Immunogenicity and safety of concomitant administration of a measles, mumps and rubella vaccine (M-M-RvaxPro) and a varicella vaccine (VARIVAX) by intramuscular or subcutaneous routes at separate injection sites: a randomised clinical trial

Recombinant measles virus expressing prefusion spike protein stabilized by six rather than two prolines is more efficacious against SARS-CoV-2 infection

Measles virus (MeV) has been an excellent vector platform for delivering vaccines against many pathogens because of its high safety and efficacy, and induction of long-lived immunity. Early in the COVID-19 pandemic, a recombinant MeV (rMeV) expressing the prefusion full-length spike protein stabilized by two prolines (TMV-083) was developed and tested in phase 1 and 1/2 clinical trials but was discontinued because of insufficient immunogenicity and a low seroconversion rate in adults. Here, we compared the immunogenicity of rMeV expressing a soluble prefusion spike (preS) protein stabilized by two prolines (rMeV-preS-2P) with a rMeV expressing a soluble preS protein stabilized by six prolines (rMeV-preS-6P). We found that rMeV-preS-6P expressed approximately five times more preS than rMeV-preS-2P in cell culture. Importantly, rMeV-preS-6P induced 30-60 and six times more serum immunoglobulin G and neutralizing antibody than rMeV-preS-2P, respectively, in IFNAR-/- mice. IFNAR-/- mice immunized with rMeV-preS-6P were completely protected from challenge with a mouse-adapted SARS-CoV-2, whereas those immunized with rMeV-preS-2P were partially protected. In addition, hamsters immunized with rMeV-preS-6P were completely protected from the challenge with a Delta variant of SARS-CoV-2. Our results demonstrate that rMeV-preS-6P is significantly more efficacious than rMeV-preS-2P, highlighting the value of using preS-6P as the antigen for developing vaccines against SARS-CoV-2.

Recombinant Simian Varicella Virus-Simian Immunodeficiency Virus Vaccine Induces T and B Cell Functions and Provides Partial Protection against Repeated Mucosal SIV Challenges in Rhesus Macaques

HIV vaccine mediated efficacy, using an expanded live attenuated recombinant varicella virus-vectored SIV rSVV-SIVgag/env vaccine prime with adjuvanted SIV-Env and SIV-Gag protein boosts, was evaluated in a female rhesus macaques (RM) model against repeated intravaginal SIV challenges. Vaccination induced anti-SIV IgG responses and neutralizing antibodies were found in all vaccinated RMs. Three of the eight vaccinated RM remained uninfected (vaccinated and protected, VP) after 13 repeated challenges with the pathogenic SIVmac251-CX-1. The remaining five vaccinated and infected (VI) macaques had significantly reduced plasma viral loads compared with the infected controls (IC). A significant increase in systemic central memory CD4+ T cells and mucosal CD8+ effector memory T-cell responses was detected in vaccinated RMs compared to controls. Variability in lymph node SIV-Gag and Env specific CD4+ and CD8+ T cell cytokine responses were detected in the VI RMs while all three VP RMs had more durable cytokine responses following vaccination and prior to challenge. VI RMs demonstrated predominately SIV-specific monofunctional cytokine responses while the VP RMs generated polyfunctional cytokine responses. This study demonstrates that varicella virus-vectored SIV vaccination with protein boosts induces a 37.5% efficacy rate against pathogenic SIV challenge by generating mucosal memory, virus specific neutralizing antibodies, binding antibodies, and polyfunctional T-cell responses.

Efficacy of Western, Eastern, and Venezuelan Equine Encephalitis (WEVEE) Virus-Replicon Particle (VRP) Vaccine against WEEV in a Non-Human Primate Animal Model

The purpose of this study was to evaluate the effects of the route of administration on the immunogenicity and efficacy of a combined western, eastern, and Venezuelan equine encephalitis (WEVEE) virus-like replicon particle (VRP) vaccine in cynomolgus macaques. The vaccine consisted of equal amounts of WEEV, EEEV, and VEEV VRPs. Thirty-three animals were randomly assigned to five treatment or control groups. Animals were vaccinated with two doses of WEVEE VRPs or the control 28 days apart. Blood was collected 28 days following primary vaccination and 21 days following boost vaccination for analysis of the immune response to the WEVEE VRP vaccine. NHPs were challenged by aerosol 28 or 29 days following second vaccination with WEEV CBA87. Vaccination with two doses of WEVEE VRP was immunogenic and resulted in neutralizing antibody responses specific for VEEV, EEEV and WEEV. None of the vaccinated animals met euthanasia criteria following aerosol exposure to WEEV CBA87. However, one NHP control (total of 11 controls) met euthanasia criteria after infection with WEEV CBA87. Statistically significant differences in median fever hours were noted in control NHPs compared to vaccinated NHPs, providing a quantitative measure of infection and efficacy of the vaccine against a WEEV challenge. Alterations in lymphocytes, monocytes, and neutrophils were observed. Lymphopenia was observed in control NHPs.

In vivo fate and intracellular trafficking of vaccine delivery systems

With the pandemic of severe acute respiratory syndrome coronavirus 2, vaccine delivery systems emerged as a core technology for global public health. Given that antigen processing takes place inside the cell, the intracellular delivery and trafficking of a vaccine antigen will contribute to vaccine efficiency. Investigations focusing on the in vivo behavior and intracellular transport of vaccines have improved our understanding of the mechanisms relevant to vaccine delivery systems and facilitated the design of novel potent vaccine platforms. In this review, we cover the intracellular trafficking and in vivo fate of vaccines administered via various routes and delivery systems. To improve immune responses, researchers have used various strategies to modulate vaccine platforms and intracellular trafficking. In addition to progress in vaccine trafficking studies, the challenges and future perspectives for designing next-generation vaccines are discussed.

Prevention of measles, mumps and rubella: 40 years of global experience with M-M-RII

Measles, mumps, and rubella are highly contagious diseases that caused significant global mortality and morbidity in the pre-vaccine era. Since its first approval in the United States over 40 years ago, M-M-R_II has been used in >75 countries for prevention of these diseases. The vaccine has been part of immunization programs that have achieved dramatic global reductions in case numbers and mortality rates, as well as the elimination of measles and rubella in several countries and regions. This report summarizes over four decades of global safety, immunogenicity, efficacy, and effectiveness data for the vaccine. We include studies on the use of M-M-R_II in different age groups, concomitant use with other routine childhood vaccines, administration via different routes, persistence of immunity, and vaccine effectiveness during outbreaks of measles and mumps. We conclude that M-M-R_II is well tolerated and has shown consistently high performance during routine use in multiple countries, in randomized controlled trials with diverse designs, and in outbreak settings, including use as measles postexposure prophylaxis. Physicians, parents, and the public can continue to have a high degree of confidence in the use of M-M-R_II as a vital part of global public health programs.

Route of Vaccine Administration Alters Antigen Trafficking but Not Innate or Adaptive Immunity

Although intramuscular (i.m.) administration is the most commonly used route for licensed vaccines, subcutaneous (s.c.) delivery is being explored for several new vaccines under development. Here, we use rhesus macaques, physiologically relevant to humans, to identify the anatomical compartments and early immune processes engaged in the response to immunization via the two routes. Administration of fluorescently labeled HIV-1 envelope glycoprotein trimers displayed on liposomes enables visualization of targeted cells and tissues. Both s.c. and i.m. routes induce efficient immune cell infiltration, activation, and antigen uptake, functions that are tightly restricted to the skin and muscle, respectively. Antigen is also transported to different lymph nodes depending on route. However, these early differences do not translate into significant differences in the magnitude or quality of antigen-specific cellular and humoral responses over time. Thus, although some distinct immunological differences are noted, the choice of route may instead be motivated by clinical practicality.

Subcutaneous vaccine administration - an outmoded practice

Subcutaneous vaccine (SC) administration is an outmoded practice which complicates vaccine administration recommendations. Local adverse events following immunization (AEFIs) are a recognized determinant of vaccine hesitancy/refusal which can lead to an increased prevalence of vaccine-preventable disease.

This extensive narrative review provides high-grade evidence that intramuscular (IM) administration of all vaccine types [adjuvanted, live virus and non-adjuvanted (inactivated whole cell, split cell and subunit)] significantly reduces the likelihood of local adverse events. This, combined with moderate grade evidence that IM injection generates significantly greater immune response compared with SC injection, allows a strong recommendation to be made for the IM injection of all vaccines except BCG and Rotavirus.

This will simplify vaccination practice, minimize the inadvertent misadministration of vaccines and potentially improve public trust in vaccination.

Vaccination Route as a Determinant of Protective Antibody Responses against Herpes Simplex Virus

Herpes simplex viruses (HSV) are significant global health problems associated with mucosal and neurologic disease. Prior experimental vaccines primarily elicited neutralizing antibodies targeting glycoprotein D (gD), but those that advanced to clinical efficacy trials have failed. Preclinical studies with an HSV-2 strain deleted in gD (ΔgD-2) administered subcutaneously demonstrated that it elicited a high titer, weakly neutralizing antibodies that activated Fcg receptors to mediate antibody-dependent cellular cytotoxicity (ADCC), and completely protected mice against lethal disease and latency following vaginal or skin challenge with HSV-1 or HSV-2. Vaccine efficacy, however, may be impacted by dose and route of immunization. Thus, the current studies were designed to compare immunogenicity and efficacy following different routes of vaccination with escalating doses of ΔgD-2. We compared ΔgD-2 with two other candidates: recombinant gD protein combined with aluminum hydroxide and monophosphoryl lipid A adjuvants and a replication-defective virus deleted in two proteins involved in viral replication, dl5-29. Compared to the subcutaneous route, intramuscular and/or intradermal immunization resulted in increased total HSV antibody responses for all three vaccines and boosted the ADCC, but not the neutralizing response to ΔgD and dl5-29. The adjuvanted gD protein vaccine provided only partial protection and failed to elicit ADCC independent of route of administration. In contrast, the increased ADCC following intramuscular or intradermal administration of DgD-2 or dl5-29 translated into significantly increased protection. The DgD-2 vaccine provided 100% protection at doses as low as 5 × 104 pfu when administered intramuscularly or intradermally, but not subcutaneously. However, administration of a combination of low dose subcutaneous DgD-2 and adjuvanted gD protein resulted in greater protection than low dose DgD-2 alone indicating that gD neutralizing antibodies may contribute to protection. Taken together, these results demonstrate that ADCC provides a more predictive correlate of protection against HSV challenge in mice and support intramuscular or intradermal routes of vaccination.

Dendritic Cells/Macrophages-Targeting Feature of Ebola Glycoprotein and its Potential as Immunological Facilitator for Antiviral Vaccine Approach

In the prevention of epidemic and pandemic viral infection, the use of the antiviral vaccine has been the most successful biotechnological and biomedical approach. In recent times, vaccine development studies have focused on recruiting and targeting immunogens to dendritic cells (DCs) and macrophages to induce innate and adaptive immune responses. Interestingly, Ebola virus (EBOV) glycoprotein (GP) has a strong binding affinity with DCs and macrophages. Shreds of evidence have also shown that the interaction between EBOV GP with DCs and macrophages leads to massive recruitment of DCs and macrophages capable of regulating innate and adaptive immune responses. Therefore, studies for the development of vaccine can utilize the affinity between EBOV GP and DCs/macrophages as a novel immunological approach to induce both innate and acquired immune responses. In this review, we will discuss the unique features of EBOV GP to target the DC, and its potential to elicit strong immune responses while targeting DCs/macrophages. This review hopes to suggest and stimulate thoughts of developing a stronger and effective DC-targeting vaccine for diverse virus infection using EBOV GP.

The how's and what's of vaccine reactogenicity

Reactogenicity represents the physical manifestation of the inflammatory response to vaccination, and can include injection-site pain, redness, swelling or induration at the injection site, as well as systemic symptoms, such as fever, myalgia, or headache. The experience of symptoms following vaccination can lead to needle fear, long-term negative attitudes and non-compliant behaviours, which undermine the public health impact of vaccination. This review presents current knowledge on the potential causes of reactogenicity, and how host characteristics, vaccine administration and composition factors can influence the development and perception of reactogenicity. The intent is to provide an overview of reactogenicity after vaccination to help the vaccine community, including healthcare professionals, in maintaining confidence in vaccines by promoting vaccination, setting expectations for vaccinees about what might occur after vaccination and reducing anxiety by managing the vaccination setting.

Immunogenicity and safety of intramuscular versus subcutaneous administration of a combined measles, mumps, rubella, and varicella vaccine to children 12 to 18 months of age

This randomized trial conducted in France compared intramuscular (IM) and subcutaneous (SC) administration of two doses of a measles, mumps, rubella, and varicella (MMRV) combination vaccine (ProQuad®) administered one month apart to 405 children 12–18 months of age (NCT00402831). The 2-dose regimen of MMRV administered IM was shown to be as immunogenic as the 2-dose regimen administered SC for all antigens 6 weeks post-vaccination for the subjects who were initially seronegative for measles, mumps, rubella, or varicella (lower bounds of the two-sided 95% CIs for the difference in response rates for all antigens greater than −10% [range −2.1 for varicella to −3.0 for mumps]). The antibody response rates for all vaccine antigens 6 weeks after the second dose of MMRV were > 99% in both the IM and SC groups. Fewer subjects in the IM group experienced injection-site AEs compared with the SC group (17.8% and 28.6% post-dose 1, and 20.4% and 29.5% post-dose 2, respectively). From Day 0 to Day 4 post-dose 2, fewer subjects reported erythema and swelling in the IM group than in the SC group (15.4% and 27.0%, and 6.0% and 12.5%, respectively). In both groups, most injection-site AEs started during the first four days after vaccination; their intensity was mainly mild or ≤2.5 cm. The rates of fever were comparable between the two groups after each dose of MMRV. In conclusion, two doses of the MMRV vaccine were highly immunogenic and well tolerated when administered either SC or IM.

ClinicalTrials.gov Identifier: NCT00402831

Needle-free delivery of measles virus vaccine to the lower respiratory tract of non-human primates elicits optimal immunity and protection

Needle-free measles virus vaccination by aerosol inhalation has many potential benefits. The current standard route of vaccination is subcutaneous injection, whereas measles virus is an airborne pathogen. However, the target cells that support replication of live-attenuated measles virus vaccines in the respiratory tract are largely unknown. The aims of this study were to assess the in vivo tropism of live-attenuated measles virus and determine whether respiratory measles virus vaccination should target the upper or lower respiratory tract. Four groups of twelve cynomolgus macaques were immunized with 10⁴ TCID₅₀ of recombinant measles virus vaccine strain Edmonston-Zagreb expressing enhanced green fluorescent protein. The vaccine virus was grown in MRC-5 cells and formulated with identical stabilizers and excipients as used in the commercial MV^EZ vaccine produced by the Serum Institute of India. Animals were immunized by hypodermic injection, intra-tracheal inoculation, intra-nasal instillation, or aerosol inhalation. In each group six animals were euthanized at early time points post-vaccination, whereas the other six were followed for 14 months to assess immunogenicity and protection from challenge infection with wild-type measles virus. At early time-points, enhanced green fluorescent protein-positive measles virus-infected cells were detected locally in the muscle, nasal tissues, lungs, and draining lymph nodes. Systemic vaccine virus replication and viremia were virtually absent. Infected macrophages, dendritic cells and tissue-resident lymphocytes predominated. Exclusive delivery of vaccine virus to the lower respiratory tract resulted in highest immunogenicity and protection. This study sheds light on the tropism of a live-attenuated measles virus vaccine and identifies the alveolar spaces as the optimal site for respiratory delivery of measles virus vaccine.

Safety and Immunogenicity of M-M-RII (Combination Measles-Mumps-Rubella Vaccine) in Clinical Trials of Healthy Children Conducted Between 1988 and 2009

BACKGROUND

M-M-RII, a combination measles, mumps and rubella vaccine, was licensed in the United States in 1978 based on data from several clinical trials that demonstrated that the safety and immunogenicity of the vaccine were comparable to the component monovalent vaccines and to the previous trivalent combination vaccine.

METHODS

Safety and immunogenicity data from 23 postlicensure clinical trials conducted with M-M-RII between 1988 and 2009 were summarized. A total of 12,901 children who received only a first dose, 920 children who received a first and second dose and 400 children who received only a second dose were evaluated.

RESULTS

The vaccine was generally well tolerated among children who received a first and/or second dose of M-M-RII. During the 28-42-day follow-up after dose 1 and dose 2, the median rate of temperatures ≥102°F (oral equivalent) was 24.8% and 13.0% and the median rate of measles/rubella-like rash was 3.2% and 0.5%, respectively. The median rate of injection-site reactions during the first 5 days postdose 1 and postdose 2 was 17.3% and 42.7%, respectively. The seroconversion rates (enzyme-linked immunosorbent assay) after dose 1 were remarkably consistent from study to study between 1988 and 2009 (92.8%-100% for measles, 97.7%-100% for mumps and 92.8%-100% for rubella). A trend test showed that there was no change in the immunogenicity of the vaccine over the 21-year period.

CONCLUSIONS

The results of this analysis demonstrate that M-M-RII is well tolerated and immunogenic. The vaccine performed consistently over 21 years of evaluation in clinical trials.

Effect of vaccine administration modality on immunogenicity and efficacy

The many factors impacting the efficacy of a vaccine can be broadly divided into three categories: features of the vaccine itself, including immunogen design, vaccine type, formulation, adjuvant and dosing; individual variations among vaccine recipients and vaccine administration-related parameters. While much literature exists related to vaccines, and recently systems biology has started to dissect the impact of individual subject variation on vaccine efficacy, few studies have focused on the role of vaccine administration-related parameters on vaccine efficacy. Parenteral and mucosal vaccinations are traditional approaches for licensed vaccines; novel vaccine delivery approaches, including needless injection and adjuvant formulations, are being developed to further improve vaccine safety and efficacy. This review provides a brief summary of vaccine administration-related factors, including vaccination approach, delivery route and method of administration, to gain a better understanding of their potential impact on the safety and immunogenicity of candidate vaccines.

Comparison of intramuscular and subcutaneous administration of a herpes zoster live-attenuated vaccine in adults aged ≥50 years: a randomised non-inferiority clinical trial

Zostavax(®) is a live, attenuated varicella zoster virus (VZV) vaccine developed specifically for the prevention of HZ and PHN in individuals aged ≥50 years. During the clinical development of Zostavax, which was mainly in the US, the vaccine was administrated by the subcutaneous (SC) route. In Europe, many healthcare professionals prefer administering vaccines by the intramuscular (IM) route. This was an open-label, randomised trial conducted in 354 subjects aged ≥50 years. The primary objectives were to demonstrate that IM administration is both non-inferior to SC administration in terms of 4-week post-vaccination geometric mean titres (GMTs), and elicits an acceptable geometric mean fold-rise (GMFR) of antibody titres measured by glycoprotein enzyme-linked immunosorbent assay. Pre-specified non-inferiority was set as the lower bound of the 95% confidence interval (CI) of the GMT ratio (IM/SC) being >0.67. An acceptable GMFR for the IM route was pre-specified as the lower bound of its 95% CI being >1.4. Description of the VZV immune response using the interferon-gamma enzyme-linked immunospot (IFN-γ ELISPOT) assay and of the safety were secondary objectives. Participants were randomised to IM or SC administration (1:1). The baseline demographics were comparable between groups; mean age: 62.6 years (range: 50.0-90.5). The primary immunogenicity objectives were met (per protocol analysis): GMT ratio (IM/SC): 1.05 (95% CI: 0.93-1.18); GMFR: 2.7 (2.4-3.0). VZV immune response using IFN-γ ELISPOT were comparable between groups. Frequencies of systemic adverse events were comparable between groups. Injection-site reactions were less frequent with IM than SC route: erythema (15.9% versus 52.5%), pain (25.6% versus 39.5%) and swelling (13.6% versus 37.3%), respectively. In adults aged ≥50 years, IM administration of Zostavax elicited similar immune responses to SC administration and was well tolerated, with fewer injection-site reactions than with SC administration.

Live-attenuated measles virus vaccine targets dendritic cells and macrophages in muscle of nonhuman primates

Although live-attenuated measles virus (MV) vaccines have been used successfully for over 50 years, the target cells that sustain virus replication in vivo are still unknown. We generated a reverse genetics system for the live-attenuated MV vaccine strain Edmonston-Zagreb (EZ), allowing recovery of recombinant (r)MV(EZ). Three recombinant viruses were generated that contained the open reading frame encoding enhanced green fluorescent protein (EGFP) within an additional transcriptional unit (ATU) at various positions within the genome. rMV(EZ)EGFP(1), rMV(EZ)EGFP(3), and rMV(EZ)EGFP(6) contained the ATU upstream of the N gene, following the P gene, and following the H gene, respectively. The viruses were compared in vitro by growth curves, which indicated that rMV(EZ)EGFP(1) was overattenuated. Intratracheal infection of cynomolgus macaques with these recombinant viruses revealed differences in immunogenicity. rMV(EZ)EGFP(1) and rMV(EZ)EGFP(6) did not induce satisfactory serum antibody responses, whereas both in vitro and in vivo rMV(EZ)EGFP(3) was functionally equivalent to the commercial MV(EZ)-containing vaccine. Intramuscular vaccination of macaques with rMV(EZ)EGFP(3) resulted in the identification of EGFP(+) cells in the muscle at days 3, 5, and 7 postvaccination. Phenotypic characterization of these cells demonstrated that muscle cells were not infected and that dendritic cells and macrophages were the predominant target cells of live-attenuated MV.

IMPORTANCE

Even though MV strain Edmonston-Zagreb has long been used as a live-attenuated vaccine (LAV) to protect against measles, nothing is known about the primary cells in which the virus replicates in vivo. This is vital information given the push to move toward needle-free routes of vaccination, since vaccine virus replication is essential for vaccination efficacy. We have generated a number of recombinant MV strains expressing enhanced green fluorescent protein. The virus that best mimicked the nonrecombinant vaccine virus was formulated according to protocols for production of commercial vaccine virus batches, and was subsequently used to assess viral tropism in nonhuman primates. The virus primarily replicated in professional antigen-presenting cells, which may explain why this LAV is so immunogenic and efficacious.

Vaccines for post-exposure prophylaxis against varicella (chickenpox) in children and adults

BACKGROUND

The prevention of varicella (chickenpox) using live attenuated varicella vaccines has been demonstrated both in randomised controlled trials (RCTs) and in population-based immunisation programmes in countries such as the United States and Australia. Many countries do not routinely immunise children against varicella and exposures continue to occur. Although the disease is often mild, complications such as secondary bacterial infection, pneumonitis and encephalitis occur in about 1% of cases, usually leading to hospitalisation. The use of varicella vaccine in persons who have recently been exposed to the varicella zoster virus has been studied as a form of post-exposure prophylaxis (PEP).

OBJECTIVES

To assess the efficacy and safety of vaccines for use as PEP for the prevention of varicella in children and adults.

SEARCH METHODS

We searched CENTRAL (2014, Issue 1), MEDLINE (1966 to March week 1, 2014), EMBASE (January 1990 to March 2014) and LILACS (1982 to March 2014). We searched for unpublished trials registered on the clinicaltrials.gov and WHO ICTRP websites.

SELECTION CRITERIA

RCTs and quasi-RCTs of varicella vaccine for PEP compared with placebo or no intervention. The outcome measures were efficacy in prevention of clinical cases and/or laboratory-confirmed clinical cases and adverse events following vaccination.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted and analysed data using Review Manager software.

MAIN RESULTS

We identified three trials involving 110 healthy children who were siblings of household contacts. The included trials varied in study quality, vaccine used, length of follow-up and outcomes measured and, as such, were not suitable for meta-analysis. We identified high or unclear risk of bias in two of the three included studies. Overall, 13 out of 56 vaccine recipients (23%) developed varicella compared with 42 out of 54 placebo (or no vaccine) recipients (78%). Of the vaccine recipients who developed varicella, the majority only had mild disease (with fewer than 50 skin lesions). In the three trials, most participants received PEP within three days following exposure; too few participants were vaccinated four to five days post-exposure to ascertain the efficacy of vaccine given more than three days after exposure. No included trial reported on adverse events following immunisation.

AUTHORS' CONCLUSIONS

These small trials suggest varicella vaccine administered within three days to children following household contact with a varicella case reduces infection rates and severity of cases. We identified no RCTs for adolescents or adults. Safety was not adequately addressed.

Evaluation of a commercial glycoprotein enzyme-linked immunosorbent assay for measuring vaccine immunity to varicella

PURPOSE

To evaluate a recently marketed commercial glycoprotein enzyme-linked immunosorbent assay (gpEIA) kit, the VaccZyme™ VZV gpEIA, for measuring the immunity of varicella-vaccinated children.

MATERIALS AND METHODS

We investigated the accuracy and reproducibility of the VaccZyme™ VZV gpEIA kit for the detection of antibodies to VZV. We also examined the sensitivity, specificity, and correlation between antibody titers calculated with gpEIA versus fluorescent antibody to membrane antigen (FAMA) by using sera of 349 children, ranging from 1 to 6 years old.

RESULTS

VaccZyme™ VZV gpEIA gave precise and reproducible intra- and inter-assay results. FAMA and gpEIA titers showed a linear correlation (Pearson correlation coefficient=0.987). The sensitivity and specificity of the VaccZyme™ gpEIA was 31.4% and 100%, respectively, when the guidelines of the gpEIA (<100 mIU/mL) and FAMA 1:4 were adopted as cutoff values. However, the maximum sensitivity and specificity were 88.9% and 95.1%, respectively, with the highest correlation (κ=0.840), if the cutoff values were set with gpEIA at 49.7 mIU/mL and FAMA 1:16.

CONCLUSION

These results demonstrate that the VaccZyme™ VZV gpEIA kit gave precise and reproducible data for measuring antibody titer after varicella vaccination. The results also showed that the antibody titer calculated with the VaccZyme™ gpEIA kit strongly correlated with the FAMA titer. However, cutoff values should be re-optimized for the evaluation of vaccine immunity.

Primary versus secondary failure after varicella vaccination: implications for interval between 2 doses

BACKGROUND

Two-dose varicella vaccination is recommended for optimal control of varicella in populations with high (>90%) 1-dose coverage. Optimal timing of the second dose may depend on whether breakthrough varicella results from primary vaccine failure (no protective immunity after vaccination) or secondary vaccine failure (waning protective immunity).

METHODS

Published literature (1995 to 2012) on vaccine failure after varicella vaccination cited in PubMed and other online sources was reviewed.

RESULTS

Nineteen publications detailed 21 varicella outbreaks with breakthrough varicella rates ranging from 0% to 42%; the publications showed no consistent trend between breakthrough varicella rate and time since vaccination.

CONCLUSIONS

Literature to date indicates a relatively high rate of primary vaccine failure and limited evidence of secondary vaccine failure among 1-dose varicella vaccine recipients, suggesting that a short interval between 2 doses might be preferable in countries considering implementation of universal varicella vaccination to reduce breakthrough varicella. However, any potential disruption to well-established vaccination schedules should be considered.

Safety of a 2-dose regimen of a combined measles, mumps, rubella and varicella live vaccine manufactured with recombinant human albumin

BACKGROUND

ProQuad, a vaccine containing antigens from M-M-RVAXPRO (measles, mumps and rubella vaccine) and VARIVAX (varicella vaccine), is indicated for simultaneous vaccination against measles, mumps, rubella and varicella (MMRV) in individuals from 12 months of age. To eliminate blood-derived products of human origin from the manufacturing process of the MMRV vaccine, recombinant human albumin was selected as a replacement for human serum albumin.

METHODS

This open-label, multicenter clinical trial (clinicaltrials.gov identifier NCT00560755) was designed to describe the safety profile of a 2-dose schedule of the MMRV vaccine at a 1-month interval in healthy children aged 12-22 months.

RESULTS

In total, 3388 children received at least 1 dose of the MMRV vaccine. Overall, 3376 (99.65%) children were included in the post-dose 1 safety analysis and 3342 (98.64%) in the post-dose 2 safety analysis. After doses 1 and 2, the frequencies of children experiencing solicited injection-site reactions (post-dose 1: erythema 14.31%; swelling 5.57% and pain 10.31%; post-dose 2: erythema 30.46%; swelling 13.23% and pain 11.49%), rashes of interest (post-dose 1: 11.4%; post-dose 2: 2.78%), vaccine-related nonserious systemic adverse events (post-dose 1: 34.86%; post-dose 2: 13.4%) and temperature ≥39.4 °C (post-dose 1: 25.24%; post-dose 2: 12.06%) were consistent with those observed in previous studies of the MMRV vaccine manufactured with human serum albumin. Neither serious allergic-type adverse events nor anaphylactic reactions were reported.

CONCLUSION

The results confirm the good safety profiles of MMRV and of measles, mumps and rubella vaccines manufactured with recombinant human albumin.

Safety, immunogenicity and immediate pain of intramuscular versus subcutaneous administration of a measles-mumps-rubella-varicella vaccine to children aged 11-21 months

This study compared intramuscular and subcutaneous administration of two doses of measles-mumps-rubella-varicella (MMRV) combination vaccine (Priorix-Tetra, GlaxoSmithKline Biologicals) in children. Healthy children (N = 328) were randomised to receive MMRV either intramuscularly or subcutaneously. Reactogenicity was similar between treatment groups for immediate vaccination pain, vaccination site pain, redness and incidence of fever and rashes. Slightly less vaccination site swelling occurred during days 0-3 of the post-vaccination period after intramuscular administration. Seroconversion rates for all components, 42-56 days post-dose 2, ranged from 99.3% to 100% in the intramuscular group and from 98.6% to 100% in the subcutaneous. Cell-mediated immunity data supported the humoral immunogenicity findings. In summary, the MMRV vaccine is well tolerated and highly immunogenic when administered either subcutaneously or intramuscularly to children in the second year of life.