Transmission Of Varicella-zoster Virus Research Articles

Transmission of varicella zoster virus in the presence of masking.

Transmission of varicella zoster virus in the presence of masking.

Varicella Seroprevalence among Healthcare Workers: A Pilot Study from a Tertiary Care Centre in Northern India

Introduction: Susceptible Healthcare Workers (HCWs) lacking immunity to Varicella Zoster Virus (VZV) can get infected and spread the infection to their patients. Effective screening can help in early vaccination to limit nosocomial transmission of VZV. Aim: To assess the seroprevalence of VZV among HCWs. Materials and Methods: This was a hospital-based pilot study where serum samples were collected from 201 HCWs working in different departments of the Government Medical College, Srinagar, Jammu and Kashmir, India and its eight associated hospitals over a period from January 2021 to February 2021, after obtaining their consent to participate in the study. Samples were tested for VZV Immunoglobulin G (IgG) antibodies using the Enzyme Linked Immuno Sorbent Assay (ELISA) method (NovaLisaVZVIgG, ELISA Kit). Variables including age, sex, professional category, history of varicella infection, and VZV vaccination were collected in a proforma. Statistical analysis was done using Open Epi version 3.01. Results: The overall prevalence of antibodies to varicella was 150/196 (76.53%). HCWs had equivocal results in 4 (2.04%) cases. An age-related increase in seroprevalence was observed. Only 6/196 (3.06%) participants were vaccinated against VZV, and 38/196 (19.39%) participants had a history of VZV infection in the past. Conclusion: The present study found a significant proportion of HCWs susceptible to VZV, making them potentially at risk of acquiring and transmitting the infection. This reinforces the need for screening HCWs against VZV and vaccinating them whenever necessary to protect the patients.

Vaccination against Varicella Zoster Virus Infection in Less Developed Regions of Guangdong, China: A Cross-Sectional Serosurveillance Study.

Vaccination is the key to prevent varicella zoster virus (VZV) infection in children. Voluntary and self-funded strategies have led to variable vaccination rates against VZV in China. For low-income populations, in particular, the effects of VZV vaccination have been insufficiently estimated. Community-based serosurveillance was conducted in two less developed regions, Zhanjiang and Heyuan, of Guangdong, China. Anti-VZV IgG antibodies in serum were detected by ELISA. The vaccination data were derived from the Guangdong Immune Planning Information System. A total of 4221 participants were involved, of which 3377 were from three counties of Zhanjiang and the other 844 were from one county of Heyuan, Guangdong, China. The total VZV IgG seropositivity rate in vaccinated individuals was 34.30% and 42.76%, while it was 89.61% and 91.62% in non-vaccinated populations of Zhanjiang and Heyuan, respectively. The seropositivity rate increased gradually with age, reaching ~90% in the >20- to 30-year-old group. The VarV vaccination rates of children aged 1-14 years were 60.47% for one dose and 6.20% for two doses in Zhanjiang, and 52.24% for one dose and 4.48% for two doses in Heyuan. Compared with the non-vaccinated group (31.19%) and one-dose group (35.47%), the positivity rate of anti-VZV IgG antibodies was significantly higher in the two-dose group (67.86%). Before the VarV policy was reformed, the anti-VZV IgG positivity rate was 27.85% in the one-dose-vaccinated participants, which increased to 30.43% after October 2017. The high seroprevalence in participants was due to infection of VZV in Zhanjiang and Heyuan, not vaccination against VZV. Children aged 0-5 years are still vulnerable to varicella, so a two-dose vaccination program should be implemented to prevent onward transmission of VZV.

Zoster on the brain: Clinical characteristics of patients PCR positive for varicella-zoster virus in cerebrospinal fluid and implications for transmission base

Background: Transmission-based precautions against varicella-zoster virus (VZV) in healthcare settings are determined by the extent of rash (localized vs disseminated) and the immune status of the host. At our facility, immunocompetent patients with localized disease are placed in standard precautions whereas patients with disseminated disease and/or immunocompromised status are placed in airborne and contact isolation. The use of molecular diagnostics has increased recently, and patients can have a PCR positive for VZV in cerebral spinal fluid (CSF) without evidence of pneumonia or disseminated rash. These patients are classified as disseminated disease, but it is unlikely that they are spreading VZV via respiratory aerosols in the absence of other symptoms. Infection prevention guidance is limited in this situation, and these patients may be in unneeded isolation, with the potential for adverse patient effects and overutilizing PPE resources. We have described the clinical characteristics of patients with a PCR positive for VZV in CSF, and we evaluated the risk for transmitting VZV via airborne aerosols. Methods: A retrospective, single-center chart review was performed on all patients admitted with a PCR positive for VZV in CSF between July 2017 and November 2021. Chart review was performed to gather data regarding clinical presentation, patient characteristics, and risk factors. Results: In total, 38 patients were identified who had a PCR positive for VZV in CSF; 22 (57.9%) were male and 16 (42.1%) were female. The median age was 47 years (IQR, 38–69). Also, 15 patients (39.5%) were immunocompromised. Moreover, 26 patients (68.4%) had a rash; 19 (50%) had localized rash; and 7 (18.4%) had disseminated rash involving ≥3 dermatomes. However, 12 patients (31.5%) had neither rash nor pneumonia. Furthermore, 5 patients (13.1%) had PCR positive for VZV in CSF and developed rash within the following 2–7 days (2 with disseminated rash). In addition, 6 patients (15.8%) had pneumonia. Of the 6 patients with pneumonia, 4 (10.5%) were immunocompromised and 3 (7.9%) were above 65-year-old. 32 patients (84.2%) were kept in airborne and contact precautions. 1 (2.6%) patient had a documented record of at least 1 dose of Shingrix vaccine. Conclusions: Most patients with a PCR test positive for VZV in the CSF were not immunocompromised and did not have evidence of disseminated rash or pneumonia. The risk of airborne transmission of VZV via small aerosols appears to be low in patients with a PCR test positive for VZV in the CSF without evidence of disseminated rash or pneumonia. Airborne isolation may not be required for many of these patients.Funding: NoneDisclosures: None

Still a hospital hazard: Varicella-Zoster virus infection in a health-care worker after exposure to Herpes Zoster

Varicella-Zoster Virus (VZV), a highly contagious herpesvirus, remains a hospital hazard and nosocomial transmission of VZV, despite vaccine availability, is well documented. Although World Health Organization (WHO) recommends immunization for all health-care providers, cases of in-hospital VZV transmission are still reported and summarized here, indicating the existence of susceptible individuals. Here in we present a case of a health-care worker, infected by a patient with disseminated herpes zoster and discuss aspects that generally may contribute to this event like the inadequacy of hospital infection control unit interventions, the risk of reinfection despite immunity, the complacency of employees concerning their immunity status to VZV and unfortunately the anti-vaccination movement. Adherence to published recommendations for reduction of serosusceptible hosts is of primary importance, especially in the era of increased immunocompromised population.

Seroprevalence survey for Varicella among healthcare workers and medical students in Italy

ABSTRACT Varicella is a potentially serious infectious disease caused by Varicella-Zoster Virus (VZV). In Italy childhood varicella vaccine have gradually introduced into national immunization program since 2003 and from 2017 a two-doses schedule has been stated nationally for all newborns and has become compulsory for school attendance. VZV exposures among healthcare workers (HCWs) and patients can be really dangerous and expensive. According to Centers of Disease Control and Italian national immunization plan health care, institutions should verify that all HCWs have clear evidence of immunity to VZV and should ensure that susceptible subjects will receive 2 doses of VZV vaccine. Currently, the vaccination of HCWs is not compulsory in Italy and the risk of varicella infection among these subjects is not well known. We evaluated the clinical records of 840 HCWs (256 male and 584 female) who underwent the annual occupational screening, from 1st January to 31st August 2018. HCWs were divided into three subgroups according to their age: 18–30, 31–40, and over 40 years old. We compared the mean values of IgG-specific antibodies between the age group through analysis of variance (ANOVA). A total of 784 (93.33%) HCWs were protected for VZV IgG antibodies level. There wasn’t a significant difference between male and female while was found between age group (P < 0.001). Protection levels for varicella are inadequate among HCWs. Despite the epidemiology of varicella in general population has changed with the implementation of the childhood varicella vaccination program transmission of VZV in hospitals is still a serious problem, so it is necessary to increase prevention activities in these settings, including vaccination.

Descriptive epidemiology of varicella based on national surveillance data before and after the introduction of routine varicella vaccination with two doses in Japan, 2000–2017

Routine childhood immunization using two doses of the varicella vaccine was introduced in Japan in October 2014. In this study, we analyzed the data extracted from national varicella surveillance, including pediatric sentinel surveillance from 2000 to 2017 and hospitalized varicella surveillance from the 38th week of 2014 to the 37th week of 2017. Compared with the 2000–2011 baseline data, the number of varicella cases per sentinel decreased substantially by 76.6% overall and by 88.2% among children aged 1–4 years in 2017. Of 997 hospitalized patients, we found a decreasing trend in the number of cases among children aged <5 years. We also found a decreasing trend in the number of cases with complications among children aged 1–4 years. Data on the self-reported transmission sites in 35.5% (354/997) of the hospitalized varicella patients showed that transmission of varicella zoster virus (VZV) occurred frequently in household, at school for young children, in the workplace for adults, and at hospital for all age groups. Data from 29.0% (289/997) of the hospitalized patients with a self-reported source of infection showed that transmission of VZV occurred from a patient with herpes zoster (HZ) in 30.4% (88/289) of cases. Our data demonstrate a substantial decrease in the number of varicella cases in young children following introduction of routine childhood vaccination program with two-dose varicella vaccination in Japan. These data highlight the unique aspects of transmission sites across age groups and the important role of HZ cases in disease circulation.

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.

The effects of school holidays on transmission of varicella zoster virus, England and Wales, 1967-2008.

BackgroundChanges in children’s contact patterns between termtime and school holidays affect the transmission of several respiratory-spread infections. Transmission of varicella zoster virus (VZV), the causative agent of chickenpox, has also been linked to the school calendar in several settings, but temporal changes in the proportion of young children attending childcare centres may have influenced this relationship.MethodsWe used two modelling methods (a simple difference equations model and a Time series Susceptible Infectious Recovered (TSIR) model) to estimate fortnightly values of a contact parameter (the per capita rate of effective contact between two specific individuals), using GP consultation data for chickenpox in England and Wales from 1967–2008.ResultsThe estimated contact parameters were 22–31% lower during the summer holiday than during termtime. The relationship between the contact parameter and the school calendar did not change markedly over the years analysed.ConclusionsIn England and Wales, reductions in contact between children during the school summer holiday lead to a reduction in the transmission of VZV. These estimates are relevant for predicting how closing schools and nurseries may affect an outbreak of an emerging respiratory-spread pathogen.

Transmission of Varicella Zoster Virus From Individuals With Herpes Zoster or Varicella in School and Day-care Settings

Transmission of Varicella Zoster Virus From Individuals With Herpes Zoster or Varicella in School and Day-care Settings

Transmission of Varicella Zoster Virus From Individuals With Herpes Zoster or Varicella in School and Day Care Settings

Because the varicella incidence has declined following varicella vaccine licensure, herpes zoster (HZ) cases may play a larger role in varicella zoster virus (VZV) transmission. We investigated how HZ and varicella cases contribute to the varicella incidence in schools and day care centers. Surveillance data collected in Philadelphia during September 2003-June 2010 were analyzed. A varicella case was considered to be sporadic if it was reported from a school or day care facility >6 weeks after or ≥10 days before other reports of VZV transmission. A varicella case was considered to be secondary if it occurred 10-21 days after report of a case of HZ or sporadic varicella. Analysis compared VZV transmission from individuals with HZ or sporadic varicella, stratified by varicella vaccination status and disease severity. Of 290 HZ cases reported, 27 (9%) resulted in 84 secondary varicella cases. Of 1358 sporadic varicella cases reported, 205 (15%) resulted in 564 secondary varicella cases. Approximately half of the HZ and sporadic varicella cases resulted in single secondary cases. The proportion of individuals who had secondary cases with mild disease was similar for those exposed to HZ and those exposed to varicella (70% and 72%, respectively). VZV transmission was highest from unvaccinated individuals with sporadic varicella (P < .01). VZV transmission from individuals with HZ contributes to varicella morbidity. More research is needed to understand risk factors and guide recommendations for preventing VZV transmission from individuals with HZ.

VZV infection of keratinocytes: production of cell-free infectious virions in vivo.

Varicella-zoster virus (VZV) is the cause of varicella (chickenpox) and zoster (shingles). Varicella is a primary infection that spreads rapidly in epidemics while zoster is a secondary infection that occurs sporadically as a result of the reactivation of previously acquired VZV. Reactivation is made possible by the establishment of latency during the initial episode of varicella. The signature lesions of both varicella and zoster are cutaneous vesicles, which are filled with a clear fluid that is rich in infectious viral particles. It has been postulated that the skin is the critical organ in which both host-to-host transmission of VZV and the infection of neurons to establish latency occur. This hypothesis is built on evidence that the large cation-independent mannose 6-phosphate receptor (MPR(ci)) interacts with VZV in virtually all infected cells, except those of the suprabasal epidermis, in a way that prevents the release of infectious viral particles. Specifically, the virus is diverted in an MPR(ci)-dependent manner from the secretory pathway to late endosomes where VZV is degraded. Because nonepidermal cells are thus prevented from releasing infectious VZV, a slow process, possibly involving fusion of infected cells with their neighbors, becomes the means by which VZV is disseminated. In the epidermis, however, the maturation of keratinocytes to give rise to corneocytes in the suprabasal epidermis is associated uniquely with a downregulation of the MPR(ci). As a result, the diversion of VZV to late endosomes does not occur in the suprabasal epidermis where vesicular lesions occur. The formation of the waterproof, chemically resistant barrier of the epidermis, however, requires that constitutive secretion outlast the downregulation of the endosomal pathway. Infectious VZV is therefore secreted by default, accounting for the presence of infectious virions in vesicular fluid. Sloughing of corneocytes, aided by scratching, then aerosolizes the virus, which can float with dust to be inhaled by susceptible hosts. Infectious virions also bathe the terminals of those sensory neurons that innervate the epidermis. These terminals become infected with VZV and provide a route, retrograde transport, which can conduct VZV to cranial nerve (CNG), dorsal root ganglia (DRG), and enteric ganglia (EG) to establish latency. Reactivation returns VZV to the skin, now via anterograde transport in axons, to cause the lesions of zoster. Evidence in support of these hypotheses includes observations of the VZV-infected human epidermis and studies of guinea pig neurons in an in vitro model system.

The Safety Profile of Varicella Vaccine: A 10‐Year Review

Varivax (varicella virus vaccine live [Oka/Merck]; Merck), a live attenuated varicella vaccine, is indicated for vaccination against varicella in appropriate individuals > or =12 months of age. The 10-year safety profile for Varivax is described using data submitted to Merck from routine global postmarketing surveillance, combined with information from a Varicella Zoster Virus Identification Program, which uses polymerase chain reaction (PCR) analysis to identify the presence and strain of VZV in selected specimens. There were 16,683 reports worldwide voluntarily submitted to Merck, for an overall reporting rate of 3.4 reports/10,000 doses of vaccine distributed. PCR analysis of vesicular rashes that occurred within the first 2 weeks after vaccination was more likely to identify wild-type varicella-zoster virus (VZV), whereas the presence of Oka VZV was generally associated with vesicular rashes that occurred 15-42 days after vaccination. Reports of breakthrough varicella that occurred >42 days after vaccination were associated with wild-type VZV. Among 697 herpes zoster reports, PCR analysis identified Oka VZV in 57 reports and wild-type VZV in 38 reports. There were no primary neurologic adverse events associated with Oka VZV. Secondary transmission of Oka VZV from vaccine recipients with postvaccination vesicular rashes was identified in 3 susceptible household contacts. Disseminated Oka VZV was identified in 6 immunocompromised patients and 1 patient with Down syndrome. This review has shown that the vaccine is generally safe and well tolerated.

Comparison of the dynamics and correlates of transmission of Herpes Simplex Virus-1 (HSV-1) and Varicella-Zoster Virus (VZV) in a sample of the Israeli population

Herpes simplex virus types-1 (HSV-1) and Varicella-zoster virus (VZV) are herpes viruses that share many characteristics. However, HSV-1 spreads by close contact while VZV spreads mainly by the airborne route. In this study we compared the dynamics and correlates of transmission of these viruses in the same population. In 2000-2001, 1555 sera from an age-stratified general population sample were tested using commercial ELISA kits to measure type-specific HSV-1 and varicella IgG antibodies. The VZV seroprevalence increased rapidly with age reaching 50% seropositivity by the age of 3 years, while HSV-1 reached 50% seropositivity at the age of 14 years. The highest VZV force of infection was in the 3.5-5.5-year age group followed by the 5.5-10.5 years age group, while for HSV-1 the age specific force of infection was substantially lower and stable over the various age groups. Multivariate analysis revealed that HSV-1 seroprevalence was significantly, independently associated with age, country of birth, country of origin, ethnicity, socio-economic status and VZV sero-status. Only age, country of origin and HSV-1 sero-status were found to be associated with VZV seropositivity. In developed countries such as Israel the transmission of VZV is much quicker and less dependent on socioeconomic status as compared with HSV-1.

Transition of Humoral Immunity and Clinical VZV Reactivation in Hematopoietic Stem Cell Transplantation Recipients.

Reactivation of varicella-zoster virus (VZV) is common among recipients of hematopoietic stem cell trasnplantation (HSCT). In this setting, VZV infection can occur frequently as localized zoster (shingles) and sometimes as disseminated varicella (chickenpox) with or without visceral involvement, which results in a high mortality rate. Previous studies revealed that VZV-specific memory T cells play a crucial role in suppressing reactivation. Although varicella zoster immunoglobulin is used as a prophylactic and treatment modality in some contries, the role of humoral immunity against VZV infection has been poorly evaluated. The aim of the study was to identify the relationship between quantitative transition of VZV antibody titers and clinical manifestation of VZV infection in HSCT recipients. Thirteen patients with VZV infection after HSCT (7 males, 6 females; age: 21–65 years, median age: 35 years) were enrolled. Eleven patients (allo, 7; auto, 4) suffered localized zoster. Two patients (both allo) suffered systemic varicella with visceral involvement (1 with acute abdomen and 1 with interstitial pneumonia). All patients were treated with acyclovir. Seven patients who had been followed for at least 3 years after HSCT without clinical VZV infection were studied as control subjects (4 males, 3 females; age: 16–40 years, median age: 28 years; allo, 6; auto, 1). We retrospectively studied transition of anti-VZV-IgG titer by the IAHA and gpELISA method (before and at 3, 6, 12, 24, 36 months after HSCT) and VZV-DNA by realtime PCR during clinical VZV infection (onset and paired serum) using cryopreserved serum samples. All patients were seropositive for VZV before HSCT. One of the patients (the most severe case) had become seronegative before systemic varicella developed. However, VZV infections in the other 12 patients occurred despite the persistent existence of anti-VZV (IAHA:x8 to >x256; median x32). There are no statistically significant differences between anti-VZV titers in the 13 patients with VZV infection and those in the 7 controls at each time point. Acceleration of the titer (>x4) was not observed in any of the 9 recipients with VZV infection within the first 6 months after HSCT but was observed in 3 of 4 recipients with VZV infection after 6 months (Figure 1). Four available samples at onset of VZV infection (varicella, 2; zoster, 2) were all positive for VZV-DNA (94.4 to 12173.3 copies /ml serum) by realtime PCR, whereas VZV was undetectable in all paired sera (2 to 5 weeks after onset). Pre-existing anti-VZV titer (gpELISA) and serum viral load were inversely correlated (Figure 2). In HSCT recipients, pre-existing antibody does not prevent development of VZV reactivation but may contribute to decreased viral load, resulting in a mild clinical course. Despite the localized clinical feature of zoster, VZV was detected in serum samples from zoster patients. Clinicians should be aware of the risk of airborne transmission of VZV from HSCT recipients with either varicella or zoster. [Display omitted]

Seroprevalence and force of infection of varicella-zoster virus in Luxembourg

A serological prevalence survey was carried out in Luxembourg during 2000-2001 to determine the antibody status of the Luxembourg population against vaccine-preventable infections including varicella-zoster virus (VZV). ELISA tests performed on 2679 sera indicated that 96 (3.6%) of the study population were seronegative. Age-specific seroprevalence rose rapidly from approximately 70% at age 4 years to 90% at age 6 years to 95% at age 12 years. Significant heterogeneity of seroprevalence was observed between the six different primary schools. For age groups 0-5, 6-11 and 12+ years, we estimated an annual force of infection of 0.361 [95% confidence interval (CI) 0.31-0.415)], 0.204 (95% CI 0.12-0.29) and 0.05 (95% CI 0.024-0.082) respectively. Our results indicate that transmission of VZV is highest in children below the age of 6 years and that much lower levels of VZV transmission occur in secondary schools and throughout adulthood.

Seroprevalence, incidence of prenatal infections and reliability of maternal history of varicella zoster virus, cytomegalovirus, herpes simplex virus and parvovirus B19 infection in South‐Western Finland

To study seroprevalence and incidence and fetal transmission of varicella zoster virus (VZV), cytomegalovirus (CMV), herpes simplex virus (HSV) types 1 and 2 and parvovirus B19 infections during pregnancy and to evaluate the reliability of maternal past history of VZV, HSV and parvovirus infections. Prospective study of parturient women. South-Western Finland. Five hundred and fifty-eight parturient women. IgG and IgM antibodies against VZV, CMV, HSV-1 and -2, and parvovirus B19 were measured from maternal serum in the first trimester and at delivery and from cord serum, mother's own information of her past infections was compared with her serological status. Seroprevalence, seroconversions and fetal transmission of VZV, CMV, HSV and parvovirus B19, reliability of maternal history of VZV, HSV and parvovirus B19. Seroprevalences were 96.2% for VZV, 56.3% for CMV, 54.3% for HSV, 46.8% for HSV-1, 9.3% for HSV-2 and 58.6% for parvovirus B19. Parity was associated with CMV seropositivity, maternal age differed only between HSV-2 seropositive and seronegative women, while area of residence (urban or rural) had no effect. Six seroconversions were observed: two VZV, one CMV and three parvovirus infections. No cases of primary HSV infections occurred. Fetal transmission was observed in two cases of parvovirus infection. No infants with anti-CMV IgM antibodies were born to CMV immunised women. False positive history of chickenpox was given only by 1.5% of the women, history of herpes infections was less reliable, and history of parvovirus infection was unreliable. Seroprevalence and the risk of viral infections during pregnancy cannot be extrapolated from one pregnant population to another.

The seroepidemiology of varicella in Italy.

We conducted a seroepidemiological study to evaluate the potential impact of mass varicella vaccination on the transmission of varicella-zoster virus (VZV) in Italy, where vaccination is not mandatory. We tested 3179 serum samples, collected from September 1996 to October 1997, for specific anti-VZV antibodies using a commercially available ELISA. The results confirmed that varicella typically involves children (82.1% seroprevalence among 10- to 14-year-olds) and that the mean age of acquiring the infection seems to be increasing. The results also revealed that southern Italy, compared to the rest of the country, has a greater circulation of VZV and an earlier age of acquisition. The potential impact of mass vaccination among 12- to 18-month-old children on the epidemiological trend of the infection must be carefully considered, in that failure to reach high levels of coverage could lead to an increase in the mean age of acquisition, which is already occurring in Italy.

Report of the Council on Scientific Affairs, American Medical Association: immunization of healthcare workers with varicella vaccine.

In June 1996, a resolution was introduced to the House of Delegates of the American Medical Association (AMA) asking the AMA to advocate that healthcare workers be given the informed option of receiving the varicella vaccine. The AMA Council on Scientific Affairs studied this issue and presented this report to the House of Delegates in June 1997. Information for the report was derived from published literature and from personal communications with medical and public health experts and the vaccine manufacturer. Nosocomial outbreaks of varicella-zoster virus (VZV) can result in serious morbidity and mortality. Serological testing of healthcare workers and immunization of nonimmune individuals is recommended by infection control and infectious disease experts to prevent nosocomial transmission of VZV. While current data indicate that the vaccine is safe and poses minimal risks to both adults and children, ongoing research should address various concerns about the long-term safety, efficacy, and epidemiological impact of more widespread use of the vaccine. Unless contraindicated, all susceptible healthcare workers should receive the varicella vaccine. Whereas individuals with a definite history of VZV infection can be considered immune, those with a negative or uncertain history should undergo serological testing and, if seronegative, should be immunized.

Special Report: Report of the Council on Scientific Affairs American Medical Association: Immunization of Healthcare Workers with Varicella Vaccine

OBJECTIVE: In June 1996, a resolution was introduced to the House of Delegates of the American Medical Association (AMA) asking the AMA to advocate that healthcare workers be given the informed option of receiving the varicella vaccine. The AMA Council on Scientific Affairs studied this issue and presented this report to the House of Delegates in June 1997. METHODS: Information for the report was derived from published literature and from personal communications with medical and public health experts and the vaccine manufacturer. FINDINGS: Nosocomial outbreaks of varicella-zoster virus (VZV) can result in serious morbidity and mortality. Serological testing of healthcare workers and immunization of nonimmune individuals is recommended by infection control and infectious disease exp rts to prevent nosocomial transmission of VZV. While current data ndicate that the vaccine is safe and poses minimal risks to both adults and children, ongoing research should address various concerns about the long-term safety, efficacy, and epidemiological impact of more widespread use of the vaccine. CONCLUSION: Unless contraindicated, all susceptible healthcare workers should receive the varicella vaccine. Whereas individuals with a definite history of VZV infection can be considered immune, those with a negative or uncertain history should undergo serological testing and, if seronegative, should be immunized (Infect Control Hosp Epidemiol 1998;19:348-353). Varicella-zoster virus (VZV) is a highly contagious herpes virus responsible for two common diseases: varicella (chickenpox) and herpes zoster (shingles).1 Varicella results from primary VZV infection and is a common childhood illness associated with fever and a generalized pruritic rash. Following primary infection, VZV establishes itself in cells of the dorsal root ganglia where it remains latent for years. Reactivation results in herpes zoster, a localized, painful, vesicular rash involving one or adjacent dermatomes. The incidence of herpes zoster increases with age and immunosuppression. Every year in the United States, thousands are hospitalized, and dozens die due to complications of VZV infection. Groups such as infants under 1 year of age, adults, the immunocompromised, and pregnant women are at increased risk for developing complications. It is important for healthcare workers, especially those working with high-risk groups, to know their VZV immune status. If susceptible personnel are exposed, they are considered potentially infectious for up to 21 days.1,2 Because the disease is communicable 1 to 2 days before symptoms begin, exposed employees may need to be reassigned temporarily or furloughed to prevent transmission to susceptible coworkers, patients, and visitors. In 1995, a varicella virus vaccine was approved for use in the United States. Administration of the vaccine to healthcare workers could reduce nosocomial transmission of VZV. Furthermore, considerable cost and labor savings could be realized by avoiding expensive and potentially disruptive infection control measures.