The varicella vaccine. Clinical trials in immunocompromised individuals

Pilot Analyses of Interferon Subtype Expression Profiles in Patients with Herpes Zoster or Postherpetic Neuralgia

Postherpetic neuralgia (PHN) is a painful neuropathic complication resulting from herpes zoster (HZ). The pain manifests in peripheral nerves infected by herpesviruses, mostly from reactivation of latent varicella zoster virus. Mechanistic descriptions suggest that PHN develops because of disrupted immune system signaling and inflammation or peripheral nerve damage; however, the pathophysiology is not clear. It is difficult to predict/prevent PHN manifestations of HZ patients due to the lack of accurate diagnostics. In this study, sera from healthy controls, HZ patients, and PHN patients were subjected to an interferon (IFN) expression profile (IEP) study. The corresponding cDNAs were analyzed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) using primer pairs against a panel of 21 different IFN subtypes. The results showed that distinct IEPs were observed among HZ and PHN cohorts in comparison to the healthy controls. Together, this pilot study suggested that the IEP study may be used as a molecular tool for diagnosis of PHN and assist in designing new PHN therapeutic protocols.

Transmission of Vaccine-Strain Varicella-Zoster Virus: A Systematic Review

CONTEXT

Live vaccines usually provide robust immunity but can transmit the vaccine virus.

OBJECTIVE

To assess the characteristics of secondary transmission of the vaccine-strain varicella-zoster virus (Oka strain; vOka) on the basis of the published experience with use of live varicella and zoster vaccines.

DATA SOURCES

Systematic review of Medline, Embase, the Cochrane Library, Cumulative Index to Nursing and Allied Health Literature, and Scopus databases for articles published through 2018.

STUDY SELECTION

Articles that reported original data on vOka transmission from persons who received vaccines containing the live attenuated varicella-zoster virus.

DATA EXTRACTION

We abstracted data to describe vOka transmission by index patient's immune status, type (varicella or herpes zoster) and severity of illness, and whether transmission was laboratory confirmed.

RESULTS

Twenty articles were included. We identified 13 patients with vOka varicella after transmission from 11 immunocompetent varicella vaccine recipients. In all instances, the vaccine recipient had a rash: 6 varicella-like and 5 herpes zoster. Transmission occurred mostly to household contacts. One additional case was not considered direct transmission from a vaccine recipient, but the mechanism was uncertain. Transmission from vaccinated immunocompromised children also occurred only if the vaccine recipient developed a rash postvaccination. Secondary cases of varicella caused by vOka were mild.

LIMITATIONS

It is likely that other vOka transmission cases remain unpublished.

CONCLUSIONS

Healthy, vaccinated persons have minimal risk for transmitting vOka to contacts and only if a rash is present. Our findings support the existing recommendations for routine varicella vaccination and the guidance that persons with vaccine-related rash avoid contact with susceptible persons at high risk for severe varicella complications.

Varicella-zoster-virus vaccination in immunosuppressed children with rheumatic diseases using a pre-vaccination check list

BACKGROUND

The goal of this study was to apply the varicella zoster virus (VZV) vaccine to patients with pediatric rheumatic diseases (PRD) at risk for severe chickenpox, without interrupting their current immunosuppression, including biological agents, using an immunological-based pre-vaccination checklist to assure safety. A pre-vaccination checklist was implemented to ensure adequate immune competence prior to immunization.

METHODS

This prospective study included seronegative patients (VZV-IgG ≤200 mIU/ml) and patients who had previously received only a single dose of VZV vaccine. All vaccinees demonstrated clinically inactive PRD. Patients were categorized according to their actual treatment in low-intensity IS (LIIS) and high-intensity IS (HIIS) including biological therapy. The pre-vaccination checklist defined thresholds for the following basic laboratory tests: white blood cell count ≥3000/mm³, lymphocytes ≥1200/mm³, serum IgG ≥500 mg/dl, IgM ≥20 mg/dl, tetanus toxoid antibody ≥0.1 IU/ml. In case of HIIS additional specifications included a CD4+ lymphocyte count ≥200/mm³ and a positive T-cell function (via analyzable positive control of a standard tuberculosis interferon-gamma-release-assay (TB-IGRA) indicating mitogen-induced T cell proliferation). Patients who met the criteria of the pre-vaccination checklist received the first and/or second VZV vaccination. Immunologic response and side effects were monitored.

RESULTS

Twenty-three patients were recruited of whom nine had already received one VZV immunization before initiating IS. All patients met the pre-vaccination checklist criteria despite ongoing IS. There was no overall difference in VZV-IgG levels when comparing the LIIS (n=9) and HIIS (n=14) groups. In total, 21 patients (91%) showed a positive vaccination response, after the first immunization the median VZV-IgG across all patients was 224 (59-1219) mIU/ml (median (range)), after booster immunization it increased to 882 (30-4685) mIU/ml. Two patients in the HIIS group failed to raise positive VZV-IgG, despite booster immunization. All nine patients receiving only the second immunization on IS reached high titers of VZV-IgG >500 mIU/ml (1117 (513-4685) mIU/ml). There were no cases of rash or other vaccine-induced varicella disease symptoms and no evidence of PRD flare.

CONCLUSIONS

VZV vaccination is safe and largely immunogenic in children with ongoing IS fulfilling an immunological based pre-vaccination checklist. This new approach is based on immunologic function rather than on type of medications.

TRIAL REGISTRATION NUMBER

ISRCRTN trial registration number 21654693 , date of registration February 12, 2018, retrospectively registered.

Varicella Virus Vaccination in the United States

Varicella zoster virus (VZV) is the cause of chickenpox (varicella) and shingles (zoster), and was once responsible for over 4 million infections in the United States annually. The development of a live attenuated VZV vaccine was initially viewed with extreme skepticism. Nonetheless, a VZV vaccine was developed in the 1970s by Takahashi and his colleagues in Japan and was eventually licensed in the US. It is now known to be one of the safest and most effective vaccines available and is administered worldwide. Here are described important factors that contributed to the successful research and licensure of the highly successful VZV vaccine.

Varicella in pediatric oncology patients in the post-vaccine era-Analysis of routine hospital data from Bavaria (Germany), 2005-2011

Varicella in oncology patients can result in serious complications. We analyzed trends in hospitalization rates and characteristics of pediatric oncology and non-oncology patients hospitalized with varicella during the first 7 years after introduction of routine varicella vaccination. Our data included children <17 years of age with an International Classification of Diseases and Related Health Problems, 10th Revision (ICD-10) main or secondary discharge diagnosis of varicella identified by annual database queries in 22-29 pediatric hospitals in Bavaria (Germany) in 2005-2011. Of a total of 1,245 varicella-associated hospitalizations, 42 children (median age 4 years, interquartile range 3-5) had an underlying malignancy (67% with acute lymphoblastic leukemia). Overall, additional diagnoses potentially associated with varicella were reported less often in oncology than in non-oncology varicella patients (62% vs. 77%, p = 0.041), suggesting earlier hospitalization of high-risk patients. Acute hematological diagnoses (29% vs. 3%, p < 0.001) and coinfections (invasive 12% vs. 2%, p = 0.001; noninvasive 19% vs. 8%, p = 0.019) were more frequent, whereas neurological (5% vs. 19%, p = 0.023) and upper respiratory tract diagnoses (2% vs. 16%, p = 0.014) were less frequent in oncology compared to non-oncology varicella patients. Oncology varicella patients showed a longer hospital stay (median 5 vs. 3 days, p < 0.001). Hospitalization rates in non-oncology varicella patients declined constantly since 2006, from 114.8 (2006) to 30.5 (2011) per 1,000 pediatric beds. The rates of varicella-associated hospitalizations in oncology patients indicated an overall decreasing trend (3.8, 1.9, 4.6, 3.5, 0.4, 2.1 and 0.6 cases per 1,000 pediatric beds in 2005-2011). Thus, pediatric oncology patients potentially profit from herd protection effects, resulting from increasing vaccine coverage in the general population.

Chicken pox infection in patients undergoing chemotherapy: A retrospective analysis from a tertiary care center in India

There is paucity of data on the incidence, severity and management of chicken pox in patients receiving active chemotherapy for cancer. From October 2010 to October 2011, patients were included in this study if they developed a chicken pox infection during their chemotherapy. The details of patients' cancer diagnosis and treatment along with clinical and epidemiological data of the chicken pox infections were assessed from a prospectively maintained database. Twenty-four patients had a chicken pox infection while receiving chemotherapy and/or radiotherapy. The median age of the patients was 21 years, and two-thirds of the patients had solid tumor malignancies. Overall, eight (33%) patients had complications, six (25%) patients had febrile neutropenia, four (17%) had diarrhea/mucositis, and four (17%) had pneumonia. The median time for recovery of the infection and complications in the patients was 9.5 days (5-29 days), whereas for neutropenic patients, it was 6.5 days (3-14 days). The median time for recovery from chicken pox infections in neutropenic patients was 10 days (5-21 days), compared with 8.5 days (0-29 days) in non-neutropenic patients (P=0.84). The median time for recovery from infections was 8.5 days in patients with comorbidities (N=4), which was the same for patients with no comorbidities. The clinical presentation and complication rates of chicken pox in cancer patients, who were on active chemotherapy, are similar to the normal population. The recovery from a varicella infection and complications may be delayed in patients with neutropenia. The varicella infection causes a therapy delay in 70% of patients. Aggressive antiviral therapy, supportive care and isolation of the index cases remain the backbone of treatment.

Infection Prevention and Control Issues After Solid Organ Transplantation

Infections are an important cause of morbidity and mortality in solid organ transplant recipients. Consequently, infection prevention is an essential component of any organ transplant program. Given their frequent and often prolonged contact with the healthcare system, solid organ transplant recipients are at high risk for healthcare-associated infections, including those caused by antibiotic-resistant organisms. In this chapter we review several different healthcare-associated infections of importance to transplant recipients, including those caused by bacterial, viral, and fungal organisms. We also describe infection prevention and control strategies applicable to this patient population. These practices focus on clinical interventions and environmental controls designed to prevent the spread of potentially pathogenic organisms in the healthcare setting. We also describe post-exposure interventions applicable to solid organ transplant recipients exposed to potential pathogens in order to reduce their risk of subsequent infection.

2013 IDSA clinical practice guideline for vaccination of the immunocompromised host

An international panel of experts prepared an evidenced-based guideline for vaccination of immunocompromised adults and children. These guidelines are intended for use by primary care and subspecialty providers who care for immunocompromised patients. Evidence was often limited. Areas that warrant future investigation are highlighted.

Immunization in special populations

In summary, immunizations in special populations require understanding the underlying disease and how it might affect the immune system's ability to mount an antibody response to vaccines or predispose certain patient populations to developing certain serious infections. There is still a great need for research on the optimal timing of vaccines after transplants, how to assess protection and development of a protective antibody response after immunization, and whether certain groups (eg, HIV) need to be revaccinated after a certain amount of time if their antibody levels decline. In addition, there are limited data on efficacy of the newer vaccines in these special patient populations, which also requires further investigation.

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.

Vaccinations in children with cancer

Children with cancer may be immunocompromised as a result of their primary underlying disease and/or the use of prolonged and intensive chemotherapy administered with or without irradiation. The damage to the immune system varies with the age of the patient, the type of cancer, and the intensity of the chemotherapy used to treat it. This review analyses the data regarding the immunogenicity, efficacy, safety and tolerability of the vaccines usually recommended in the first years of life in order to help pediatricians choose the best immunisation programme against vaccine-preventable disease in children with cancer receiving standard-dose chemotherapy. Areas for future research are highlighted because new data are required to be able to draw up evidence-based recommendations that will ensure adequate protection against infectious diseases in such high-risk children.

Vaccination guidelines for children with cancer and hematopoietic stem cell transplantation living in resource-poor countries

There is no consensus on the immunization guidelines for immunocompromised children. Some recommendations are, however, available for children living in developed countries. The spectrum of infectious diseases is different in resource-poor countries. Vaccinations against some of these infections are not a part of the immunization schedule for children living in developed countries. We have tried to include vaccinations against diseases, which are still prevalent and a major cause of morbidity and mortality in resource-poor countries. In these guidelines, the focus has been on the vaccine-preventable diseases prevalent in Pakistan but the same can be applied to other resource-poor countries.

Varicella vaccination of immunocompromised children

BACKGROUND

Exposure of immunocompromised children to varicella often requires postexposure prophylaxis. Exposures requiring this management are often not recognized. Varicella can be a severe disease when it occurs in immunocompromised children, in spite of antiviral therapy. Varicella exposure and varicella in these children can also disrupt scheduled therapy for their underlying illness. Both postexposure prophylaxis and treatment of varicella are likely to be expensive and use significant medical resources. Numerous trials have been undertaken to vaccinate children who are immunocompromised by a variety of conditions and therapies that depress their immune function.

METHODS

Clinical trials of varicella vaccine administration to immunocompromised children that were reported since 1975 were identified in the Ovid medical database. Reports were selected for analysis and discussion on the basis of their completeness and the utility of their conclusions.

RESULTS

Vaccination before immune compromise is discussed as a strategy for some settings. The obstacles, potential opportunities, and success in varicella vaccination for immunocompromised children are separately analyzed for (1) children with leukemia and other malignancies, (2) human immunodeficiency virus-infected children, and (3) children with hematopoietic stem cell or solid-organ transplantation.

CONCLUSIONS

Vaccination before immune compromise is often successful, and the vaccine-induced response is usually partially or fully protective. In many treatment settings, it is possible to safely vaccinate once the level of immune suppression has been reduced. Targets for future research are outlined. A consensus conference should be undertaken to develop guidelines for the use of varicella vaccine in immunocompromised children.

Molecular analysis of the Oka vaccine strain of varicella-zoster virus

Live attenuated Oka vaccine was subjected to molecular analysis, with the long-term goal of identifying genes in the vaccine strain responsible for its attenuation. Complete genomic sequences for both the Oka parent virus and the Oka vaccine virus were determined and compared. There were differences in only 42 bases between the 2 viruses. More than one-third (15/42) of the nucleotide substitutions in V-Oka were found in open reading frame (ORF) 62. These differences were also observed when sequences of Japanese low-passage clinical isolates of varicella-zoster virus (VZV) were compared with the Oka vaccine strain. The ORF62 gene encodes an immediate early (IE) protein, IE62, that is the major transactivator of VZV and, as such, is critical to initiating the VZV gene expression cascade. Several insertions and deletions were also observed in comparing the 2 sequences, largely in the internal tandem repeat units. Functional differences between the 2 types of Oka virus were also examined. Oka vaccine was found to consist of a mixture of different subpopulations, and the parental Oka virus replicates more efficiently than does the vaccine strain. Development of a bacterial artificial chromosome for VZV expression should lead to the discovery of additional differences in wild and vaccine types and, thus, enhance our understanding of the genetic basis for attenuation of the Oka vaccine strain.

Varicella vaccination in Europe: are we ready for a universal childhood programme?

Safe and effective vaccines against varicella zoster virus (VZV), the aetiological agent of varicella and shingles, have been available in Europe for the last 5-10 years. The USA has had a universal childhood vaccination policy since 1995 and this has resulted in a dramatic decrease in the incidence, morbidity and mortality related to varicella. The economic and medical burden of VZV has led to discussions regarding both the desirability and feasibility of a similar routine immunisation policy for all European children. This article examines the epidemiology of varicella in Europe and how the data emerging from the USA can be used to achieve adequate prevention of the disease. It looks into the current evidence of the health economic evaluation of universal varicella vaccination and explores the concerns surrounding such a policy, including the postulated impact on the incidence of zoster. In conclusion, the Society of Independent European Vaccination Experts (SIEVE) recommends that the immunisation of susceptible adolescents needs to be urgently implemented, in addition to the current recommendations targeting high-risk patients, their close contacts with a negative history of varicella and seronegative health-care workers. A universal policy, optimally incorporating a two-dose schedule, will be needed to finally reduce the burden of disease of varicella from a societal point of view. The SIEVE recommends the implementation of such a policy as soon as financially and practically possible.

Severe varicella caused by varicella-vaccine strain in a child with significant T-cell dysfunction

In March 1995, the US Food and Drug Administration approved a live attenuated varicella vaccine for use in healthy children 12 months to 12 years old. We report here an 18-month-old girl with cell-mediated immunodeficiency who developed a severe vaccine-associated rash and clinical evidence of vaccine-associated pneumonia 1 month after inadvertent receipt of varicella vaccine.

Preventing varicella-zoster disease

Varicella-zoster virus (VZV), the cause of chickenpox and shingles, is a pathogen in retreat following the introduction of mass vaccination in the United States in 1995. The live attenuated Oka vaccine, which is safe and immunogenic, gives good protection against both varicella and zoster in the short to medium term. It has undoubtedly been highly effective to date in reducing all forms of varicella, especially severe disease. However, the huge pool of latent wild-type virus in the population represents a continuing threat. Both the biology and the epidemiology of VZV disease suggest that new vaccination strategies will be required over time.

A review of the varicella vaccine in immunocompromised individuals

BACKGROUND

Individuals with underlying cell-mediated immunodeficiency disorders are at high risk of developing severe, life-threatening illness associated with varicella-zoster virus infection. A live-attenuated varicella vaccine is recommended for routine childhood immunisation in some countries. In healthy children, the vaccine is efficacious and safe but because immunocompromised individuals may be unable to limit replication of live-attenuated vaccine viruses, the varicella vaccine is not recommended for them and there are few exceptions.

OBJECTIVES

The purpose of this paper is to review the published studies addressing the use of the varicella vaccine in people with cell-mediated immunodeficiency disorders.

METHODS

A computerised search on the PubMed database was used to collect the relevant papers published up to March 2003.

RESULTS

The varicella vaccine has been extensively studied in susceptible children with acute lymphoblastic leukaemia in remission, but studies involving individuals with other immunodeficiency disorders are scarce. Some of the current recommendations are based on very few and small studies with short follow-up. Immunocompromised individuals should be given the varicella vaccine only with complete knowledge of their clinical and immunological conditions and after considering the risks of natural infection and vaccination.

Infectious disease capsules: a pox on your house

A 31-year-old, previously healthy white man presented to the emergency department with complaints of malaise, fevers, shortness of breath, a non-productive cough, and a "rash." His physical exam revealed a temperature of 100.2F, a pulse of 129 bpm, respiratory rate of 14 BPM, and blood pressure of 140/74 mm Hg. He was alert, oriented, and in no distress. His oropharynx was dry, his neck was supple, and cervical lymphadenopathy was absent. He had tachycardia, bilateral wheezes, and rhonchi with prolonged expirations. There was a diffuse vesicular eruption enveloping his entire body with involvement sparing his palms and soles (Figures 1 and 2). Laboratory values showed a hemoglobin of 16.0 g/dL and a white blood cell count of 7100 cells/pL, with 39%neutrophils, 23% bands, and 35% lymphocytes. His platelet count was mildly decreased to 86,000 x 103/pL. Chest radiograph revealed bilateral diffuse interstitial infiltrates. A diagnosis of acute varicella-zoster virus pneumonia (varicella pneumonia) was made, and the patient was started on IV acyclovir (10 mg/kg every 8 hours). Upon further questioning, the patient stated that his daughter had been diagnosed with "chickenpox" 7 days ago. The patient had numerous exposures to chickenpox in the past but had never developed clinical expressions of varicella. He was not at risk for HIV infection, not having multiple sexual partners, IV drug abuse, or blood transfusions. During the 1 day of in-hospitalization, his fever abated and the pulmonary signs diminished. Following discharge, IV acyclovir was replaced by valacyclovir to complete a 7-day course of therapy.

Routine childhood immunizations

The immunizations recommended in the 2001 Childhood Immunization Schedule are safe and effective. Newly approved vaccines, like the pneumococcal conjugate vaccine, hold the promise of eliminating or dramatically reducing persistent causes of childhood morbidity and mortality in the United States.

[Varicella vaccine]

Varicella vaccine has been extensively studied in Japan, the United States and Canada since 1974. Its efficacy in healthy children is good, on the order of 94%. It also has a good efficacy in immunocompromised children, such as children treated for acute leukemia or malignant tumors. However, the vaccine has to be administrated during a 2-3 week transient suppression of chemotherapy. In the USA, varicella vaccination is recommended for receptive adults who are particularly exposed to varicella, such as health professionals working with immunocompromised patients. Benefits and cost analysis of a generalized varicella vaccination in children has shown that it would be beneficial due to the cost of parents' work leave during the children's illness.

[Recommended vaccines and immunoglobulins for immunocompromised patients]

A revision of the literature was made as to the recommendations given for the use of vaccines and immune globulins in persons who presented total or partial immunodeficiency, mainly related to the nineties. The analysis of 75 references led to the following principal conclusions: the vaccines containing living agents are generally inappropriate for persons who present conditions which determine serious immunodeficiency; the vaccines which contain dead agents or only antigenic fractions, despite their being less immunogenic and conferring lower rates of protection to severely immunocompromised persons as compared to normal persons, are safe and should be administered to them. Immunocompromised patients should receive immune globulins for the same indications and in the same doses as immunocompetent persons, with the exception of immune globulin to prevent measles, as recommended in a dosage of 0.5 mL/Kg for immunodeficients (15 mL, maximum).

Frontiers of occupational health. New vaccines, new prophylactic regimens, and management of the HIV-infected worker

New prophylactic or treatment options are available for a number of infectious diseases that may be transmitted in the health care setting. Infectious diseases that can now be prevented by vaccination of the employee include hepatitis A, pertussis, hepatitis B, and primary varicella. New prophylactic or treatment regimens are available for Neisseria meningitidis, Streptococcus pyogenes, and Bordetella pertussis; treatment of multidrug-resistant tuberculosis is also discussed. Finally, management of the HIV-infected health care worker is reviewed.