Management of a major varicella zoster exposure in a pediatric oncology population

Management of the exposure of pediatric oncology patients to varicella zoster virus (VZV) is controversial. We report the exposure of 56 patients to a single child with chicken pox at a pediatric cancer housing facility and describe our strategic approach for their management. We reviewed the immune and clinical status of 56 children with cancer receiving ongoing treatment at Memorial Sloan Kettering Cancer Center (MSK) who, while living at a pediatric cancer housing facility, were exposed to the index patient. The management of patients exposed included: (1) determination of immune status, (2) availability of vaccination history or VZV disease prophylaxis, (3) exposure status and subsequent isolation during the period of incubation, and (4) VZV disease prophylaxis. In addition to the 56 patients exposed to the index case, eight children with cancer treated at other facilities and 11 healthy siblings living in the facility were exposed. Of the 56 MSK patients, 21 were classified as immunosuppressed and received varicella zoster immune globulin (human), intravenous standard immune globulin, or acyclovir based on serostatus and immune function. The cohort was followed for 4 weeks after the exposure and no secondary infections were diagnosed. We performed a risk assessment and created a management plan to control and prevent further exposure and development of disease. No secondary cases developed. This strategic approach could serve as a model for the management of VZV exposure for other pediatric oncology centers.

Prevention and Control of Nosocomial Varicella During the United States Varicella Vaccination Program Era

The United States varicella vaccination program has successfully reduced varicella incidence and hospitalizations by ≥90%, consequently reducing the risk of nosocomial exposures. However, patients and healthcare personnel (HCP) continue to introduce varicella zoster virus (VZV) into healthcare settings. Herpes zoster (HZ) is less contagious than varicella, but it can also result in exposures. Unrecognized varicella and HZ may lead to extensive contact investigations, control efforts, and HCP furloughs that result in significant disruption of healthcare activities as well as substantial costs. Robust occupational health and infection prevention programs that ensure healthcare personnel immunity and prompt recognition and isolation of patients with varicella or HZ will lower the risk of VZV transmission and reduce or eliminate the need to furlough exposed HCP and associated costs.

Communicability of varicella before rash onset: a literature review

Varicella poses an occupational risk and a nosocomial risk for susceptible healthcare personnel and patients, respectively. Patients with varicella are thought to be infectious from 1 to 2 days before rash onset until all lesions are crusted, typically 4–7 days after onset of rash. We searched Medline, Embase, Cochrane Library and CINAHL databases to assess evidence of varicella-zoster virus (VZV) transmission before varicella rash onset. Few articles (7) contributed epidemiologic evidence; no formal studies were found. Published articles reported infectiousness at variable intervals before rash onset, between <1 day to 4 days prior to rash, with 1–2 patients for each interval. Laboratory assessment of transmission before rash was also limited (10 articles). No culture-positive results were reported. VZV DNA was identified by PCR before rash onset in only one study however, PCR does not indicate infectivity of the virus. Based on available medical literature, VZV transmission before rash onset seems unlikely, although the possibility of pre-rash, respiratory transmission cannot be entirely ruled out.

Implementation of Hospital Policy for Healthcare Workers and Patients Exposed to Varicella-Zoster Virus

Varicella-zoster virus (VZV) causes a highly contagious and generally benign, self-limited disease. However, in high-risk populations including immunocompromised patients, pregnant women, and neonates, VZV infection can be associated with significant morbidity and mortality. Healthcare-associated transmission of VZV occurs among healthcare workers (HCWs) and patients by airborne transmission or by direct contact with the index case. To minimize the risk of transmission in healthcare settings, all VZV-susceptible HCWs should be encouraged strongly to be immunized with the varicella vaccine. For post-exposure management, active immunization (varicella vaccine), passive immunization (varicella-zoster immune globulin) and/or antiviral agents, and isolation could be used in specific situations. To prevent the transmission of VZV infection in the hospital settings, the development and implementation of hospital policies for appropriate infection control is also warranted. This article reviews the general information and healthcare-associated transmission of VZV and summarizes the recommendations for the pre- and post-exposure management of HCWs and patients, in hospital settings.

Varicella zoster virus transmission in youth during incarceration

Purpose - Facility-based Varicella zoster virus (VZV) transmission is reported in a Canadian youth offender correctional centre (YOCC). Transmission occurred from an immunocompetent youth offender (YO) with localized Herpes zoster to another immunocompetent single dose vaccinated YO, resulting in Varicella zoster (VZ) breakthrough disease. The purpose of this paper is to identify infection prevention and control (IPAC) measures utilized in this setting. Design/methodology/approach - A retrospective chart and immunization record review was conducted for two VZV cases and 27 exposed YO contacts in order to obtain demographic, clinical and immunization data. Descriptive data analysis was performed. Findings - All VZV cases and exposed contacts were male with an average age of 14.2 and 15.6 years for cases and contacts, respectively. Both cases shared the same living unit in the YOCC. There were 28 identified YO contacts, of whom 70 percent were single dose vaccinated with univalent vaccine, followed by 22 percent with a previous history of Varicella disease. All cases and contacts were born in Canada. No foreign-born populations were involved with this event. Infection control measures included additional precaution management, enhanced surveillance and environmental cleaning. As such, no hospitalizations or post-exposure immunizations were required. Originality/value - This report highlights the role that VZ breakthrough disease could play in fueling an outbreak in a high-risk environment without rapid recognition and implementation of preventative measures. It also underscores the importance of IPAC presence and public health immunization programs within correctional centers to avoid infectious disease threats.

Varicella in a Previously Immune Patient With Leukemia

Infection with varicella-zoster virus (VZV) in oncology patients can result in severe disease with an increased risk of morbidity and mortality [1, 2]. Among patients on cancer chemotherapy, only nonimmune persons are considered to be susceptible to varicella [1]. We present a case of varicella in a child with leukemia that occurred despite immunity as defined by 2 doses of varicella vaccine and documentation of positive VZV immunoglobulin G titer before initiation of chemotherapy.

Genotype analysis of ORF 62 identifies varicella-zoster virus infections caused by a vaccine strain in children

This study was performed to differentiate vaccine-type strains from wild-type strains and determine the genotype of varicella-zoster virus (VZV) in 51 Korean children. A sequencing analysis of ORF 62 identified two cases of herpes zoster caused by the vaccine-type virus, without a previous history of varicella, 22 months and 5 months after VZV vaccination. The wild-type strain was identified in the remaining children. A genotype analysis of ORF 22 amino acids revealed genotype J in all children except one. Genotype E was identified in an infant with varicella imported from Egypt.

Incidence and consequences of varicella in children treated for cancer in Guatemala

BACKGROUND

Varicella-zoster virus infection is associated with significant morbidity and mortality in immune-compromised children, despite treatment with antiviral agents. Universal varicella vaccine programs have significantly decreased this risk in many highincome countries, but in most low-income and middleincome countries, the burden of varicella in children treated for malignancy is poorly defined.

METHODS

We retrospectively reviewed records of children at the National Unit of Pediatric Oncology (UNOP) in Guatemala diagnosed with varicella between January 2009 and March 2013 in order to calculate incidence of varicella and evaluate morbidity, mortality, treatment interruption, and cost.

RESULTS

Fifty-nine cases of varicella were identified. Incidence was 23.4 cases per 1000 person-years (p-y). 66.1% of cases occurred in children with leukemia (median age 5.2 years; interquantile range 3.4-7 years) and 41.0% of these occurred during maintenance therapy. Source of exposure was identified for 14/59 (23.7%) children. Most were hospitalized (71.2%) and given intravenous acyclovir (64.4%). Eight (13.6%) children required critical care, and two (3.4%) died from disseminated varicella with multiorgan failure. Chemotherapy was delayed or omitted due to varicella in 50%. No significant differences in outcomes based on nutritional and immunologic status were detected. The minimum average cost of treatment per episode was 598.75 USD.

CONCLUSIONS

Varicella is a significant problem in children treated for cancer in Guatemala, where effective post-exposure prophylaxis is limited. In the absence of universal varicella vaccination, strategies to improve recognition of exposure and the future use of novel inactivated vaccines currently under investigation in clinical trials could mitigate this burden.

Clinical and economic impact of various strategies for varicella immunity screening and vaccination of health care personnel

BACKGROUND

Exposure to patients with varicella or herpes zoster causes considerable disruption to a health care facility's operations and has a significant health and economic impact. However, practices related to screening for immunity and immunization of health care personnel (HCP) for varicella vary widely.

METHODS

A decision tree model was built to evaluate the cost-effectiveness of 8 different strategies of screening and vaccinating HCP for varicella. The outcomes are presented as probability of acquiring varicella, economic impact of varicella per employee per year, and cost to prevent additional cases of varicella. Monte Carlo simulations and 1-way sensitivity analyses were performed to address the uncertainties inherent to the model. Alternative epidemiologic and technologic scenarios were also analyzed.

RESULTS

Performing a clinical screening followed by serologic testing of HCP with negative history diminished the cost impact of varicella by >99% compared with not having a program. Vaccinating HCP with negative screen cost approximately $50,000 per case of varicella prevented at the current level of U.S. population immunity, but was projected to be cost-saving at 92% or lower immunity prevalence. Improving vaccine acceptance rates and using highly sensitive assays also optimize cost-effectiveness.

CONCLUSION

Strategies relying on screening and vaccinating HCP for varicella on employment were shown to be cost-effective for health care facilities and are consistent with current national guidelines for varicella prevention.

Infection Prevention and Control Guidance for Ronald McDonald Houses: A Needs Assessment

We surveyed Ronald McDonald Houses (RMHs) to assess infection prevention and control (IPC) practices. A diverse patient population is served by RMH. Most sites have locally written IPC guidelines, and consultation resources vary, increasing the potential for inconsistent IPC practices. RMH would benefit from a standardized IPC guideline.

Infect Control Hosp Epidemiol 2012;33(3):299-301

Infection Prevention and Control in Residential Facilities for Pediatric Patients and Their Families

The Society for Healthcare Epidemiology of America (SHEA) guideline “Infection Prevention and Control in Residential Facilities for Pediatric Patients and Their Families” is the first infection prevention and control (IPC) guideline to address preventing transmission of infectious agents in “home away from home” residential settings, of which the Ronald McDonald Houses (RMHs) serve as a prototype. These types of facilities provide support services, including overnight lodging, for ill and injured children and their families. Food preparation occurs in common areas, and cleaning of rooms or apartments is performed by the occupants during their stay and before departure. Pediatric patients are frequent guests of the family-centered facilities while receiving or recovering from specialized medical therapy. Examples of high-risk populations served in these facilities include families of patients with cancer, recipients of stem cell or solid organ transplants, surgical and/or very-low-birthweight infants who receive care in neonatal intensive care units (NICUs), those with cystic fibrosis, and women with high-risk pregnancies awaiting delivery in a nearby medical center. Such facilities are located worldwide and vary in their physical structure and the predominant population served.

Varicella seroprevalence among health care workers in Korea: validity of self-reported history and cost-effectiveness of prevaccination screening

BACKGROUND

The validity of self-reported varicella history and cost-effectiveness of a prevaccination screening strategy have not been examined among health care workers (HCWs) living in Korea.

METHODS

We investigated varicella-zoster virus immunity of all HCWs in high-risk departments. To determine the history of varicella, all applicants completed a standardized questionnaire at the time of blood sampling for serologic testing.

RESULTS

Of the 550 HCWs, 526 (96%) were varicella seropositive. Although self-reported history was highly predictive of seropositivity (≥96%) among all age groups, the negative predictive value was extremely low (4%-5%) among all age groups. The prevaccination screening strategy was cheaper than vaccination without antibody screening if the varicella seroprevalence was >28%.

CONCLUSION

Seroprevalence was high (≥95%) among HCWs born in Korea before 1988. The self-reported varicella history did not accurately predict immunity, especially for individuals who have negative or uncertain varicella history. Given the high seroprevalence of varicella in Korean HCWs, serologic screening before vaccination was more cost-effective than universal vaccination.

Healthcare providers as sources of vaccine-preventable diseases

Vaccine-preventable infectious diseases may be introduced into the healthcare setting and pose a serious risk to vulnerable populations including immunocompromised patients. Healthcare providers (HCPs) are exposed to these pathogens through their daily tasks and may serve as a reservoir for ongoing disease transmission in the healthcare setting. The primary method of protection from work-related infection risk is vaccination that protects not only an individual HCP from disease, but also subsequent patients in contact with that HCP. Individual HCPs and healthcare institutions must balance the ethical and professional responsibility to protect their patients from nosocomial transmission of preventable infections with HCP autonomy. This article reviews known cases of HCP-to-patient transmission of the most common vaccine-preventable infections encountered in the healthcare setting including hepatitis B virus, influenza virus, Bordetella pertussis, varicella-zoster virus, measles, mumps and rubella virus. The impact of HCP vaccination on patient care and current recommendations for HCP vaccination against vaccine-preventable infectious diseases are also reviewed.

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.

How to manage vaccinations in children with cancer

The optimal use of routine childhood immunizations in children with malignancy is still a matter of debate. Despite their higher risk of contracting vaccine preventable diseases and of suffering important complications, there is little understanding of the magnitude of the possible benefit of administering active immunization in this population due to a paucity of clinical trial data. Our review focuses on the management of children with cancer and offers some suggestions regarding their vaccination schedules.

Preventing varicella in children with malignancies: what is the evidence?

PURPOSE OF REVIEW

The prevention of varicella in children with cancer is generally agreed to be an important goal, because of their elevated risk of varicella zoster virus (VZV)-associated morbidity and mortality. However, there is a lack of consensus on the best means of achieving this. Here, we review the existing evidence in relation to postexposure prophylaxis against varicella in this group and summarize data regarding the role of active vaccination.

RECENT FINDINGS

Death from varicella during treatment for cancer is now rare, but VZV disease and its prevention remain significant problems in paediatric oncology practice. Measures to reduce VZV exposure amongst seronegative individuals are often neglected. When exposure is known to have occurred, early administration of varicella zoster immune globulin (VZIG) is generally protective against severe and complicated varicella. However, many centres in the UK and Japan use an oral antiviral agent, aciclovir, in place of VZIG. Published evidence for the efficacy of aciclovir as postexposure prophylaxis (PEP) relates mostly to healthy children, with no controlled studies in the immunocompromised.

SUMMARY

Good evidence already supports the administration of varicella vaccine to healthy susceptible family contacts of children with malignancy, but not to patients themselves. Further data are urgently needed to inform the choice of PEP against VZV in the immunocompromised.

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.