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Prevention and control of varicella-zoster virus in hospitals
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Prevention and control of varicella-zoster virus in hospitals
All topics are updated as new evidence becomes available and our peer review process is complete.
Literature review current through: Nov 2016. | This topic last updated: Jul 21, 2016.

INTRODUCTION — Varicella-zoster virus (VZV) infection causes two clinically distinct forms of disease: varicella (chickenpox) and herpes zoster (shingles). Primary VZV infection results in the diffuse vesicular rash of varicella, or chickenpox. Endogenous reactivation of latent VZV typically results in a localized skin infection known as herpes zoster, or shingles. Varicella is generally a mild disease in children, although serious complications can sometimes occur (eg, secondary bacterial skin infections and pneumonia). Complications from VZV infection are more common in neonates, adults, or immunocompromised persons.

Because varicella is highly contagious and may cause serious disease, the Centers for Disease Control and Prevention (CDC), the American Academy of Pediatrics (AAP), and infectious disease experts have published recommendations regarding the prevention of VZV among health care personnel, isolation of patients with VZV infection, and the management of patients and health care personnel exposed to VZV. Issues specific to infection control and care of exposed health care personnel are discussed below.

The epidemiology and clinical manifestations of VZV have changed significantly since the introduction of the varicella vaccine. These issues, as well as the diagnosis, treatment, and prevention of varicella infection are discussed elsewhere. (See "Epidemiology of varicella-zoster virus infection: Chickenpox" and "Vaccination for the prevention chickenpox (primary varicella infection)" and "Clinical features of varicella-zoster virus infection: Chickenpox" and "Treatment of varicella (chickenpox) infection" and "Clinical manifestations of varicella-zoster virus infection: Herpes zoster" and "Treatment of herpes zoster in the immunocompetent host".)

IMPORTANCE OF INFECTION CONTROL — Control of VZV is important in health care facilities for the following reasons:

VZV is highly contagious. This is particularly true of patients who present with varicella, compared to those with zoster, who are generally less infectious.

Although varicella in healthy adults is often a relatively benign disease, it may be associated with serious complications, such as pneumonia.

Severe complications, including death, may occur in immunocompromised patients and neonates.

Infection in pregnant women may lead to congenital varicella syndrome or neonatal varicella. (See "Varicella-zoster virus infection in pregnancy".)

GENERAL PRINCIPLES OF VIRAL TRANSMISSION — Humans are the only known hosts of VZV infection. VZV is transmitted primarily from person-to-person by the droplet and airborne routes, and occurs most efficiently when there is close contact. VZV is extremely labile and is therefore unlikely to be transmitted by inanimate objects.

Incubation period of varicella — The incubation period for varicella ranges from 8 to 21 days, but most patients develop disease between days 14 and 16. Patients with varicella become infectious 24 to 48 hours prior to the onset of rash. Normal hosts remain infectious for approximately five days after the onset of the rash, while immunocompromised hosts may remain infectious for a more prolonged period.

Secondary attack rates of VZV — The secondary attack rate of varicella among susceptible persons in the household setting is about 85 percent. Comparable data in hospital settings are not available.

Herpes zoster, the reactivation of VZV, is also infectious, although analysis of household contacts suggests that the risk of transmission is only one-third that of varicella.

NOSOCOMIAL TRANSMISSION — Nosocomial transmission of VZV is well documented from both persons with varicella infection or reactivation disease with herpes zoster.

Transmission from persons with varicella — Varicella may be introduced into the hospital by patients, staff, or visitors with either clinically evident infection or during the incubation phase of the disease [1,2]. Nosocomial transmission of varicella appears to be primarily through the airborne route based on cases among staff and patients who had no direct contact with the index case. Epidemiologic and tracer studies have also confirmed that exposure to airflow from rooms occupied by patients with varicella is a major risk factor for the acquisition of infection among susceptible hosts [1]. However, alternative modes of transmission must be considered, as one hospital outbreak was attributed to varicella exposure during the course of an autopsy [3].

Transmission can even occur among previously vaccinated individuals [4-6]. As an example, an outbreak of varicella was described in a population of pediatric cancer patients in a tertiary pediatric facility. Over approximately 16 days, varicella was detected in seven children (the index case, five secondary cases, and one tertiary case) [4]. Of the seven identified cases, four appeared to represent "breakthrough disease" in previously vaccinated children. An outbreak of breakthrough varicella was also described among patients in a health care facility, where most individuals had neurologic deficits and were receiving rehabilitative therapy [6]. A detailed discussion of breakthrough varicella is found elsewhere. (See "Vaccination for the prevention chickenpox (primary varicella infection)", section on 'Breakthrough varicella'.)

In contrast, transmission of varicella to term infants in the hospital nursery is rare because of transplacental passage of protective maternal antibodies [7]. The management of neonates exposed to varicella is discussed in a separate topic review. (See "Varicella-zoster infection in the newborn", section on 'Management of exposure'.)

Transmission from persons with zoster — The incidence of zoster among patients with altered immune function may be up to 10-fold higher than the general population [8]. Such patients are frequently hospitalized leading to possible nosocomial exposure. Exposure to dermatomal or disseminated zoster has led to clinical varicella in the hospital setting [9-11]. As an example, a hospital outbreak of varicella was reported in four adult patients with diffuse large B cell lymphoma who were treated with rituximab-containing chemotherapy [9]. The patients developed varicella after exposure to a patient with lymphoma who had zoster. Varicella occurred despite all patients having detectable serum anti-varicella zoster virus IgG antibodies before chemotherapy. This outbreak emphasizes the need to place immunocompromised patients with zoster on airborne precautions.

Nosocomial transmission from localized zoster in immunocompetent hosts has rarely been reported [11]; and when these cases do occur, it is felt that transmission commonly results from direct contact with skin lesions. However, there have been reports suggesting that aerosolized virus from skin lesions, and possibly from the respiratory tract, may cause infection, even in those who have no direct patient contact [12-14].

In one long-term care facility, a small outbreak of varicella was reported after a case of herpes zoster was diagnosed in one of the nursing home residents [13]. Clinical samples were collected from three case patients; genotypic analysis showed that the identical varicella-zoster strain was present in all three cases. Furthermore, high concentrations of VZV DNA were detected in environmental samples from the room of the herpes zoster case patient. Two of the three patients did not have any known contact with the index case while the third, a health care provider, had changed her linens. This case is notable since the index case was placed on contact precautions within 24 hours, was appropriately diagnosed and treated with valacyclovir, and her rash was covered with gauze and clothing.

In another case report, recurrent varicella occurred in a seropositive clinician 14 days after examination of an immunocompetent patient with herpes zoster ophthalmicus [14]. The clinician wore gloves at the time of the encounter but did lift bandages to examine the patient, who had initiated antiviral therapy less than 12 hours before.

Varicella-zoster virus DNA has been found to widely contaminate the rooms of patients with dermatomal zoster [13,15] and has been detected by polymerase chain reaction (PCR) on the surface of gauze dressings and in room air purifier filters, supporting the failure of gauze dressing to completely prevent aerosolization of the virus [16]. These findings have implications for infection control measures which are addressed below. (See 'Isolation precautions for patients with herpes zoster' below.)

PREVENTION OF VARICELLA AMONG HEALTH CARE PERSONNEL — To prevent the transmission of varicella to health care personnel, we agree with the Advisory Committee on Immunization Practices/United States Centers for Disease Control and Prevention (CDC), the Hospital Infections Control Practices Advisory Committee/CDC, the American Medical Association, and the Canadian National Advisory Committee on Immunization (NACI), all of whom recommend that all health care personnel (HCP) be immune to VZV [2,7,17-19]. Health care personnel are defined as all paid and unpaid persons working in health care settings who have the potential for exposure to patients and include (but are not limited to) clinicians, nurses, therapists, technicians, pharmacists, laboratory personnel, autopsy personnel, students, trainees, contractual staff, and persons (eg, clerical, dietary, housekeeping, laundry, security, maintenance, administrative, billing, and volunteers) not directly involved in patient care but potentially exposed to infectious agents that can be transmitted to and from health care personnel and patients [2].

Rationale for immunizing susceptible health care personnel — Routine varicella immunization with two doses of varicella vaccine is extremely effective in preventing varicella infection in children and adults and is associated with minimal side effects (eg, pain at injection site). Compelling reasons to attain seroprotection among health care personnel include:

To decrease transmission from health care personnel to hospitalized patients and vice versa.

To decrease the risk of severe morbidity and mortality that may occur with varicella infection among adults and immunocompromised patients.

To avoid the significant costs associated with nosocomial transmission of varicella.

Once varicella exposure has been identified, multiple resources within the hospital must be mobilized at considerable cost including:

The removal of susceptible staff from patient contact following VZV exposures.

The administration of prophylaxis to patients and employees.

The time and effort of hospital staff in evaluating potential VZV exposures.

In health care settings, serologic screening and vaccination of health care personnel susceptible to varicella are felt to be cost-effective for health care facilities [2,20,21]. The CDC recommends that "only health care personnel with evidence of immunity to varicella should care for patients who have confirmed or suspected varicella or herpes zoster" [2].

Establishing susceptibility to infection — Health care personnel should be screened for VZV immunity at the time of initial employment; those without evidence of immunity (ie, previous varicella, herpes zoster, or appropriate immunization) should be immunized if there are no contraindications (table 1). (See 'Active immunization of susceptible health care personnel' below.)

According to the ACIP/CDC, evidence of immunity for HCP includes any of the following [2]:

Written documentation of vaccination with two doses of varicella vaccine.

Laboratory evidence of immunity or laboratory confirmation of disease. Commercial assays can be used to assess disease-induced immunity, but they often lack sensitivity to detect vaccine-induced immunity (ie, they might yield false-negative results) [2]. (See 'Assessment of immunity after immunization' below.)

A diagnosis or verification of a history of herpes zoster by a health care provider.

A diagnosis or verification of a history of varicella disease by a health care provider.

The ACIP/CDC states that verification of a history or diagnosis of typical varicella disease can be provided by any health care provider. In contrast, for persons reporting a history of, or reporting with, an atypical or mild case, they recommend assessment by a physician (or their designee), and one of the following: an epidemiologic link to a typical varicella case or to a laboratory-confirmed case, or evidence of laboratory confirmation if it was performed at the time of acute disease. The ACIP/CDC does not consider a patient as having a valid history of disease when such documentation is lacking since other diseases might mimic mild atypical varicella.

However, the sensitivity of a self-reported history of varicella or zoster was demonstrated in a seroprevalence study of 413 HCP in the United States, where 96 percent of those with a history of VZV infection had positive VZV antibody titers, regardless of when they were born [22]. Thus, we also consider a patient-reported history of varicella as evidence of immunity.

Evidence of immunity for HCP differs somewhat from other patients. As an example, birth before 1980 is not considered sufficient evidence of immunity in HCP, although in other settings this criterion can been used. A discussion of varicella immunity in other populations where vaccination is being considered is found elsewhere. (See "Vaccination for the prevention chickenpox (primary varicella infection)", section on 'Evidence of immunity'.)

Active immunization of susceptible health care personnel — All susceptible health care personnel without a contraindication to immunization should be vaccinated. A second dose should be administered four to eight weeks after the first dose. (See "Vaccination for the prevention chickenpox (primary varicella infection)", section on 'Schedules in the United States'.)

Ideally all susceptible health care personnel are vaccinated prior to employment, and these individuals do not require any restrictions in their work activities [2]. For individuals who are exposed to VZV prior to completing their vaccinations, post-exposure prophylaxis with varicella vaccine is associated with both prevention of infection and lessening of disease severity in those who do become ill [7,23]. (See 'Post-exposure prophylaxis' below.)

Contraindications for varicella vaccine are discussed elsewhere. If the health care provider is pregnant, administration of the varicella vaccine should be postponed until after delivery. If the health care provider is within five months of receipt of immunoglobulin preparation or plasma transfusion, vaccination should be postponed for at least five months after the date of product administration. (See "Vaccination for the prevention chickenpox (primary varicella infection)".)

Health care personnel caring for immunocompromised hosts can receive varicella vaccine since the risk of transmission of vaccine strain virus is low, and no cases of vaccine virus transmission from a recently immunized health care provider to a susceptible patient have been documented [2,24,25].

The CDC recommends that health care personnel who develop a vaccine-related rash after vaccination should avoid contact with persons without evidence of immunity to varicella who are at risk for severe disease until all lesions resolve (ie, are crusted over). For health care providers who develop lesions that do not crust (ie, are macules and papules only), the CDC recommends avoiding contact with at-risk patients until no new lesions appear within a 24-hour period [2]. However, we recommend that health care facilities furlough providers who develop vaccine-related rash until lesions resolve. This is because many hospitalized patients would be at risk for severe disease, and it would not be practical to assess each patient’s immune status to varicella. (See 'Management of exposed susceptible health care personnel' below.)

Assessment of immunity after immunization — Post-immunization serology is not recommended since:

Commercial tests may lack the sensitivity to detect the lower antibody levels associated with vaccination compared with natural infection.

Sensitive tests that are not generally available have indicated that 92 to 99 percent of adults develop antibodies after two doses of varicella vaccine [2].

Documentation of varicella immunization — Standard guidelines should be practiced for varicella immunization, including assessment of contraindications and precautions, medical record documentation, and informed consent. The following information should be recorded in the medical record: employee name, date, vaccine, manufacturer, lot number, site of immunization, and informed consent.

Adverse events of vaccination — In the United States, significant adverse reactions should be reported to the Food and Drug Administration (FDA) via the vaccine adverse events reporting system (VAERS). Side effects of varicella vaccine are discussed elsewhere. (See "Vaccination for the prevention chickenpox (primary varicella infection)", section on 'Adverse events'.)

INFECTION CONTROL MEASURES — The CDC, the American Academy of Pediatrics, and infectious disease experts have published guidelines or algorithms designed to aid clinicians in the control of nosocomial exposures [1,26,27].

Isolation precautions for patients with varicella — Patients with varicella should be placed on airborne and contact precautions [2,28]. A detailed description of these infection control precautions is found elsewhere. (See "Infection prevention: Precautions for preventing transmission of infection", section on 'Contact precautions' and "Infection prevention: Precautions for preventing transmission of infection", section on 'Airborne precautions'.)

In addition, only health care personnel (HCP) with evidence of immunity to varicella should care for patients who have confirmed or suspected varicella or herpes zoster. All HCP should wear an N95 respirator when in the room, even if they are considered immune (eg, they completed the vaccine series or have a history of disease). This is because varicella vaccine is not 100 percent effective in preventing infection, and providing consistent recommendations helps ensure adherence to these precautions which provide respiratory protection. Similarly, all visitors should be considered susceptible, and should wear a mask when in the room.

We are unaware of any nosocomial outbreaks related to infected patients who were placed in negative pressure private rooms and on airborne precautions. However, one report documented a case of varicella occurring in a susceptible health care provider who never entered the patient's negative pressure isolation room, but remained in the outside corridor passing materials in through an open door [29]. This incident emphasizes the need for strict observation of airborne precautions, as recommended by the CDC [26,28].

Given the current low incidence of tuberculosis in the United States, it is likely that many hospitals do not have an adequate number of rooms meeting the OSHA tuberculosis requirements (ie, with direct out exhausted air) to use these rooms to isolate patients with VZV infections. In these situations, we recommend a negative pressure private room or a neutral pressure room and the use of a portable high efficiency particulate air (HEPA) unit placed between the patient and the door. In all of these situations, the door to the room should remain closed except when personnel are entering or leaving the room.

For exposed sero-susceptible patients, we agree with the CDC and the American Academy of Pediatrics which suggest isolation of hospitalized patients using these precautions from the eighth day after the first exposure to the 21st day after the date of the last exposure [26,27].

Isolation precautions for patients with herpes zoster — The CDC recommends that all patients with disseminated zoster and immunocompromised patients with dermatomal zoster be placed in the same isolation precautions as those with varicella described above [28].

In contrast, the CDC recommends that HCP who care for immunocompetent patients with dermatomal zoster use standard precautions alone, without airborne and contact isolation precautions [26,28]. A description of standard precautions is presented elsewhere. (See "Infection prevention: Precautions for preventing transmission of infection", section on 'Standard precautions'.)

Suspected airborne or droplet transmission has been reported which suggests that covering herpes zoster lesions with gauze may sometimes be inadequate to prevent aerosolization of varicella virus in immunocompetent hosts [10,11,13,14,16]. However, we support the current CDC recommendations, as only a few reported infections have occurred when CDC recommendations were followed. (See 'Transmission from persons with zoster' above.)

EVALUATION OF EXPOSURE AMONG PERSONNEL — All personnel potentially exposed to varicella, disseminated zoster, and uncovered lesions of localized zoster in the community or health care setting/workplace should be evaluated as soon as feasible by the Occupational Health Service, and VZV infection in the source patient should be confirmed.

For all exposures, the potential for VZV acquisition should be assessed. The risk varies based upon the duration and proximity of the exposure, the immune status of the health care worker and patient, and the type of disease.

The University of North Carolina Hospitals defines VZV exposure for a susceptible health care provider who did not wear a mask or N95 respirator as being within a confined airspace (ie, same room) or having face-to-face contact with a patient who is infected with VZV. Experts differ regarding the duration of contact; some suggest five minutes, whereas others suggest up to one hour; all agree that this does not include transient contact [2].

MANAGEMENT OF EXPOSED PREVIOUSLY VACCINATED HEALTH CARE WORKERS

The ACIP recommends that exposed health care personnel previously immunized with two doses of varicella vaccine be monitored daily during days 8 to 21 after exposure for fever, skin lesions, and systemic symptoms suggestive of varicella. This recommendation is based on the observation that approximately one-third of persons who receive vaccine develop break through disease. Health care personnel can be monitored directly by an occupational health program or by infection-control practitioners. Alternatively, they can be instructed to immediately report fever, headache, constitutional symptoms, and/or any atypical skin lesions. Health care personnel should be excluded from a work facility immediately if symptoms and/or signs occur.

MANAGEMENT OF EXPOSED SUSCEPTIBLE HEALTH CARE PERSONNEL — Susceptible health care personnel may not have been vaccinated at the beginning of employment as a result of a medical contraindication or due to nonadherence to immunization procedures and policies. These individuals may need post-exposure prophylaxis; the type of prophylaxis will depend on the specific circumstances surrounding the lack of prior immunization. (See 'Post-exposure prophylaxis' below.)

Work furlough — Certain health care providers who have been exposed to VZV (varicella, disseminated herpes zoster, and uncovered lesions of a localized zoster) should be excluded from work from days 8 to 21 after exposure [2]. These recommendations are based on expert opinion and include:

Health care providers who are susceptible to varicella

Health care providers who have received only a single dose of varicella vaccine

Health care providers who received the second dose of varicella vaccine >five days after exposure

Post-exposure prophylaxis — Post-exposure prophylaxis for health care personnel typically involves the administration of varicella vaccine. Other less commonly used interventions include VariZIG or acyclovir. The appropriate use of these various interventions in health care personnel is discussed below. Post-exposure prophylaxis for patients exposed to VZV is discussed elsewhere. (See "Post-exposure prophylaxis against varicella-zoster virus infection".)

Varicella vaccine — Varicella vaccine for post-exposure prophylaxis is almost 80 percent effective in preventing illness and is also highly effective in modifying varicella severity when administered within three days of exposure [23]. The efficacy of giving the vaccine more than three days after exposure has not been established.

Among health care personnel who are unvaccinated — Post-exposure vaccine should be provided as soon as possible to previously unvaccinated health care personnel who have been exposed to VZV [2]. The ACIP has made this recommendation because vaccination within three to five days of exposure to varicella-zoster virus might modify the disease if infection occurs, and vaccination >five days post-exposure can induce protection against subsequent exposures.

Among health care personnel who have received one dose of vaccine — Exposed health care personnel who have received one dose of vaccine should receive the second dose within three to five days after exposure to the rash (provided >four weeks have elapsed after the first dose). After vaccination, management of the exposed health care provider is similar to that of two-dose vaccine recipients. Individuals who receive the second dose >five days after exposure will need to be furloughed. (See 'Management of exposed previously vaccinated health care workers' above and 'Work furlough' above.)

Rash among exposed health care personnel who received post-exposure vaccine — A rash that occurs in an exposed health care worker who has received post-exposure vaccine may be due to either the wild-type virus or vaccine strain. Rashes that occur within the first two weeks after immunization are often due to wild-type varicella, whereas rashes occurring 15 to 42 days after vaccination are more likely due to vaccine-associated virus (ie, Oka VZV) [30]. In either case, a health care provider with a vesicular rash following varicella vaccine should be furloughed. (See 'Work restrictions' below.)

Varicella-zoster immune globulin — Exposed seronegative health care personnel who are immunocompromised or pregnant, and who did not receive vaccine at the initiation of employment because of medical contraindications, should be considered for varicella-zoster immune globulin (VariZIG) [31]. Ideally, VariZIG should be administered as soon as possible after exposure (preferable within 96 hours) within 10 days [2,31]. Varicella-zoster immune globulin is discussed separately. (See "Post-exposure prophylaxis against varicella-zoster virus infection", section on 'VariZIG'.)

Health care personnel who receive VariZIG should be furloughed from day 8 through day 28 postexposure, as VariZIG may ameliorate, but not prevent, varicella. Antiviral therapy should be initiated if the person develops signs of varicella disease [2].

Antiviral Therapy — If VariZIG is unavailable, oral acyclovir (800 mg 5 times daily for days 8 through 21 after exposure), famciclovir (500 mg 3 times daily for days 8 through 21 after exposure), or valacyclovir (1000 mg 3 times daily for days 8 through 21 after exposure) may be used in susceptible health care personnel who are immunocompromised or pregnant. Although post-exposure antivirals have not been studied in these populations, their appropriateness can be extrapolated from several small studies in healthy children and those with leukemia that suggest oral acyclovir, when initiated within three to seven days after exposure, and continued through the incubation period, is effective in lessening disease severity and may prevent infection [32-37]. (See "Post-exposure prophylaxis against varicella-zoster virus infection", section on 'Acyclovir for postexposure prophylaxis'.)

Follow-up serologic testing should be performed for any health care provider who receives post-exposure prophylaxis with acyclovir to determine if the patient has seroconverted; receipt of prophylaxis may not eliminate the possibility of future varicella infection [35].

Antiviral therapy is not indicated for prophylactic use among otherwise healthy adults without evidence of immunity. Immunization with varicella vaccine is the method of choice in these adults.

MANAGEMENT OF HEALTH CARE PERSONNEL WITH VZV INFECTION

Diagnosis of VZV in health care workers — History and physical examination alone are usually sufficient to diagnose varicella or zoster. However, vesicular fluid can be sent for direct fluorescent antibody (DFA) staining, culture, or polymerase chain reaction (PCR) analysis if any uncertainty regarding the diagnosis exists or laboratory confirmation is desired.

All health care personnel with VZV infection should be evaluated by the Occupational Health Service. Following confirmation of infection, staff and patients exposed to the health care provider should be appropriately managed.

Treatment — Treatment recommendations for adults and women during pregnancy are discussed elsewhere. (See "Treatment of varicella (chickenpox) infection" and "Varicella-zoster virus infection in pregnancy".)

Work restrictions — Health care personnel should be furloughed if they develop varicella or disseminated herpes zoster, or if they are immunocompromised and develop dermatomal herpes zoster. They may return to work when clinically well and after all lesions are dried and crusted (usually about five days after symptoms develop).

Healthy individuals with dermatomal herpes zoster not on exposed areas of the body may continue to work so long as the area is able to be covered with a sterile dressing and is under clothes. These individuals should not care for high-risk patients until their skin lesions have become dry and crusted.

SUMMARY AND RECOMMENDATIONS

Varicella-zoster virus infection is the causative agent of two diseases: varicella (chickenpox), the primary infection; and herpes zoster (shingles), an illness due to reactivation of latent VZV infection. Varicella is generally a mild disease in children, but can cause serious infection in neonates, adults, or immunocompromised persons. (See 'Introduction' above.)

Control of varicella is important in health care facilities since varicella-zoster virus is highly contagious. (See 'Importance of infection control' above.)

The incubation period of varicella ranges from 8 to 21 days after exposure, but most patients develop disease between days 14 and 16. Patients with varicella become infectious 24 to 48 hours prior to the onset of rash. (See 'General principles of viral transmission' above.)

Nosocomial transmission of VZV is well documented from either persons with clinical varicella infection or herpes zoster, although the rates of transmission are much higher from patients with varicella. VZV appears to be transmitted primarily person-to-person by the droplet and airborne route and occurs most efficiently when there is close contact. (See 'Nosocomial transmission' above.)

Nosocomial varicella has also occurred among staff and patients who had no direct contact with the index case, supporting airborne transmission as a mode of spread. (See 'Nosocomial transmission' above.)

Health care personnel should be screened for immunity to varicella-zoster. Evidence of immunity includes: written documentation of two doses of varicella vaccine; laboratory evidence of immunity; or diagnosis of varicella disease or zoster by a health care provider. All other health care personnel should be assumed to be susceptible to infection. (See 'Prevention of varicella among health care personnel' above.)

We recommend that all susceptible health care personnel should be vaccinated, unless there is a contraindication to immunization. Postimmunization serology is not recommended after immunization (Grade 1A). (See 'Prevention of varicella among health care personnel' above.)

We recommend that all patients with varicella or disseminated zoster, and immunocompromised patients with dermatomal zoster, be placed in private rooms meeting standards for isolation of tuberculosis patients (Grade 1B). This is consistent with current CDC guidelines. In addition, contact precautions should be used as well. (See 'Infection control measures' above.)

The CDC recommends only standard precautions for non-immunocompromised patients with dermatomal herpes zoster infection. However, there are case reports of nosocomial acquisition from dermatomal zoster in immune competent patients when only contact precautions were used. (Grade 2C). (See 'Infection control measures' above.)

Exposed health care personnel who were previously immunized with two doses of varicella vaccine should be monitored 8 to 21 days after exposure for symptoms of infection. (See 'Management of exposed previously vaccinated health care workers' above.)

All susceptible health care personnel exposed to varicella-zoster require post-exposure prophylaxis. For health care personnel without contraindications to vaccination, we recommend varicella vaccination (Grade 1B). VariZIG and acyclovir are suitable alternatives for health care personnel with contraindications to vaccination, such as immunosuppression or pregnancy. (See 'Management of exposed susceptible health care personnel' above.)

Susceptible health care personnel who have been exposed to VZV (varicella, disseminated herpes zoster, and uncovered lesions of a localized zoster) should be excluded from work from days 8 to 21 after exposure. (See 'Work furlough' above.)

Management of health care personnel with varicella or herpes zoster infection depends on the immune status of the health care worker as well as the type of disease they develop. (See 'Management of health care personnel with VZV infection' above.)

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