clinical application with each type of MNs.

EXPERT OPINION

Microneedle systems were introduced to overcome the limitations of conventional methods of drug administration. Lots of microneedle systems have undergone clinical evaluation to determine their efficacy and safety, and many studies have demonstrated positive results. The successful clinical use of the microneedle in vaccine therapy is remarkable and supports the importance of conducting further tests in a wide range of medical applications. Self-administered MNs appeared to be an attractive alternative method that needs further research to become a reality in the near future.

Fluzone® Intradermal Quadrivalent Influenza Vaccine

INTRODUCTION

An intradermal version of Fluzone® split-virion inactivated trivalent influenza vaccine, containing 9 µg hemagglutinin per strain of A/H1N1, A/H3N2, and one B lineage virus (Fluzone Intradermal, Sanofi Pasteur), became available in the US during the 2011-2012 influenza season for adults 18-64 years of age. In advance of the 2015-2016 season, Fluzone Intradermal was replaced with Fluzone Intradermal Quadrivalent vaccine, which contains 9 µg hemagglutinin per strain of the two A-strain viruses and both B-strain lineage viruses (Victoria and Yamagata).

AREAS COVERED

This literature review summarizes the history and mechanism of intradermal vaccination, discusses the clinical trial results supporting the immunogenicity and safety of Fluzone Intradermal Quadrivalent vaccine, and describes the unique microinjection system used to deliver Fluzone Intradermal Quadrivalent. Expert commentary: Fluzone Intradermal Quadrivalent may boost confidence in influenza vaccination with the addition of a second B-lineage strain. By using an innovative microinjection system, the vaccine is also designed to address some of the logistic challenges faced by healthcare providers administering immunizations.

Fluzone® intra-dermal (Intanza®/Istivac® Intra-dermal): An updated overview

Influenza is a highly contagious respiratory acute viral disease which imposes a very heavy burden both in terms of epidemiology and costs, in the developed countries as well as in the developing ones. It represents a serious public health concern and vaccination constitutes an important tool to reduce or at least mitigate its burden. Despite the existence of a broad armamentarium against influenza and despite all the efforts and recommendations of international organisms to broaden immunization, influenza vaccination coverage is still far from being optimal. This, taken together with logistic and technical difficulties that can result into vaccine shortage, makes intra-dermal (ID) vaccines, such as Fluzone® ID and Intanza®, particularly attractive. ID vaccines are comparable and, in some cases, superior to intra-muscular/sub-cutaneous vaccines in terms of immunogenicity, safety, reactogenicity, tolerability and cross-protection profiles, as well as in terms of patient preference, acceptance and vaccine selection. Further advances, such as Fluzone® ID with alternative B strains and Quadrivalent Fluzone® ID or the possibility of self-administering the vaccines, make influenza ID vaccines even more valuable.

Intradermal vaccination for infants and children

Intradermal (ID) vaccination induces a more potent immune response and requires lower vaccine doses as compared with standard vaccination routes. To deliver ID vaccines effectively and consistently, an ID delivery device has been developed and is commercially available for adults. The clinical application of ID vaccines for infants and children is much anticipated because children receive several vaccines, on multiple occasions, during infancy and childhood. However, experience with ID vaccines is limited and present evidence is sparse and inconsistent. ID delivery devices are not currently available for infants and children, but recent studies have examined skin thickness in this population and reported that it did not differ in proportion to body size in infants, children, and adults. These results are helpful in developing new ID devices and for preparing new vaccines in infants and children.

Acceptance of intradermal inactivated influenza vaccines among hospital staff following 2 seasonal vaccination campaigns

After a Canadian hospital's official influenza vaccination campaign concluded in the 2011-2012 and 2012-2013 influenza seasons, study nurses provided additional vaccination mobile cart hours and the added choice of an intradermal injection. An additional 2.1% of staff in the first and 1.4% in the second season were vaccinated during the study with 90-99% preferring the intradermal injection or having no preference. All 13 staff who attempted self-injection with the intradermal vaccine in 2012-2013 were successful on their first attempt. Offering alternatives to intramuscular vaccines may increase rates of vaccination.

Intradermal vaccination using the novel microneedle device MicronJet600: Past, present, and future

Intradermal immunization has become a forefront of vaccine improvement, both scientifically and commercially. Newer technologies are being developed to address the need to reduce the dose required for vaccination and to improve the reliability and ease of injection, which have been major hurdles in expanding the number of approved vaccines using this route of administration. In this review, 7 y of clinical experience with a novel intradermal delivery device, the MicronJet600, which is a registered hollow microneedle that simplifies the delivery of liquid vaccines, are summarized. This device has demonstrated both significant dose-sparing and superior immunogenicity in various vaccine categories, as well as in diverse subject populations and age groups. These studies have shown that intradermal delivery using this device is safe, effective, and preferred by the subjects. Comparison with other intradermal devices and potential new applications for intradermal delivery that could be pursued in the future are also discussed.

Immunogenicity and safety of intradermal trivalent influenza vaccination in nursing home older adults: a randomized controlled trial

OBJECTIVE

To compare the immunogenicity and safety between full-dose (15 μg) intramuscular (i.m.) and full-dose (15 μg) intradermal (i.d.) immunization of the trivalent influenza vaccine in nursing home older adults.

DESIGN

A single-center, randomized, controlled, open-label, parallel group trial from October 2013 to April 2014.

SETTING

Nine nursing homes in Hong Kong.

PARTICIPANTS

Hundred nursing home older adults (mean age: 82.9 ± 7.4 years).

INTERVENTION

Fifty received i.d. (Intanza) and 50 received i.m. (Vaxigrip) vaccination.

MEASUREMENTS

Baseline measurements included demographics, comorbidity, frailty and nutritional status. Day 21 and day 180 immunogenicity (seroconversion rate, seroprotection rate, geometric mean titer [GMT] fold increase in antibody titer) using hemagglutination-inhibition and adverse events were measured. Noninferiority and superiority of i.d. compared with i.m. vaccination in immunogenicity were analyzed. The study was registered on ClinicalTrials.gov; identifier: NCT 01967368.

RESULTS

At day 21, noninferiority in immunogenicity of the i.d. vaccination was demonstrated. The seroconversion rate of the H1N1 strain was significantly higher in the i.d. group. At day 180, immunogenicity of both groups fell but the GMT of all strains in i.d. group was higher and the difference was significant for H3N2 strain. The seroconversion rate and GMT fold increase of H3N2 strain was significantly higher in the i.d. group. Local adverse events was significantly more in i.d. group, but they were mild and resolved in 72 hours.

CONCLUSIONS

I.d. vaccination is noninferior, and even superior in some parts of immunogenicity assessment, to i.m. vaccination without compromising safety in nursing home older adults. I.d. vaccination is a good alternative to i.m. vaccination in this population.

Adjuvanted influenza vaccines

Influenza is one of the most common causes of human morbidity and mortality that is preventable by vaccination. Immunization with available vaccines provides incomplete protection against illness caused by influenza virus, especially in high-risk groups such as the elderly and young children. Thus, more efficacious vaccines are needed for the entire population, and all the more so for high-risk groups. One way to improve immune responses and protection is to formulate the vaccine with antigen carriers and/or adjuvants, which can play an important role in improving immune responses and delivery to antigen-presenting cells, especially for a vaccine like influenza that is based on protein antigens usually administered without a carrier or adjuvant. In this review, the authors present an overview of available vaccines, focusing on research and development of new adjuvants used in influenza vaccines, as well as adjuvanted influenza vaccines aimed to improve immune responses, protection and breadth of coverage for influenza.

Microneedle patches: usability and acceptability for self-vaccination against influenza

While therapeutic drugs are routinely self-administered by patients, there is little precedent for self-vaccination. Convenient self-vaccination may expand vaccination coverage and reduce administration costs. Microneedle patches are in development for many vaccines, but no reports exist on usability or acceptability. We hypothesized that naïve patients could apply patches and that self-administered patches would improve stated intent to receive an influenza vaccine. We conducted a randomized, repeated measures study with 91 venue-recruited adults. To simulate vaccination, subjects received placebo microneedle patches given three times by self-administration and once by the investigator, as well as an intramuscular injection of saline. Seventy participants inserted patches with thumb pressure alone and the remainder used snap-based devices that closed shut at a certain force. Usability was assessed by skin staining and acceptability was measured with an adaptive-choice analysis. The best usability was seen with the snap device, with users inserting a median value of 93-96% of microneedles over three repetitions. When a self-administered microneedle patch was offered, intent to vaccinate increased from 44% to 65% (CI: 55-74%). The majority of those intending vaccination would prefer to self-vaccinate: 64% (CI: 51-75%). There were no serious adverse events associated with use of microneedle patches. The findings from this initial study indicate that microneedle patches for self-vaccination against influenza are usable and may lead to improved vaccination coverage.

Intralymphatic immunotherapy and vaccination in mice

Vaccines are typically injected subcutaneously or intramuscularly for stimulation of immune responses. The success of this requires efficient drainage of vaccine to lymph nodes where antigen presenting cells can interact with lymphocytes for generation of the wanted immune responses. The strength and the type of immune responses induced also depend on the density or frequency of interactions as well as the microenvironment, especially the content of cytokines. As only a minute fraction of peripherally injected vaccines reaches the lymph nodes, vaccinations of mice and humans were performed by direct injection of vaccine into inguinal lymph nodes, i.e. intralymphatic injection. In man, the procedure is guided by ultrasound. In mice, a small (5-10 mm) incision is made in the inguinal region of anesthetized animals, the lymph node is localized and immobilized with forceps, and a volume of 10-20 μl of the vaccine is injected under visual control. The incision is closed with a single stitch using surgical sutures. Mice were vaccinated with plasmid DNA, RNA, peptide, protein, particles, and bacteria as well as adjuvants, and strong improvement of immune responses against all type of vaccines was observed. The intralymphatic method of vaccination is especially appropriate in situations where conventional vaccination produces insufficient immunity or where the amount of available vaccine is limited.

Traditional and new influenza vaccines

The challenges in successful vaccination against influenza using conventional approaches lie in their variable efficacy in different age populations, the antigenic variability of the circulating virus, and the production and manufacturing limitations to ensure safe, timely, and adequate supply of vaccine. The conventional influenza vaccine platform is based on stimulating immunity against the major neutralizing antibody target, hemagglutinin (HA), by virus attenuation or inactivation. Improvements to this conventional system have focused primarily on improving production and immunogenicity. Cell culture, reverse genetics, and baculovirus expression technology allow for safe and scalable production, while adjuvants, dose variation, and alternate routes of delivery aim to improve vaccine immunogenicity. Fundamentally different approaches that are currently under development hope to signal new generations of influenza vaccines. Such approaches target nonvariable regions of antigenic proteins, with the idea of stimulating cross-protective antibodies and thus creating a "universal" influenza vaccine. While such approaches have obvious benefits, there are many hurdles yet to clear. Here, we discuss the process and challenges of the current influenza vaccine platform as well as new approaches that are being investigated based on the same antigenic target and newer technologies based on different antigenic targets.

Intanza (®) 9 µg intradermal seasonal influenza vaccine for adults 18 to 59 years of age

Seasonal influenza in healthy working-age adults accounts for a substantial part of the socioeconomic burden of this disease. Intanza® 9 µg (sanofi pasteur) is a microneedle-delivered intradermal trivalent inactivated influenza vaccine approved in 2009 for the prevention of seasonal influenza in adults 18 to 59 years of age. The microneedle system reliably and reproducibly delivers the vaccine to the dermis. Clinical studies show that Intanza 9 µg is as immunogenic and as well tolerated in working-age adults as a reference intramuscular trivalent inactivated vaccine. Local reactions to Intanza 9 µg, mainly erythema, are transient, mostly mild or moderate, and do not affect acceptability. Intanza 9 µg is considered satisfactory by at least 95% of both vaccinees and prescribers, especially because of the short needle and rapid administration. Because Intanza® 9 µg offers an alternative to intramuscular vaccines, it might help increase influenza vaccine coverage rates.

Intradermally-administered influenza virus vaccine is safe and immunogenic in healthy adults 18-64 years of age

BACKGROUND

To increase vaccine acceptance, intradermal (ID) influenza vaccine (Fluzone(®) Intradermal, Sanofi Pasteur Inc.) may be an attractive alternative to intramuscular (IM) vaccination due to smaller needle and volume injected.

METHODS

A multicenter, randomized (2:1 ID vs IM vaccines) study, blinded for ID vaccine lots, was conducted among 4292 adults 18-64 years of age enrolled in October 2008. Three lots of investigational trivalent influenza vaccine containing 9μg hemagglutinin (HA) per strain in 0.1mL administered ID with a 30 gauge, 1.5mm long needle were compared to standard dose vaccine (0.5mL containing 15μg HA/strain) given IM.

RESULTS

The post-vaccination antibody geometric mean titers (GMT) for the ID vaccine were similar to the IM vaccine (H1N1: 193.2 vs. 178.3, H3N2: 246.7 vs. 230.7, and B: 102.5 vs. 126.9). Non-inferiority was met for the ID vaccine compared to IM vaccine as assessed by antibody GMT ratios (IM/ID) for all three virus strains (H1N1: 0.92, H3N2: 0.94, and B: 1.24). Seroconversion rates were non-inferior for H1N1 and H3N2, but not for B (ID vs. IM: H1N1: 61.2% vs. 60.5%, H3N2: 75.3% vs. 74.8%, and B: 46.2% vs. 54.2%). Seroprotection (HAI titer ≥1:40) rates were similar between groups (ID vs. IM, H1N1: 91.1% vs. 91.7%, H3N2: 90.7% vs. 91.4%, and B: 87.4% vs. 89.3%). Local injection site reactions overall were more common with ID than IM vaccine (ID vs. IM: 89.2% vs. 60.2%), but were usually grade 1 or 2 and transient. The frequencies of local injection site pain and systemic reactions were similar between vaccine groups, except more myalgia with IM vaccine.

CONCLUSIONS

The ID vaccine elicited immune responses comparable to IM vaccine except for the seroconversion rate to B virus. With the exception of pain, local injection site reactions were more common with the ID vaccine, but well-tolerated and of short duration.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT00772109.

Head-to-head comparison of an intradermal and a virosome influenza vaccine in patients over the age of 60: evaluation of immunogenicity, cross-protection, safety and tolerability

In the present study we first compare immunogenicity against vaccine and heterologous circulating A(H1N1)pdm09 strains, tolerability and safety of intradermal Intanza 15 μg and of virosomal adjuvanted, intramuscularly delivered influenza vaccine, Inflexal V, in healthy elderly volunteers. Five-hundred participants were enrolled in the study and randomly assigned to the two vaccine groups to receive either one dose of Intanza 15 μg or Inflexal V vaccine. All subjects reported solicited local and systemic reactions occurred within 7 d after vaccination and unsolicited adverse events up to 21 d post-immunization and any serious adverse event appeared during the study. A subset of 55 participants was randomly selected for immunogenicity and cross-protection evaluations. Serum samples were collected before and 1 and 3 mo after immunization. Antibody responses were measured using hemagglutination inhibition (HI) against all viruses used in the study and neutralization (NT) assays against A(H1N1)pdm09 strains. At least one of the CHMP criteria for influenza vaccine approval in the elderly was met by virosomal vaccine against all the tested viruses; intradermal vaccine met all criteria against all strains. Several parameters of immune response against strains with a different antigenic pattern from that of vaccine A/California/04/09(H1N1)pdm09 were significantly higher in the intradermal vaccine group compared with the virosomal group. Safety and systemic tolerability of both vaccines were excellent, but injection site reactions occurred significantly more frequently in the intradermal vaccination group. Immunogenicity of Intanza 15 μg intradermal vaccine tended to be higher than that of Inflexal V against heterologous strains in healthy elderly.

Microneedle and mucosal delivery of influenza vaccines

In recent years with the threat of pandemic influenza and other public health needs, alternative vaccination methods other than intramuscular immunization have received great attention. The skin and mucosal surfaces are attractive sites probably because of both noninvasive access to the vaccine delivery and unique immunological responses. Intradermal vaccines using a microinjection system (BD Soluvia(TM)) and intranasal vaccines (FluMist®) are licensed. As a new vaccination method, solid microneedles have been developed using a simple device that may be suitable for self-administration. Because coated microneedle influenza vaccines are administered in the solid state, developing formulations maintaining the stability of influenza vaccines is an important issue to be considered. Marketable microneedle devices and clinical trials remain to be developed. Other alternative mucosal routes such as oral and intranasal delivery systems are also attractive for inducing cross-protective mucosal immunity, but effective non-live mucosal vaccines remain to be developed.

Attitudes of the general public and general practitioners in five countries towards pandemic and seasonal influenza vaccines during season 2009/2010

Background

Vaccination coverage rates for seasonal influenza are not meeting national and international targets. Here, we investigated whether the 2009/2010 A/H1N1 pandemic influenza affected the uptake of influenza vaccines.

Methodology/Principal Findings

In December 2009/January 2010 and April 2010, 500 randomly selected members of the general public in Germany, France, the United States, China, and Mexico were surveyed by telephone about vaccination for seasonal and A/H1N1 pandemic influenza. Also, in April 2010, 100 randomly selected general practitioners were surveyed. Adult vaccine coverage in December 2009/January 2010 for A/H1N1 pandemic and seasonal influenza were, respectively, 12% and 29% in France, 11% and 25% in Germany, 41% and 46% in the US, 13% and 30% in Mexico, and 12% and 10% in China. Adult uptake rates in April 2010 were higher in Mexico but similar or slightly lower in the other countries. Coverage rates in children were higher than in adults in the US, Mexico, and China but mostly lower in Germany and France. Germans and French viewed the threat of A/H1N1 pandemic influenza as low to moderate, whereas Mexicans, Americans, and Chinese viewed it as moderate to serious, opinions generally mirrored by general practitioners. The recommendation of a general practitioner was a common reason for receiving the pandemic vaccine, while not feeling at risk and concerns with vaccine safety and efficacy were common reasons for not being vaccinated. Inclusion of the A/H1N1 pandemic strain increased willingness to be vaccinated for seasonal influenza in the United States, Mexico, and China but not in Germany or France.

Conclusions/Significance

The 2009/2010 A/H1N1 influenza pandemic increased vaccine uptake rates for seasonal influenza in Mexico but had little effect in other countries. Accurate communication of health information, especially by general practitioners, is needed to improve vaccine coverage rates.

Dose sparing intradermal trivalent influenza (2010/2011) vaccination overcomes reduced immunogenicity of the 2009 H1N1 strain

BACKGROUND

We hypothesized that low dose intradermal vaccination of the trivalent influenza vaccine (TIV) delivered by the MicronJet600™ (NanoPass Technologies, Israel) would be non-inferior to the full dose intramuscular and mid dose Intanza(®) vaccination in the elderly and the chronically ill adults.

METHODS

We performed a prospective randomized trial on elderly and chronically ill adults. Subjects were randomly assigned into 4 groups. Groups ID3 and ID9 received reduced dose ID TIV (3 μg and 9 μg of hemagglutinin (HA) per strain respectively) delivered by MicronJet600™ (NanoPass Technologies, Israel). Group INT9 received reduced dose ID TIV (9 μg) delivered by Becton Dickinson's Soluvia™ device (Intanza(®)9, Sanofi-Pasteur, France). Control group IM15 received a full dose IM TIV (15 μg). We measured antibody titers by hemagglutination inhibition (HAI) and microneutralization (MN) assays at baseline and day 21.

RESULTS

Baseline characteristics for all groups were similar (group and sample sizes: ID3=63; ID9=68; INT9=65; and IM15=66). At day 21 post vaccination, the GMT ratio and the seroconversion rates difference for all three strains of the ID vaccine groups were non-inferior to the IM vaccine group. The seroconversion rate, seroprotection rate, and the GMT of the H1N1 strains by HAI and MN assays were significantly higher in the ID groups compared with the full dose IM vaccine group. The seroconversion rates of the H3N2 strain by HAI assay were also significantly higher in the ID groups when compared with the full dose IM group. Direct comparison among the three ID groups showed no significant differences. No serious adverse events related to vaccination were reported.

CONCLUSION

Dose-sparing ID TIV can overcome reduced immunogenicity of the H1N1 strain, and according to some measures, for the H3N2 strain. At risk subjects indicated for the TIV should be considered for intradermal immunization to compensate for reduced immunogenicity.

Phase 4 randomized trial of intradermal low-antigen-content inactivated influenza vaccine versus standard-dose intramuscular vaccine in HIV-1-infected adults

This study evaluated safety, tolerability and immunogenicity of intradermal (ID) trivalent inactivated split influenza vaccine, with a lower antigen content (9 mcg HA per strain) than the conventional intramuscular one (15 mcg), in HIV-1-infected adults younger than 60 years. A total of 54 HIV-1-positive participants were enrolled and randomly assigned to receive a single dose of either ID-administered low-antigen-content split inactivated vaccine or intramuscularly-administered (IM) standard-dose inactivated split vaccine. Subjects were provided with a diary to monitor any local and/or systemic reactions to the vaccine for 7 days following vaccination. Serum samples were collected before, 28 days and 90 days after immunization. The plasma HIV-RNA and CD4+ T-lymphocyte count were checked at day 0 and day 90. Serum hemagglutination-inhibition (HI) activity for the three influenza strains included in the vaccine composition was measured to assess the antibody response at one month and 3 months after vaccination. Both vaccines showed optimal safety and tolerability profiles. All the three Committee for Medicinal Products for Human Use immunogenicity criteria for vaccine approval in adults younger than 60 were met by both vaccines against A(H1N1) and A(H3N2) viruses. Both vaccines met mean-fold-increase and seroprotection criteria but failed seroconversion criteria against B virus. No difference in terms of post-vaccination geometric mean titers, mean fold increase, seroprotection and seroconversion rates were found comparing ID and IM vaccines. In conclusion, the recently available low-antigen-content ID vaccine is safe, well-tolerated and as immunogenic as IM standard-dose influenza vaccine.

Immunogenicity and protection of oral influenza vaccines formulated into microparticles

Influenza is a deadly disease affecting humans and animals. It is recommended that every individual should be vaccinated annually against influenza. Considering the frequency of administration of this vaccine, we have explored the oral route of vaccination with a microparticulate formulation. Microparticles containing inactivated influenza A/PR/34/8 H1N1 virus with Eudragit S and trehalose as a matrix were prepared using the Buchi spray dryer. Particle size distribution of microparticles was measured and the bioactivity of vaccine in a microparticle form was analyzed using a hemagglutination activity test. Furthermore, the efficacy of microparticle vaccines was evaluated in vivo in Balb/c mice. Analysis of serum samples showed that microparticles resulted in enhanced antigen-specific immunoglobulin G (IgG), IgG1, and IgG2a antibodies. Upon challenge with homologous and heterologous influenza viruses, microparticle vaccines showed significantly increased levels of protection. Use of microparticles to deliver vaccines could be a promising tool for the development of an oral influenza vaccine.

Acceptability of Intanza® 15 μg intradermal influenza vaccine in Belgium during the 2010-2011 influenza season

INTRODUCTION

Intradermal (ID) influenza vaccination induces an enhanced immune response in the elderly when compared with intramuscular (IM) vaccination. In 2009, an ID seasonal influenza vaccine (Intanza(®) [Sanofi Pasteur MSD, Lyon, France] 15 μg) was approved for use in individuals aged ≥ 60 years in Europe. This survey conducted in Belgium was the first in Europe to assess the acceptability of this vaccine in routine clinical practice by vaccinees and their general practitioners (GPs).

METHODS

GPs willing to use both the ID and IM influenza vaccines were selected during the 2010-2011 influenza season. Each GP recruited ≤ 10 patients aged ≥ 60 years who received the ID vaccine. Vaccinees and GPs completed questionnaires about their opinions on influenza vaccination and the acceptability of the ID influenza vaccine.

RESULTS

In total, 105 GPs and 837 vaccinees completed questionnaires. A high proportion of vaccinees (40.3%) was aged ≥ 75 years, and 95.5% had been vaccinated the previous year. The majority of vaccinees was very satisfied (70.0%) or satisfied (27.9%) with the ID vaccine. The main reasons for the high satisfaction rate were that the injection was not very painful, administration was quick, and the vaccinee felt confident about the micro-needle injection system. Most vaccinees (91.1%) who had previously received IM influenza vaccination preferred the ID vaccine, and 98.5% of vaccinees reported they would consider receiving the ID vaccine the following year. The majority of GPs was very satisfied (78.6%) or satisfied (18.4%) with the ID vaccine, and most GPs (87.6%) expressed a preference for the ID vaccine over IM influenza vaccine.

CONCLUSION

The ID influenza vaccine was well accepted by vaccinees and their GPs, who expressed a preference for the ID vaccine over conventional IM influenza vaccine. The availability of the ID influenza vaccine may help to improve uptake of seasonal influenza vaccination in the elderly.

Acceptance and safety of the intradermal influenza vaccine among the elderly in Italy: an on-field national study

INTRODUCTION

An observational multicenter study was carried out in Italy, to evaluate the acceptability and safety of the new intradermal (ID) influenza vaccine (Intanza Sanofi Pasteur SA, Lyon, France) among subjects aged≥60 years, compared with that of other intramuscular (IM) influenza vaccines. Compliance with the use of the ID vaccine by healthcare professionals was also assessed.

METHODS

A previously validated and self-administered questionnaire, Vaccinees' Perception of Injection (VAPI®), consisting of 21 questions, mainly focused on four dimensions (bother, arm movements, sleep, and acceptability), was administered to >1,600 individuals with spontaneous access to outpatient clinics, located in Northern, Central, and Southern Italy, to evaluate the acceptance of the vaccines. Occurrence of solicited and unsolicited side effects and of serious adverse events was assessed in a subset of subjects (n=500), using a clinical diary filled in by vaccinees following immunization. Compliance with the new ID vaccine by healthcare professionals was investigated using an ad-hoc questionnaire.

RESULTS

A very favorable opinion concerning the acceptability of both the vaccines under survey, with the most positive answers ranging between 75.5% and 94.9%, was registered within the study population. Also the compliance by healthcare professionals (n=130) with the novel ID vaccine was favorable. No serious adverse event occurred during the 6-month follow-up period. The frequency of solicited systemic reactions was comparable between the two study groups, while solicited local reactions were significantly higher in the ID-vaccine group than in the IM-vaccine group, even if at values lower than those reported in phase 3 clinical trials (ranges=18.5-32.6% vs. 29.5-70.9%). These local events were mild and transient, thus without any clinical relevance.

CONCLUSION

The novel ID influenza vaccine can be widely recommended in clinical practice, representing a useful tool to improve immunization coverage rates, and thus the control of influenza.

Acceptance and opinions of Intanza/IDflu intradermal influenza vaccine in the Czech Republic and Turkey

INTRODUCTION

Intanza(®)/IDflu(®) (Sanofi Pasteur SA, Lyon, France), a split-virion, trivalent influenza vaccine delivered by intradermal injection with a microinjection system, became available in adults 18-59 years of age (9 μg) and ≥60 years of age (15 μg) as of the 2010/2011 northern hemisphere influenza season.

METHODS

This study assessed the acceptability of intradermal vaccination with Intanza/IDflu in routine clinical practice in adult vaccinees and their vaccine prescribers. Vaccine prescribers and adults who had elected to be vaccinated with Intanza/IDflu during the 2010/2011 northern hemisphere influenza season were recruited to complete surveys about their opinions of influenza vaccination and their acceptance of the intradermal vaccination. Czech subjects 18-59 years of age were vaccinated with the 9 μg formulation and those ≥60 years of age with the 15 μg formulation of Intanza/IDflu. All Turkish subjects were vaccinated with the 9 μg formulation, as Intanza/IDflu 15 μg was not available in Turkey at the time the survey was conducted.

RESULTS

One thousand and twelve vaccinees and 28 vaccine prescribers in the Czech Republic, and 249 vaccinees and 15 vaccine prescribers in Turkey completed questionnaires. Overall, 96.1% of vaccinees were satisfied or very satisfied with Intanza/IDflu. The main reason for satisfaction was that the injection was considered minimally painful. Most (93.9%) vaccinees reported that they would prefer to receive the same vaccination next year. Furthermore, 95.3% of vaccine prescribers were satisfied or very satisfied with the intradermal vaccine, and 82.6% preferred intradermal over intramuscular vaccination.

CONCLUSIONS

Intradermal vaccination for seasonal influenza using Intanza/IDflu is well accepted by adult vaccinees and vaccine prescribers. By providing an additional, well-accepted method, Intanza/IDflu might help increase seasonal influenza vaccination rates in adults.