Comparison of the levels of immunogenicity and safety of Zostavax in adults 50 to 59 years old and in adults 60 years old or older

Insights into the pathogenesis of varicella viruses

Purpose of review

Varicella zoster virus (VZV) is a highly contagious, neurotropic alpha herpes virus that causes varicella (chickenpox). VZV establishes lifelong latency in the sensory ganglia from which it can reactivate to induce herpes zoster (HZ), a painful disease that primarily affects older individuals and those who are immune-suppressed. Given that VZV infection is highly specific to humans, developing a reliable in vivo model that recapitulates the hallmarks of VZV infection has been challenging. Simian Varicella Virus (SVV) infection in nonhuman primates reproduces the cardinal features of VZV infections in humans and allows the study of varicella virus pathogenesis in the natural host. In this review, we summarize our current knowledge about genomic and virion structure of varicelloviruses as well as viral pathogenesis and antiviral immune responses during acute infection, latency and reactivation. We also examine the immune evasion mechanisms developed by varicelloviruses to escape the host immune responses and the current vaccines available for protecting individuals against chickenpox and herpes zoster.

Recent findings

Data from recent studies suggest that infected T cells are important for viral dissemination to the cutaneous sites of infection as well as site of latency and that a viral latency-associated transcript might play a role in the transition from lytic infection to latency and then reactivation.

Summary

Recent studies have provided exciting insights into mechanisms of varicelloviruses pathogenesis such as the critical role of T cells in VZV/SVV dissemination from the respiratory mucosa to the skin and the sensory ganglia; the ability of VZV/SVV to interfere with host defense; and the identification of VLT transcripts in latently infected ganglia. However, our understanding of these phenomena remains poorly understood. Therefore, it is critical that we continue to investigate host-pathogen interactions during varicelloviruses infection. These studies will lead to a deeper understanding of VZV biology as well as novel aspects of cell biology.

A framework for the systematic consideration of ethics, equity, feasibility, and acceptability in vaccine program recommendations

For the successful implementation of population-level recommendations, it is critical to consider the full spectrum of public health science, including clinical and programmatic factors. Current frameworks may identify various factors that should be examined when making evidence-informed vaccine-related recommendations. However, while most immunization guidelines systematically assess clinical factors, such as efficacy and safety of vaccines, there is no published framework outlining how to systematically assess programmatic factors, such as the ethics, equity, feasibility, and acceptability of recommendations. We have addressed this gap with the development of the EEFA (Ethics, Equity Feasibility, Acceptability) Framework, supported by evidence-informed tools, including Ethics Integrated Filters, Equity Matrix, Feasibility Matrix, and an Acceptability Matrix. The Framework and tools are based on five years of environmental scans, systematic reviews and surveys, and refined by expert and stakeholder consultations and feedback. For each programmatic factor, the EEFA Framework summarizes the minimum threshold for consideration and when further in-depth analysis may be required, which aspects of the factor should be considered, how to assess the factor using the supporting evidence-informed tools, and who should be consulted to complete the assessment. Research, particularly in the fields of vaccine acceptability and equity, has validated the utility and comprehensiveness of the tools. The Framework has been successfully used in Canada for clear, timely, transparent vaccine guidance with positive stakeholder feedback on its comprehensiveness, relevance and appropriateness. Applying the EEFA Framework allows for the systematic consideration of the spectrum of public health science without a delay in recommendations, complementing existing decision-making frameworks. This Framework will therefore be useful for advisory groups worldwide to integrate critical factors that could impact the successful and timely implementation of comprehensive, transparent recommendations, and will further the global objective of developing practical and evidence-informed immunization policies.

A unified evaluation of differential vaccine efficacy

Many infectious diseases are well prevented by proper vaccination. However, when a vaccine is not completely efficacious, there is great interest in determining how the vaccine effect differs in subgroups conditional on measured immune responses postvaccination and also according to the type of infecting agent (eg, strain of a virus). The former is often called correlate of protection (CoP) analysis, while the latter has been called sieve analysis. We propose a unified framework for simultaneously assessing CoP and sieve effects of a vaccine in a large Phase III randomized trial. We use flexible parametric models treating times to infection from different agents as competing risks and estimated maximum likelihood to fit the models. The parametric models under competing risks allow for estimation of both cumulative incidence-based contrasts and instantaneous rates. We outline the assumptions with which we can link the observable data to the causal contrasts of interest, propose hypothesis testing procedures, and evaluate our proposed methods in an extensive simulation study.

Diabetes as a risk factor for herpes zoster in adults: A synthetic literature review

AIM

The objective of this review was to evaluate the role of diabetes as a risk factor for herpes zoster (HZ) and to discuss implications of prevention by vaccination with available HZ vaccines.

METHODS

We reviewed studies that investigated the incidence rates of HZ in patients with diabetes. Papers in English or French published between January 2000 and December 2018 have been selected from PubMed and Google Scholarship by using appropriate key words.

RESULTS

The risk of HZ was significantly higher in patients with diabetes as compared to controls in 11 studies out of 16, although the magnitude of risk associated to diabetes varied across studies from 1.06 to 2.38 (p < 0.05). The incidence of HZ in patients with diabetes increased with age and was higher in women than in men. The incidence of the most common complication of HZ, i.e. post-herpetic neuralgia was also higher in patients with diabetes.

CONCLUSIONS

The presence of HZ adds supplementary complications to the pre-existing comorbidity in patients with diabetes. Investigating the impact of preventive measure by HZ vaccination is therefore of paramount importance in patients with diabetes.

Herpes zoster and the search for an effective vaccine

Primary infection with varicella zoster virus (VZV), an exclusively human neurotrophic alphaherpsesvirus, results in varicella, known more commonly as chickenpox. Like other alphaherpesviruses, VZV establishes latency in the sensory ganglia and can reactivate to cause herpes zoster (also known as shingles), a painful and debilitating disease, especially in elderly and immunocompromised individuals. The overall incidence of herpes zoster in Europe and the United States is three per 1000 people, but increases sharply after 60 years of age to 10 per 1000 people. Zostavax® is a vaccine approved by the Federal Drug Administration for the prevention of herpes zoster. Unfortunately, this vaccine reduces the incidence of disease by only 51% and the incidence of post-herpetic neuralgia by 66·5% when administered to those aged 60 and older. Moreover, it is contraindicated for individuals who are immunocompromised or receiving immunosuppressant treatments, although they are at higher risk for herpes zoster compared to immune-competent older individuals. This paper reviews VZV pathogenesis, host responses and current vaccines available to prevent herpes zoster.

Vaccines for preventing herpes zoster in older adults

BACKGROUND

Herpes zoster, also known as 'shingles', is a neurocutaneous disease characterised by the reactivation of the latent varicella zoster virus (VZV), the virus that causes chickenpox when immunity to VZV declines. It is an extremely painful condition that can last many weeks or months and it can significantly compromise the quality of life of affected individuals. The natural process of aging is associated with a reduction in cellular immunity and this predisposes older people to herpes zoster. Vaccination with an attenuated form of VZV activates specific T cell production avoiding viral reactivation. The Food and Drug Administration has approved a herpes zoster vaccine with an attenuated active virus for clinical use among older adults, which has been tested in large populations. A new adjuvanted recombinant VZV subunit zoster vaccine has also been tested. It consists of recombinant VZV glycoprotein E and a liposome-based AS01B adjuvant system. This new vaccine is not yet available for clinical use.

OBJECTIVES

To evaluate the effectiveness and safety of vaccination for preventing herpes zoster in older adults.

SEARCH METHODS

For this 2015 update, we searched the Cochrane Central Register of Controlled Trials (CENTRAL 2015, Issue 9), MEDLINE (1948 to the 3rd week of October 2015), EMBASE (2010 to October 2015), CINAHL (1981 to October 2015) and LILACS (1982 to October 2015).

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs comparing zoster vaccine with placebo or no vaccine, to prevent herpes zoster in older adults (mean age > 60 years).

DATA COLLECTION AND ANALYSIS

Two review authors independently collected and analysed data using a data extraction form. They also performed 'Risk of bias' assessment.

MAIN RESULTS

We identified 13 studies involving 69,916 participants. The largest study included 38,546 participants. All studies were conducted in high-income countries and included only healthy Caucasian individuals ≥ 60 years of age without immunosuppressive comorbidities. Ten studies used live attenuated varicella zoster virus (VZV) vaccines. Three studies tested a new type of vaccine not yet available for clinical use. We judged five of the included studies to be at low risk of bias.The incidence of herpes zoster, at up to three years of follow-up, was lower in participants who received the vaccine than in those who received a placebo: risk ratio (RR) 0.49; 95% confidence interval (CI) 0.43 to 0.56, risk difference (RD) 2%, number needed to treat to benefit (NNTB) 50; GRADE: moderate quality evidence. The vaccinated group had a higher incidence of mild to moderate intensity adverse events. These date came from one large study that included 38,546 people aged 60 years or older.A study including 8122 participants compared the new vaccine (not yet available) to the placebo; the group that received the new vaccine had a lower incidence of herpes zoster at 3.2 years of follow-up: RR 0.04, 95% CI 0.02 to 0.10, RD 3%, NNTB 33; GRADE: moderate quality evidence. The vaccinated group had a higher incidence of adverse events but most them were of mild to moderate intensity.All studies received funding from the pharmaceutical industry.

AUTHORS' CONCLUSIONS

Herpes zoster vaccine is effective in preventing herpes zoster disease and this protection can last three years. In general, zoster vaccine is well tolerated; it produces few systemic adverse events and injection site adverse events of mild to moderate intensity.There are studies of a new vaccine (with a VZV glycoproteic fraction plus adjuvant), which is currently not yet available for clinical use.

[Vaccines against Herpes zoster: Effectiveness, safety, and cost/benefit ratio]

CONTEXT

A vaccination against herpes zoster and its complication is available in France since June 2015. Its exact benefit for public health is still controversial and its level of protection is not optimal. All those reasons seem to suggest a low acceptation rate from general practitioners.

OBJECTIVE

To evaluate the effectiveness, the safety, and the cost/benefit ratio of the vaccination against herpes zoster in people aged 50 year or over.

DOCUMENTARY SOURCE

Systematic review in Medline and PubMed with research by key words: "herpes zoster vaccine", "zoster vaccine" and "post herpetic neuralgia vaccine".

SELECTION OF STUDIES

Randomized and observational studies published in English and French language have been selected by two readers.

RESULTS

On 1886 articles identified, 62 studies were included in this systematic review of which 21 randomized trials, 21 observational studies, and 17 medico-economic studies concerned the unadjuvanted vaccine. Considered studies showed an effectiveness of 50% against herpes zoster and 60% on post-herpetic neuralgia incidence of the unadjuvanted vaccine. Five randomized controlled studies were identified for the adjuvanted vaccine. The overall effectiveness of this vaccine was > 90% whatever the age of subjects including those over age 70 and 80. The medico-economic studies conducted in many countries have shown that vaccine policies were beneficial in individuals aged 60 years or over.

LIMITATION OF THE WORK

Most of data of effectiveness, and tolerance result from 2 large controlled studies only (SPS and ZEST) for the unadjuvanted vaccine and only one for the adjuvanted vaccine.

CONCLUSION

Despite controversy and few uncertainties, the vaccine significantly reduces herpes zoster and its complication incidence. In terms of public health objectives, it reduces the burden of the disease and has a positive medico-economic impact. Preliminary data concerning the adjuvanted vaccine, whilst very promising, are still too limited. Up to now, no group of people with particularly high risk of herpes zoster-related complication who will beneficiate the most of the vaccination has been identified yet and only an age criteria has been considered for the recommendation.

The immunogenicity and safety of zoster vaccine in Taiwanese adults

The efficacy and safety of ZOSTAVAX in subjects 60 years of age and older was established in the Shingles Prevention Study (SPS) and in subjects 50 to 59 years of age in the ZOSTAVAX Efficacy and Safety Trial (ZEST). We evaluated the safety and immunogenicity of ZOSTAVAX in a total of 150 Taiwanese subjects ≥50 years of age, who received a single dose of ZOSTAVAX. gpELISA was used to determine geometric mean titers (GMT) of the varicella-zoster virus (VZV) antibody. The geometric mean fold rise (GMFR) of the VZV antibody from the pre-vaccination to the 4 week post-vaccination time point was calculated. There was an overall increase in GMT from 128.45 to 391.85 at 4 weeks post-vaccination. The estimated GMFR was 3.05 (95% CI: 2.60 to 3.57).There were no serious adverse events for 28 days following vaccination. This study demonstrated the safety and immunogenicity of ZOSTAVAX among healthy Taiwanese adults.

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.

Zostavax : a subcutaneous vaccine for the prevention of herpes zoster

INTRODUCTION

Herpes zoster (HZ) occurs as a reactivation of dormant varicella zoster virus (VZV), and occurs more frequently in the aging population or the immunocompromised due to waning cell-mediated immunity. Up to 1 million cases of HZ are reported annually in the USA with an estimated 10 - 30% of the population being affected by shingles in their lifetime. HZ is a debilitating illness, and while mortality is low, morbidity remains a significant cause for concern with prevention efforts aimed at reducing VZV reactivation and its complications. The HZ vaccine was approved by the US Food and Drug Administration for individuals aged 50-years or older. However, the Center for Disease Control and Prevention's Advisory Committee for Immunization Practices recommends the vaccine in individuals aged 60-years or older.

AREAS COVERED

Recent literature investigating the efficacy and indications of live attenuated zoster vaccine.

EXPERT OPINION

Live attenuated zoster vaccine is safe and efficacious in preventing HZ and decreasing the morbidity associated with postherpetic neuralgia. The vaccine is FDA approved in individuals aged 50-years or older but further studies are warranted to investigate the vaccine's efficacy in immunosuppressed and immunocompromised patients.

Vaccines for preventing herpes zoster in older adults

BACKGROUND

Herpes zoster or, as it is commonly called, 'shingles' is a neurocutaneous disease characterised by the reactivation of varicella zoster virus (VZV), the virus that causes chickenpox, which is latent in the dorsal spinal ganglia when immunity to VZV declines. It is an extremely painful condition which can often last for many weeks or months, impairing the patient's quality of life. The natural aging process is associated with a reduction of cellular immunity which predisposes to herpes zoster. Vaccination with an attenuated form of VZV activates specific T cell production, therefore avoiding viral reactivation. A herpes zoster vaccine with an active virus has been approved for clinical use among older adults by the Food and Drug Administration and has been tested in large populations.

OBJECTIVES

To evaluate the effectiveness and safety of vaccination for preventing herpes zoster in older adults.

SEARCH METHODS

We searched the following sources for relevant studies: CENTRAL 2012, Issue 7, MEDLINE (1948 to July week 1, 2012), EMBASE (2010 to July 2012), LILACS (1982 to July 2012) and CINAHL (1981 to July 2012). We also reviewed reference lists of identified trials and reviews for additional studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs comparing zoster vaccine with placebo or no vaccine, to prevent herpes zoster in older adults (mean age > 60 years).

DATA COLLECTION AND ANALYSIS

Two review authors independently collected and analysed data using a data extraction form. They also carried out an assessment of risk of bias.

MAIN RESULTS

We identified eight RCTs with a total of 52,269 participants. Three studies were classified at low risk of bias. The main outcomes on effectiveness and safety were extracted from one clinical trial with a low risk of bias. Four studies compared zoster vaccine versus placebo; one study compared high-potency zoster vaccine versus low-potency zoster vaccine; one study compared refrigerated zoster vaccine versus frozen zoster vaccine; one study compared live zoster vaccine versus inactivated zoster vaccine and one study compared zoster vaccine versus pneumococcal polysaccharide vaccine (pneumo 23).Confirmed cases of herpes zoster were less frequent in patients who received the vaccine than in those who received a placebo: risk ratio (RR) 0.49 (95% confidence interval (CI) 0.43 to 0.56), with a risk difference (RD) of 2%, and number needed to treat to benefit (NNTB) of 50. Analyses according to age groups indicated a greater benefit in participants aged 60 to 69 years, RR 0.36 (95% CI 0.30 to 0.45) and in participants aged 70 years and over, RR 0.63 (95% CI 0.53 to 0.75). Vaccine-related systemic adverse effects were more frequent in the vaccinated group (RR 1.29, 95% CI 1.05 to 1.57, number needed to treat to harm (NNTH) = 100). The pooled data risk ratio for adverse effects for participants with one or more inoculation site adverse effect was RR 4.51 (95% CI 2.35 to 8.68), and the NNTH was 2.8 (95% CI 2.3 to 3.4). Side effects were more frequent in younger (60 to 69 years) than in older (70 years and over) participants.

AUTHORS' CONCLUSIONS

Herpes zoster vaccine is effective in preventing herpes zoster disease. Although vaccine benefits are larger in the younger age group (60 to 69 years), this is also the age group with more adverse events. In general, zoster vaccine is well tolerated; it produces few systemic adverse events and injection site adverse effects of mild to moderate intensity.

Adaptation of a previously validated vaccination report card for use in adult vaccine clinical trials to align with the 2007 FDA Toxicity Grading Scale Guidance

The Adult/Adolescent Vaccination Report Card (VRC) was developed and validated by Merck in 1998 for use in vaccine clinical trials to collect information from trial subjects on complaints for both local and systemic events after vaccination. This short report describes the revision to the original validated VRC in order to align with the guidelines outlined in the 2007 FDA Toxicity Grading Scale for Healthy Adult and Adolescent Volunteers Enrolled in Preventive Vaccine Clinical Trials. Since the VRC elicits trial subjects' self-reports of any adverse experiences (AE) occurring post vaccination, it was important that subsequent modifications of the VRC retained the original user-friendly characteristics while gathering the appropriate information to align with the FDA Guidance. A convenience sample of 15 participants (71% females, 87% white and mean (SD) age 45 (13) years was recruited to obtain feedback in order to revise the Adult/Adolescent VRC. Based on the feedback received, the following were slightly revised: ruler for the measurements of local systemic reactions, severity ratings, and general instructions. The revised VRC is currently being used in Merck vaccine clinical trials.

An unusual case of multi-recurrent herpes zoster (Hz): a case report

AIMS

We report a case of multi-recurrent herpes zoster in a 53-year-old Caucasian woman treated repeatedly at the Faculty Hospital Hradec Kralove, Czech Republic over the years 2009 - 2011.

METHODS

Specific PCR methods targeting single nucleotide polymorphisms (SNPs) in open reading frames (ORF) 38, 54 and 62 were utilized to determine vaccine or wild type varicella-zoster (VZV) strains followed by SNPs analysis using two amplicons in ORF 22 and/or ORF 21/ORF 50. Additional genotyping in ORF 1, 6, 9 and 28 was subsequently performed due to the unusual results.

RESULTS

Three sets of clinical specimens from one patient (from hospital visits 2, 3 and 4) were analyzed and the presence of an unusual wild-type strain of VZV was discovered. The VZV strain isolated from the lesions bears a combination of markers characteristic both for Mosaic 2 (M2) and European 1 (E1) wild-type VZV strains.

CONCLUSION

This is the first report of atypical wild-type VZV strain circulating currently in Czech Republic.

Efficacy, safety, and tolerability of herpes zoster vaccine in persons aged 50-59 years

BACKGROUND

Herpes zoster (HZ) adversely affects individuals aged 50-59, but vaccine efficacy has not been assessed in this population. This study was designed to determine the efficacy, safety, and tolerability of zoster vaccine for preventing HZ in persons aged 50-59 years.

METHODS

This was a randomized, double-blind, placebo-controlled study of 22 439 subjects aged 50-59 years conducted in North America and Europe. Subjects were given 1 dose of licensed zoster vaccine (ZV) (Zostavax; Merck) and followed for occurrence of HZ for ≥1 year (mean, 1.3 years) postvaccination until accrual of ≥96 confirmed HZ cases (as determined by testing lesions swabs for varicella zoster virus DNA by polymerase chain reaction). Subjects were followed for all adverse events (AEs) from day 1 to day 42 postvaccination and for serious AEs (SAEs) through day 182 postvaccination.

RESULTS

The ZV reduced the incidence of HZ (30 cases in vaccine group, 1.99/1000 person-years vs 99 cases in placebo group, 6.57/1000 person-years). Vaccine efficacy for preventing HZ was 69.8% (95% confidence interval, 54.1-80.6). AEs were reported by 72.8% of subjects in the ZV group and 41.5% in the placebo group, with the difference primarily due to higher rates of injection-site AEs and headache. The proportion of subjects reporting SAEs occurring within 42 days postvaccination (ZV, 0.6%; placebo, 0.5%) and 182 days postvaccination (ZV, 2.1%; placebo, 1.9%) was similar between groups.

CONCLUSIONS

In subjects aged 50-59 years, the ZV significantly reduced the incidence of HZ and was well tolerated.

CLINICAL TRIALS REGISTRATION

NCT00534248.

Cutaneous infections and infestations: new therapies

Directed and preventive therapies for cutaneous infectious disease and infestation continue to evolve, providing physicians with new options for care. Common infectious diseases (e.g., genital herpes, herpes zoster, and head lice) occur in the outpatient and inpatient setting. This review of the literature highlights new therapies, including those still in development, such as novel drugs and vaccines, all of which should help to decrease the frequency and severity of common infectious diseases of the skin and subcutaneous tissues.

A refresher on herpes zoster, current status on vaccination, and the role of the dermatologist

BACKGROUND

Herpes zoster (HZ) and postherpetic neuralgia (PHN) have a significant impact on quality of life. PHN is often chronic and difficult to treat. Dermatologists have always been involved in making the diagnosis of these conditions and, most recently, teaching the need for early antiviral therapy.

OBJECTIVE

With the introduction of a new vaccine, HZ and its difficult-to-treat complication PHN can be prevented or minimized. Preventive medicine is important and has been supported by dermatologists with sun safety programs. Patients receiving biologics are at increased risk of developing zoster.

CONCLUSION

Dermatologists should embrace zoster vaccination and recommend routine vaccination of immunocompetent individuals > age 60 years, as well as patients of any age who are starting immunosuppressants, including biologics. Given that individuals over age 50 years are at risk for PHN and studies have shown that the vaccine's immunogenicity and safety are maintained in individuals age 50 to 59 years, vaccination in this age group may be considered. Some dermatologists may consider vaccinating their own patients, but most will likely recommend that vaccination be performed by their patients' primary care physicians.

Treatment of skin and soft tissue infections in the elderly: A review

BACKGROUND

Skin and soft tissue infections (SSTIs) have become the second most common type of infection among persons residing in long-term care facilities.

OBJECTIVE

The purpose of this article was to review the latest information on SSTIs among the elderly, including age-related changes, challenges, and treatment strategies in the era of emerging bacterial resistance.

METHODS

Relevant information was identified through a search of MEDLINE (1970-April 2010), International Pharmaceutical Abstracts (1970-April 2010), and Google Scholar using the terms skin and soft tissue infection, skin and skin structure infection, cellulitis, treatment guidelines, and elderly. Additional publications were found by searching the reference lists of the identified articles. Trials published since 1970 were selected for this review if they prospectively evaluated mostly adults (≥18 years of age), included >50 patients, and reported diagnostic criteria as well as clinical outcomes in patients treated for simple or complicated SSTIs.

RESULTS

Fifty-eight of 664 identified studies were selected and included in this review. A search of the literature did not identify any prospective clinical trials that were conducted exclusively in the elderly. Information on the treatment of SSTIs in the elderly was based solely on clinical studies that were conducted in adults in general. As recommended by the Infectious Diseases Society of America (IDSA) 2008 update, SSTIs should be suspected in elderly patients who have skin lesions and present with a decline in functional status, with or without fever. Patients who present with symptoms of systemic toxicity should be hospitalized for further evaluation. Current challenges in the management of SSTIs include the rapid emergence of community-acquired, methicillin-resistant Staphylococcus aureus (CA-MRSA), the emergence of macrolide-resistant streptococci within the past decade, and the lack of a reliable algorithm to differentiate potentially life-threatening SSTIs that require aggressive interventions and prompt hospitalization from those that can be managed in an outpatient setting. S aureus was the most common cause of SSTIs, being isolated in 42.8% (5015/11,723) of wounds, followed by streptococci. Common SSTIs in the elderly such as shingles, diabetic foot infections, infected pressure ulcers, and scabies, and their treatment were also discussed. Based on reviews of published trials, treatment of simple SSTIs generally consisted of administration of agents with activity against S aureus and Streptococcus species such as a penicillinase-resistant β-lactam, a first-generation cephalosporin, or clindamycin. Broadening of the antimicrobial spectrum to include gram-negative and anaerobic organisms should be implemented for complicated SSTIs such as diabetic foot infections and infected pressure ulcers. Local rates of MRSA, CA-MRSA, and macrolide-resistant streptococci should be considered when selecting empiric therapy.

CONCLUSIONS

A search of the literature did not identify any prospective clinical trials on the treatment of SSTIs in the elderly; therefore, it is recommended to follow treatment based on the current IDSA guidelines. More research and publications are needed to establish proper selection of antimicrobial agents, treatment strategies, and duration of therapy of SSTIs in the elderly population.

Perspectives on vaccines against varicella-zoster virus infections

Primary infection with varicella-zoster virus (VZV) results in varicella which, in populations where immunization is not used, occurs mostly in children. Varicella is a generalized rash illness with systemic features such as fever and malaise. During varicella, VZV becomes latent in sensory ganglia of the individual, and in 70% it remains asymptomatic for their lifetime. The remaining 30% develop reactivation from latency, resulting in herpes zoster (HZ). HZ usually occurs in persons over the age of 50, and is manifested by a painful unilateral rash that usually lasts about 2 weeks and then may be followed by a chronic pain syndrome called post-herpetic neuralgia (PHN). VZV infections are notoriously more severe in immunocompromised hosts than in healthy individuals. Despite gaps in our understanding of the details of immunity to VZV, successful vaccines have been developed against both varicella and zoster.

Strategies to improve the effect of vaccination in the elderly: the vaccine producer's perspective

The weakened immune system of elderly people presents particular challenges in the development of vaccines and vaccination strategies for this population. There are well recognized changes in the function of antigen presenting cells (APCs), T cells and B cells in older people. Several strategies to improve vaccination in the elderly have been explored. The use of adjuvants (e.g. emulsions and Toll-like receptor [TLR] agonists) could trigger more potent activation of APCs. The addition of T helper epitopes to the vaccine antigens could enhance T-cell responses by acting as 'intrinsic' adjuvants. The use of interleukin (IL)-7 could improve the expansion of naïve T cells in the elderly, accompanied by a broadened T-cell repertoire. A further means of enhancing antigen presentation and subsequent T-cell activation would be to increase the vaccine dose and/or antigenic content. Vaccination schedules could also be adapted. In particular, vaccination at an earlier age may trigger naïve T cells and subsequent generation of memory cells more efficiently and these cells may be recalled more easily in later life. Vaccination against cytomegalovirus (CMV) early in life has also been proposed to avoid the 'CMV bias' of the immune response that is seen in the elderly population. Immunization routes other than by intramuscular or subcutaneous injection may be more efficient, by delivering antigen to sites enriched in APCs such as the epidermis and/or dermis. Finally, the use of polysaccharide-protein conjugates might enhance the level and functionality of antibodies directed against polysaccharides. These different possibilities, alone or in combination, could improve vaccine efficacy in elderly human populations.