Version July 2025
INTRODUCTION —
Varicella-zoster virus (VZV) causes two clinically distinct forms of disease: varicella (chickenpox) and herpes zoster (shingles). Primary VZV infection results in the diffuse vesicular rash of varicella. Reactivation of latent VZV typically results in a localized skin infection known as herpes zoster, or shingles. Complications from VZV infection are more common in neonates, adults, immunocompromised, or pregnant persons.
Varicella and disseminated herpes zoster are highly contagious. Uncomplicated herpes zoster is less easily spread, although person-to-person transmission can occur.
This topic will discuss issues specific to infection control and management of health care personnel (HCP) exposed to VZV. The diagnosis, treatment, and prevention of varicella infection are discussed elsewhere. (See "Epidemiology of varicella-zoster virus infection: Chickenpox" and "Vaccination for the prevention of chickenpox (primary varicella infection)" and "Clinical features of varicella-zoster virus infection: Chickenpox" and "Treatment of varicella (chickenpox) infection" and "Epidemiology, clinical manifestations, and diagnosis of herpes zoster" and "Treatment of herpes zoster".)
TRANSMISSION OF VARICELLA ZOSTER VIRUS
General principles — Nosocomial transmission of VZV is well documented in both persons with varicella and herpes zoster. VZV can be spread from person to person by direct contact with lesions, inhalation of aerosols from the vesicular fluid of skin lesions, and possibly via respiratory secretions from patients with varicella. VZV is extremely labile and is therefore unlikely to be transmitted by inanimate objects. (See "Epidemiology, clinical manifestations, and diagnosis of herpes zoster", section on 'Transmission'.)
Varicella
●Period of infectiousness – The incubation period for varicella ranges from 10 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. Patients are infectious until all lesions have dried and crusted over. Immunocompetent persons remain infectious for approximately five days after the onset of the rash, while immunocompromised patients may remain infectious for a more prolonged period.
●Person-to-person transmission – Varicella may either be introduced into health care settings by patients, staff, or visitors with clinically evident infection or during the incubation phase of the disease [1,2].
Transmission of VZV from patients with varicella can occur through direct contact with lesions, through inhalation of aerosols from vesicular fluid of skin lesions, and possibly through infectious respiratory secretions.
Cases of varicella have been reported in staff and patients without direct contact with the index case [1]. Epidemiologic and tracer studies have 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]. One hospital outbreak was attributed to VZV exposure during the course of an autopsy [3].
●Risk of acquiring varicella after an exposure
•HCP without prior varicella infection or vaccination – The secondary attack rate of varicella among susceptible persons in the household setting can be as high as 85 percent [4-6]. Comparable data in health care settings are not available.
•HCP who are fully vaccinated – The risk of developing varicella is significantly reduced in fully vaccinated patients but may occur (breakthrough disease). Although the risk of breakthrough infection in fully immunized adults has not been established, in children the estimated risk of breakthrough infection is 2.2 cases per 1000 person-years, based on a meta-analysis [7]. (See "Vaccination for the prevention of chickenpox (primary varicella infection)", section on 'Benefits of immunization'.)
Breakthrough disease most commonly occurs in immunocompromised persons [8-10]. Persons with breakthrough disease are still contagious to others, although they are usually less so than unvaccinated persons with varicella [4,11]. A detailed discussion of breakthrough varicella is found elsewhere. (See "Vaccination for the prevention of chickenpox (primary varicella infection)", section on 'Breakthrough varicella'.)
Herpes zoster — Many patients with reactivated VZV, or herpes zoster (shingles), are managed in the outpatient setting. However, the incidence of zoster among patients with altered immune function may be up to 10-fold higher than the general population [12]. Such patients are frequently hospitalized, leading to possible nosocomial exposures.
●Period of infectiousness – Patients with herpes zoster are considered infectious from the onset of lesions until all the lesions have crusted. Unlike patients with varicella, there is no transmission prior to the appearance of skin lesions.
●Person-to-person transmission – Transmission of VZV from persons with localized herpes zoster typically results from direct contact with skin lesions. Transmission due to aerosolized virus from skin lesions can also occur. There have been case reports of varicella developing in those who have no direct contact with patients with localized zoster [13-15]. Gauze dressings likely reduce the risk of aerosolization of virus but may not completely prevent it.
In persons with disseminated herpes zoster, transmission also occurs through direct contact with skin lesions. In such patients, the risk of airborne transmission due to aerosolized virus from skin lesions is increased due to higher viral burden and the inability to completely cover widely disseminated lesions. Unlike patients with varicella, airborne transmission in patients with herpes zoster results from aerosolization from skin lesions rather than from respiratory secretions since disseminated zoster rarely involves the lungs.
●Risk of acquiring varicella after an exposure – Although there have been reports of HCP developing varicella after exposure to dermatomal zoster in both immunocompetent and immunocompromised patients [16-18], the exact risk of susceptible HCP developing varicella after exposures to patients with herpes zoster is unknown. In household contacts, the risk of VZV transmission from a person with localized zoster to a susceptible person is about one-third that from an individual with varicella.
The risk of acquiring VZV may be greater in immunocompromised patients. 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 [16]. Despite having previous positive IgG titers, the patients developed varicella after exposure to a patient with lymphoma who had zoster.
Importance of infection prevention — 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 children is often a relatively benign disease, it may be associated with serious complications, such as pneumonia, secondary skin infections, and meningoencephalitis, particularly in neonates, adolescents, and adults.
●Severe complications, including death, may occur in immunocompromised patients and neonates.
●Infection in pregnant persons may lead to congenital varicella syndrome (risk of approximately 2 percent when infection occurs between 8 and 20 weeks of gestation) or neonatal varicella. (See "Varicella-zoster virus (VZV) infection in the newborn".)
●VZV exposures require extensive contact investigations and infection control efforts and may result in HCP furloughs, disrupting health care activities [19].
PREVENTING VARICELLA IN THE HEALTH CARE SETTING —
To prevent transmission of varicella in health care settings, it is important to implement appropriate infection prevention measures for patients with varicella or herpes zoster and to ensure health care personnel (HCP) are immune [2,20-25]. HCP are defined as all paid and unpaid persons working in health care settings who have the potential for direct or indirect exposure to patients or infectious materials, including body substances or contaminated supplies, devices, equipment, environmental surfaces, or air [26]. This includes students and trainees, licensed independent practitioners, contracted HCP, volunteers, and others.
Establishing susceptibility to infection — HCP should be evaluated for VZV immunity at the time of initial employment; those without evidence of immunity should be immunized if there are no medical contraindications (table 1). In addition, it is reasonable to review and update immunization/serology records for longstanding HCP who may be at increased risk for exposure (eg, emergency room employees), as policies regarding demonstration of VZV immunity may have changed since they were initially employed. (See 'Vaccination of susceptible HCP' below.)
According to the Advisory Committee on Immunization Practices (ACIP)/United States Centers for Disease Control and Prevention (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 (a positive IgG titer) or laboratory confirmation of disease (confirmation of VZV from a clinical sample). Commercial IgG assays can be used to assess disease-induced immunity, but they lack sensitivity to detect vaccine-induced immunity (ie, they might yield false-negative results) [2].
●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 presenting with an atypical or mild case, they recommend assessment by a health care provider plus 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 person as having a valid history of disease when such documentation is lacking because other diseases might mimic mild atypical varicella.
Evidence of immunity for HCP differs somewhat from other persons. In particular, birth in the United States before 1980 is not considered sufficient evidence of immunity in HCP, although in other settings this criterion may be used. A discussion of varicella immunity in other populations eligible for vaccination is presented elsewhere. (See "Vaccination for the prevention of chickenpox (primary varicella infection)", section on 'Evidence of immunity'.)
In health care settings, serologic screening and vaccination of HCP susceptible to varicella is felt to be cost-effective [2,27,28]. Once a varicella exposure has been identified, multiple resources within the health care setting must be mobilized at considerable cost, including the removal of susceptible HCP from patient contact following VZV exposures (furlough), administration of prophylaxis to patients and HCP, and the time and effort of health care staff in evaluating potential VZV exposures.
Vaccination of susceptible HCP
General approach — Susceptible HCP should be vaccinated against varicella unless there are contraindications (table 1). (See "Vaccination for the prevention of chickenpox (primary varicella infection)", section on 'Contraindications and precautions' and "Vaccination for the prevention of chickenpox (primary varicella infection)", section on 'Special populations'.)
A second dose should be administered four to eight weeks after the first dose. Ideally, all susceptible HCP have completed the vaccine series prior to patient care duties. 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 the injection site). (See 'Varicella' above and "Vaccination for the prevention of chickenpox (primary varicella infection)", section on 'Benefits of immunization'.)
Post-immunization serology is not recommended. Available data suggest that 92 to 99 percent of adults develop antibodies after two doses of varicella vaccine [2], but commercial tests often lack the sensitivity to detect the lower antibody levels associated with vaccination compared with natural infection. Obtaining such screening often leads to confusion and unnecessary re-vaccination.
If the vaccine series was not completed prior to employment, HCP who are in the process of being vaccinated do not require any restrictions in their work activities. Although some HCP may develop vaccine-related varicella after vaccination, the risk of transmitting vaccine strain virus to others is low, and no cases of vaccine virus transmission from recently immunized HCP to susceptible patients have been documented [2,29,30]. However, if a rash does develop, we do implement work restrictions at that time. (See 'HCP who develop vaccine-related rash' below.)
In addition, if an individual is exposed to VZV prior to completing the two-dose series, post-exposure prophylaxis may be indicated to reduce the risk of infection and lessen disease severity in those who become ill. For many, this involves receiving the varicella vaccine within five days of exposure. For immunocompromised or pregnant HCP without evidence of immunity, other types of prophylaxis may be warranted [31,32]. (See 'Post-exposure prophylaxis for HCP without evidence of immunity' below.)
Considerations for persons 50 years of age and older — HCP above the age of 50 who are found to lack varicella immunity should receive the varicella vaccine series, not the recombinant zoster vaccine (RZV). The RZV prevents herpes zoster (shingles) and is not indicated for the prevention of primary varicella infection. The use of RZV in persons who have received the varicella vaccine is discussed separately. (See "Vaccination for the prevention of shingles (herpes zoster) in adults".)
When vaccination should be delayed — Varicella vaccination should be delayed in some settings. As an example, for pregnant HCP, the varicella vaccine should be postponed until after delivery. For HCP who have received immunoglobulin preparation or plasma transfusions, vaccination should be postponed for at least five months from the date of administration.
HCP who develop vaccine-related rash — We furlough or remove HCP from patient care if they develop a vaccine-related rash. They can return to work when all vesicular lesions have fully crusted. If the HCP only developed macules and papules, they can return to work when no new lesions appear within a 24-hour period.
This differs somewhat from CDC recommendations, which state HCP with a vaccine-related rash only need to avoid contact with persons who are without evidence of immunity to varicella and are at risk for severe disease [2]. However, we feel this approach is not always feasible given the difficulty in determining every patient's susceptibility to varicella. (See 'Post-exposure prophylaxis for HCP without evidence of immunity' below.)
Infection prevention measures — The CDC, the American Academy of Pediatrics (AAP), and infectious diseases experts have published guidelines and algorithms designed to aid clinicians in the control of nosocomial exposures [1,33-35]. Our approach is generally in agreement with these guidelines.
Isolation precautions for patients with varicella — Patients with varicella should be placed on airborne and contact precautions [2,36]. A detailed description of these infection prevention 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'.)
Ideally, only HCP with evidence of immunity to varicella should care for patients who have confirmed or suspected varicella. Contact and airborne precautions should be strictly followed, even if the HCP has evidence of immunity, to prevent breakthrough infection. In addition, it is not practical to have different precautions recommendations for different HCP entering the same patient room.
Visitors should be advised that if they lack known immunity to varicella, they should avoid in-person visitation. Some facilities may opt to restrict children if validation of immunization records is not feasible since unvaccinated children are likely not immune. Similarly, since validation of visitor immunity is likely not feasible, all visitors should wear a medical mask or an N95 respirator when in the room.
We are unaware of any nosocomial outbreaks related to infected patients who were placed on airborne precautions. However, one report documented a case of varicella occurring in a susceptible HCP who never entered the patient's negative pressure isolation room but remained in the outside corridor passing materials in through an open door [37]. This incident emphasizes the need for strict observation of airborne precautions [33,36].
Isolation precautions for patients with herpes zoster — As with varicella, it is preferable that only HCP with evidence of immunity to VZV should care for patients who have confirmed or suspected herpes zoster.
●Immunocompetent persons with localized disease – All immunocompetent patients with localized dermatomal zoster require standard precautions [33,36]. A description of standard precautions is presented elsewhere. (See "Infection prevention: Precautions for preventing transmission of infection", section on 'Standard precautions'.)
In addition, the lesion should be kept well covered, if possible. Ideally, this should include a well-fitting gauze bandage covered by a second layer (eg, clothing) or an impermeable bandage.
Our approach is consistent with recommendations from the CDC [20]. Although suspected airborne transmission has been reported from patients with localized zoster [14,15,17,18,38], we support CDC recommendations given the frequency of dermatomal zoster, the high level of immunity among HCP, and the rarity of these events. (See 'Herpes zoster' above.)
●Immunocompromised persons/those with disseminated disease – All patients with disseminated zoster, and moderate to severely immunocompromised patients with localized (dermatomal) zoster, should be placed on airborne and contact precautions [36]. (See "Infection prevention: Precautions for preventing transmission of infection", section on 'Isolation precautions'.)
Persons with moderate to severe immunocompromise include those with cancer receiving chemotherapy, patients receiving CAR-T therapy, hematopoietic cell and solid organ transplant recipients receiving immunosuppressive therapy, persons with advanced or untreated HIV infection, moderate or severe primary immunodeficiency, patients receiving high-dose corticosteroids (ie, ≥20 mg prednisone or equivalent per day for ≥2 weeks), or other agents that are immunosuppressive or immunomodulatory (eg, B cell-depleting agents).
Immunocompromised patients with localized disease can have their airborne precautions removed if, after a period of observation, there is no evidence of dissemination (eg, clinical improvement on therapy).
Considerations for patients without a rash — Some patients presenting with meningitis or encephalitis may be found to have VZV detected in cerebrospinal fluid (CSF) without a rash or evidence of varicella pneumonia. This has been seen more frequently with the increased use of molecular testing to diagnose central nervous system (CNS) infection.
Such patients only require standard precautions. However, careful daily examinations are required to assess for evidence of cutaneous disease since there is a possibility that a rash may develop later. Airborne and contact precautions should be initiated if a rash consistent with varicella is detected.
Susceptible patients exposed to VZV — Hospitalized patients should be tested for serologic evidence of immunity to VZV if they were exposed to a patient with varicella or disseminated zoster, or an immunocompromised patient with localized zoster. Testing should be performed regardless of stated history of varicella infection or vaccination, unless documentation of prior laboratory-confirmed VZV infection or a validated VZV vaccination history (such as from a state vaccination registry) is available.
Susceptible patients should be placed on airborne and contact precautions from the eighth day after the first date of exposure to the 21st day after the last date of exposure [33,34]. A detailed discussion of post-exposure prophylaxis to reduce the risk of varicella infection after an exposure is presented elsewhere. (See "Post-exposure prophylaxis against varicella-zoster virus infection".)
If airborne isolation rooms are not available — Some health care facilities lack adequate airborne infection isolation rooms (AIIR; eg, negative pressure rooms) for patients with varicella or suspected/confirmed disseminated herpes zoster. To meet the Occupational Safety and Health Administration (OSHA) standards, air should be directly exhausted outside with ≥12 air exchanges per hour for new/renovated rooms or ≥6 air exchanges per hour for existing rooms [39].
When this occurs, we prioritize AIIRs for the most contagious patients (ie, those with varicella and disseminated zoster). For others, we employ neutral pressure rooms with portable high-efficiency particulate air (HEPA) units placed between the patient and the door until an AIIR becomes available. HEPA units may reduce the burden of viral particulates within the room, but they do not create negative pressure and thus are not equivalent to an AIIR. In these situations, the door to the room should remain closed except when persons are entering or leaving the room.
MANAGEMENT OF HCP AFTER AN EXPOSURE
Evaluation of exposure — Health care personnel (HCP) should be evaluated by occupational health if they were not wearing recommended personal protective equipment when in contact with a patient with varicella or herpes zoster. (See 'Infection prevention measures' above.)
For HCP without evidence of immunity, the potential for VZV acquisition should be assessed. The risk varies based on the duration and proximity of the exposure, the immune status of the HCP and patient, and the type of disease.
Varicella exposure is generally defined as a susceptible HCP who meets either of the following criteria:
●Did not wear recommended respiratory protection and was within a confined airspace (ie, same room) or had face-to-face contact with a patient with varicella or disseminated zoster. This also includes exposure to a source with localized herpes zoster if the source is moderately to severely immunocompromised and disseminated zoster has not been fully excluded.
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]. In our experience, these situations need to be evaluated on a case-by-case basis rather than strictly based on time.
●Touched vesicular fluid from skin lesions without personal protective equipment. For dermatomal zoster in a normal host, the American Academy of Pediatrics (AAP) defines exposure as contact (eg, touching or hugging) with a person with uncovered, non-crusted lesions [34].
HCP who have direct contact with post-vaccination lesions (a varicella-like rash that typically occurs within three weeks after a varicella vaccine) are not considered exposed unless they themselves (ie, HCP) are immunocompromised. (See "Vaccination for the prevention of chickenpox (primary varicella infection)", section on 'Local and systemic reactions'.)
Management of exposed HCP with evidence of immunity — Exposed health care personnel (HCP) with evidence of immunity to VZV can continue to work, but should be monitored for breakthrough infection from the eighth day after their first exposure to the 21st day after their last unprotected exposure to the person with VZV infection [25]. Criteria for immunity are discussed above. (See 'Establishing susceptibility to infection' above.)
HCP should be monitored daily for fever, skin lesions, and systemic symptoms suggestive of varicella. Breakthrough disease is generally milder than disease in unvaccinated persons, often with fewer than 50 skin lesions. Lesions may be mostly maculopapular with few (or no) vesicles. (See "Vaccination for the prevention of chickenpox (primary varicella infection)", section on 'Breakthrough varicella'.)
HCP can be monitored directly by occupational health or they can be instructed to self-monitor and immediately report any signs or symptoms to occupational health. HCP should be excluded from the health care facility immediately if symptoms and/or signs occur. (See 'Work restriction for HCP with VZV infection' below.)
Post-exposure prophylaxis for HCP without evidence of immunity — Susceptible HCP need post-exposure prophylaxis and may need a work furlough. (See 'Who requires a work furlough' below.)
Post-exposure prophylaxis for HCP typically involves the administration of varicella vaccine, or less commonly, varicella immune globulin (Varizig) or antiviral prophylaxis. The type of prophylaxis depends on whether the individual has any medical contraindication to varicella vaccination (table 1).
The appropriate use of these interventions in HCP is discussed below. Additional information on post-exposure prophylaxis for other persons exposed to VZV is discussed separately. (See "Post-exposure prophylaxis against varicella-zoster virus infection".)
Varicella vaccine — HCP who are not fully vaccinated should receive the varicella vaccine for post-exposure prophylaxis as long as there are no contraindications to vaccination (eg, pregnancy, immunocompromising condition) (table 1) and the HCP is not receiving immunoglobulin therapy or plasma transfusions, which may impact the response. (See 'Vaccination of susceptible HCP' above.)
For most HCP, the vaccine should be administered as soon as possible. An exception is HCP who received their initial varicella vaccine dose less than four weeks prior to the exposure. For such HCP, the second dose of vaccine should be administered four weeks after the first.
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 to five days of exposure [31]. The efficacy of vaccination more than five days after exposure has not been established; however, it should still be administered to protect against subsequent exposures.
Varicella-zoster immune globulin — Varicella-zoster immune globulin (Varizig) is an option for post-exposure prophylaxis in exposed nonimmune HCP who have a contraindication to the varicella vaccine (table 1) and are at high risk of developing varicella complications (eg, persons who are pregnant or immune-compromised) [32]. Ideally, Varizig should be administered as soon as possible after exposure and within 10 days [2,32]. (See "Post-exposure prophylaxis against varicella-zoster virus infection", section on 'Passive immunoprophylaxis'.)
Antiviral therapy — Antiviral prophylaxis (eg, acyclovir, valacyclovir) may be an option for susceptible HCP who cannot receive varicella vaccine or varicella-zoster immune globulin (eg, due to lack of availability, timing, or contraindications). Antiviral therapy should not be used within 14 days of vaccination. Although these agents are not approved for use as post-exposure prophylaxis, the AAP recommend their use when no other alternatives are available [34].
Antiviral prophylaxis should be administered for seven days, beginning seven days after the first date of exposure. Follow-up serologic testing should be performed to determine if the patient has seroconverted, as receipt of antiviral prophylaxis may not eliminate the possibility of future varicella infection [40]. A more detailed discussion of the use of antiviral therapy for the prevention of varicella is presented elsewhere. (See "Post-exposure prophylaxis against varicella-zoster virus infection", section on 'Role of antiviral prophylaxis'.)
Who requires a work furlough — Certain HCP who have been exposed to VZV (as defined above) should be excluded from work from the eighth day after the first exposure through the 21st day after the last exposure [2,20]. (See 'Evaluation of exposure' above.)
These include HCP who:
●Lack evidence of VZV immunity, even if they received their first dose of the varicella vaccine as post-exposure prophylaxis within five days of exposure. (See 'Varicella vaccine' above.)
●Had previously received only a single dose of varicella vaccine and are unable to receive the second dose or received the second dose >5 days after the exposure.
●Received post-exposure prophylaxis with antiviral therapy or Varizig instead of varicella vaccine. Patients who received Varizig should have the furlough extended through the 28th day after the last exposure.
HCP should be monitored for signs and symptoms consistent with varicella (eg, fever, rash) while they are furloughed.
WORK RESTRICTION FOR HCP WITH VZV INFECTION —
All health care personnel (HCP) with VZV infection should be evaluated in an airborne isolation room or via telehealth. Following confirmation of infection, other HCP and patients exposed to the HCP with VZV should be appropriately managed. (See 'Management of HCP after an exposure' above.)
The following HCP should be excluded from work:
●All persons who develop varicella (including breakthrough infection) or disseminated herpes zoster.
●Moderate to severely immunocompromised persons with dermatomal herpes zoster.
●Immunocompetent persons with lesions that cannot be covered (eg, on the hands and face).
●Persons who developed a rash after receiving post-exposure prophylaxis with the varicella vaccine. A rash that occurs in exposed HCP after receiving post-exposure vaccination 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) [41].
(See 'Isolation precautions for patients with herpes zoster' above.)
Such HCP may return to work when clinically well and after all lesions are dried and crusted (usually about five days after symptoms develop). HCP who only have non-vesicular lesions that do not crust should be excluded from work until no new lesions appear within a 24-hour period. This scenario is most likely to occur in individuals with breakthrough infection.
Immunocompetent HCP with dermatomal herpes zoster that is not on exposed areas of the body can continue to work as long as the area is able to be covered with an impermeable dressing and is under clothes. However, these individuals should not care for immunocompromised patients until their skin lesions have become dry and crusted.
SOCIETY GUIDELINE LINKS —
Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Varicella-zoster virus".)
SUMMARY AND RECOMMENDATIONS
●Nosocomial transmission of VZV – Varicella-zoster virus (VZV) is the causative agent of two diseases: varicella (chickenpox), the primary infection, and herpes zoster (shingles), which is due to reactivation of latent VZV infection.
Nosocomial transmission of VZV is well documented from both persons with clinical varicella and with herpes zoster, although the rates of transmission are much higher from patients with varicella. (See 'Transmission of varicella zoster virus' above.)
VZV is transmitted primarily person to person by direct contact with or inhalation of aerosols from vesicular fluid. In persons with varicella, transmission may also occur through contact with infected aerosolized respiratory secretions. (See 'General principles' above.)
●Preventing varicella in the health care setting – Health care personnel (HCP) should be screened for immunity to varicella-zoster. This is typically demonstrated by either written documentation that the HCP received two doses of varicella vaccine or laboratory evidence of immunity. In some cases, documentation of infection by a health care provider is sufficient. All other HCP should be assumed to be susceptible to infection. (See 'Establishing susceptibility to infection' above.)
•Vaccination of susceptible HCP – Susceptible HCP without evidence of immunity should complete the two-dose varicella vaccine series unless there is a medical contraindication to immunization (table 1). Postimmunization serology is not recommended after vaccination. (See 'Vaccination of susceptible HCP' above.)
•Infection prevention measures – Ideally, only immune HCP should care for any patient with VZV infection.
In addition, patients with varicella or disseminated herpes zoster, and immunocompromised patients with localized herpes zoster, require airborne and contact precautions until lesions have crusted. Airborne precautions may be discontinued sooner in selected immunocompromised patients with zoster that remains localized. (See 'Infection prevention measures' above.)
For immunocompetent patients with localized herpes zoster, standard precautions can be used. Although there have been reports of varicella developing in those who have no direct patient contact, suggesting transmission of VZV due to aerosolized virus from skin lesions, these events are rare. (See 'Isolation precautions for patients with herpes zoster' above.)
●Management of exposed HCP – HCP should be evaluated by occupational health if they were not wearing recommended personal protective equipment when in contact with a patient with varicella or herpes zoster.
•HCP with evidence of immunity to VZV – HCP with immunity to VZV do not require any work restrictions but should be monitored for symptoms of infection (ie, breakthrough disease) from the eighth day after their first unprotected exposure through the 21st day after the last exposure. (See 'Management of exposed HCP with evidence of immunity' above.)
•Susceptible HCP – Susceptible HCP exposed to VZV require post-exposure prophylaxis.
HCP should receive the varicella vaccine within three to five days of exposure as long as there are no contraindications to vaccination (table 1). For those without prior vaccination, a second dose should be administered four to eight weeks after the initial dose.
HCP who have contraindications to vaccination should receive varicella-zoster immune globulin (Varizig) if they are at high risk for developing complicated varicella. If Varizig cannot be obtained, antiviral therapy (eg, acyclovir) can be administered from days 7 to 14 after the exposure. (See 'Post-exposure prophylaxis for HCP without evidence of immunity' above.)
Most susceptible HCP exposed to VZV should be excluded from work from the eighth day after their first unprotected exposure through the 21st day after their last exposure (or through the 28th day if they receive Varizig). However, HCP who previously received a single dose of the varicella vaccine can continue working if they receive the second dose within five days of the exposure. (See 'Who requires a work furlough' above.)
●Management of HCP with VZV infection – Management of HCP with VZV infection depends upon the type of disease they develop (eg, varicella versus herpes zoster), their immune status, and whether lesions can be covered. (See 'Work restriction for HCP with VZV infection' above.)
ACKNOWLEDGMENT —
The UpToDate editorial staff acknowledges William A Rutala, PhD, MPH, who contributed to an earlier version of this topic review.
