Management of Varicella-Zoster exposure in hospital settings
By Dr.Sarah Alsubaie
Assistant professor of pediatrics, consultant pediatric infectious diseases and infection control
Varicella (chickenpox) is an acute, generalized viral disease with sudden onset of fever and vesicular skin eruptions. Lesions tend to be more abundant on covered than on exposed parts of the body.
The virus establishes latency in the dorsal root ganglia during primary infection (varicella). Reactivation results in herpes Zoster (shingles).
Although varicella is usually a benign childhood disease and rarely rated as an important public health problem, it is one of the most readily communicable diseases, especially in the early stages of eruptions. Zoster has a lower rate of transmission unless it is disseminated which usually occur in immunocompromised patients. Varicella seronegative contacts of herpes zoster patients can develop chickenpox. Infection tends to be more sever in adult and adolescents than in young children. Infection with varicella zoster virus may be complicated by pneumonia (especially adults), central nervous system involvement (encephalitis, acute cerebellar ataxia) sometimes with persistent sequelae or death. Secondary bacterial infections of the vesicles may result in necrotizing fasciitis or septicemia or leave disfiguring scars. Other rare complications include glomerulonephritis, arthritis and hepatitis. Reye syndrome can follow cases of chickenpox although its incidence has decreased with decreased use of salicylate during varicella or influenza-like illnesses.
Varicella – zoster virus (VZV) is a member of the herpes virus family. Humans are the only source of infection for this highly contagious virus.
By the airborn route: infection can be acquired when the virus comes in contact with the mucosa of the upper respiratory tract or the conjunctiva.
By the contact route: direct skin to skin contact with vesicular fluid from patients with varicella or zoster lesions.
Nosoconmial transmission is well documented. Several outbreaks in hospitals and other institutional settings have been reported. Sources for nosocomial exposures have included patients, healthcare personnel, and visitors with either varicella or herpes zoster. Exposure and transmission typically associated with hospital areas that have no negative pressure isolation rooms, such as emergency rooms, radiology units, outpatient waiting areas, preoperative and post operative holding rooms. Transmission may occur before lesions develop when patient not in appropriate negative pressure isolation room.
Asymptomatic primary infection is unusual, but because some cases are mild, they may not be recognized. Occasionally, especially in adult, the fever and constitutional manifestations may be severe.
Immunocompromised people with primary (varicella) or recurrent (zoster) infection are at increased risk of sever disease. The groups of patients who may experience complicated disease \include premature babies, infants, adolescents, pregnant women, cancer patients, immunodeficiency including HIV infection, patients with chronic cutaneous or pulmonary disorders, and patients receiving systemic corticosteroids or long-term salicylate therapy.
In utero infection can occur as a result of transplacental passage of virus during maternal varicella infection. If a pregnant woman acquires varicella infection during the first half of pregnancy the fetus will be at risk for developing congenital varicella syndrome. Varicella can develop in the first 3 weeks of life in infants born to mothers with active varicella around the time of delivery (5 days before or 2 days after delivery). If the neonate become infected it may result in a sever varicella with fatality rate as high as 30%. When Varicella develops in a mother more than 5 days before delivery and gestational age is 28 weeks or more, the severity of the disease in the newborn infant is modified by transplcental transfer of VZV-specific maternal immunoglobulin (Ig) G antibody.
Infection confers long life immunity; second attacks are rare in immunocompetent persons but have been documented.
The incubation period usually is 14-16 days and occasionally is as short as 10 or as long as 21 days after contact. It may be prolonged for as long as 28 days after receipt of varicella- Zoster Immue Globulin (VarZIG) or Immune Globuline Intravenous (IVIG) and shortened in immunocompromised patients.
Period of communicability:
Patients are most contagious from 1-2 days before to shortly after the onset of rash. Contagiousness persists until crusting of all lesions (usually about 5 days) and is more prolonged in patients with altered immunity. Susceptible individuals should be considered infectious for 10-21 days following exposure.
Hospital exposure: Defined as:
Varicella: 1) patients in the same 2- to 4- bed room or adjacent beds in a large ward
2) Face to face contact with an infectious staff member or patient (for 5 or more minutes)
3) Visit by a person deemed contagious
Zoster: Intimate contact (e.g. touching or hugging) with a person deemed contagious (with exposed zoster lesion).
Newborn infant: onset of varicella in the mother 5 days or less before delivery or within 48 h after delivery.
Control measures if an inadvertent exposure in the hospital to an infected patient occurs:
Immediately notify infection control department.
Identify personnel and patients who have been exposed and are susceptible to varicella
All exposed susceptible patients who are fit for discharge should go home as soon as possible.
All exposed susceptible patients who can't be discharged should be placed in contact and airborn isolation room from day 10 to day 21 after exposure. For people who have received varicella zoster immunoglobulin (VZIG), isolation should be continued until day 28.
Staff who are nonimmune or whose status is unknown must be evaluated by employee health clinic immediately. If staff is immune no further action will be taken. If found to be non-immune, he/ she can be offered varicella vaccine if still within 3 days of exposure, if ineligible for immunization he/she must remain off work from days 10-21 postexposure.
Susceptible people at high risk of developing severe varicella should be given Varicella zoster immunoglobulin (VZIG) within 4days of exposure, if not available, intravenous immunoglobulin (IVIG) is recommended.
- Indication for varicella zoster immunoglobulins:
1) Immunocompromised patients without history of varicella or varicella immunization.
2) Susceptible pregnant women. (there is no assurance that VZIG will prevent congenital malformations in the fetus, but it may modify varicella severity in the pregnant women).
3) Newborn infant whose mother had onset of chickenpox within 5 days before or 2 days after delivery.
4) Hospitalized premature infants ≥ 28 wks of gestation whose mother lacks a reliable history of chickenpox or serologic evidence of protection against varicella.
5) Hospitalized premature infants <28 wk of gestation or ≤1000g birth weight, regardless of maternal history of varicella or serology result.
- Whether the uninfected newborn of a mother with peripartum varicella should be separated from the mother remains controversial. The AAP (American Academy of Pediatrics) recommends that the neonate who has been given VZIG may remain with the mother. Some physician may choose to separate infant from mother until all of maternal lesion have crusted. Rationale for separation is that the infant may not have been infected in utero and can acquire varicella from the mother during postnatal period.
- Post exposure varicella vaccine: administration of varicella vaccine to susceptible contacts within 3 days of exposure may prevent or significantly modify disease. There is no evidence that administration of varicella vaccine during the presymptomatic or prodromal stage of illness increases the risk of vaccine associated adverse events or more sever natural disease.
Routine varicella immunization is now recommended by ACIP (Advisory committee on immunization practices) for all non-immune health care workers. Serologic testing for immunity in vaccine receipient is not necessary because 99% of adults are seropositive after the second vaccine dose.
- Chemoprophylaxis with oral acyclovir generally is not recommended for immunocompetent individuals. It can be considered for a susceptible immunocompromised patient who has been exposed to varicella and VZIG is not available or more than 96 hrs have passed since exposure.
1) American academy of pediatrics. Varicella-zoster infections. 2006 Red book: report of the committee on infectious diseases. 27th edition.
2) Association for Professionals in Infection Control (APIC) Text of Infection Control and Epidemiology. 2002;109:18-21
3) Center for disease control and prevention: Prevention of varicella. MMWR 1999; 481-6.
4) Mayhall: Hospital epidemiology and Infection control., third ed. Lippincott Williams & Wilkins: Philadelphia, 2004, Chapter 51:836-838