Case 7: paediatric infection control
You were informed by one of the patient service managers that one of her staff (a 26 year-old female) has just been diagnosed by her family practitioner as having chicken pox. She works on the general paediatric ward and her last day of work was three days ago, the same day the rash developed. The nurse had worked with three patients in adjacent rooms for five days prior to her last day of work, although she had been giving break relief to other nurses throughout that period. The unit has twelve patients on the one wing. The children range from age 2 to 13.
Case Seven Questions:
1. What precautions should be taken, if any, to protect patients on the ward? Would you recommend prophylactic therapy for any of the patients? Justify your response
Seeing as the nurse diagnosed with chicken pox has potentially been in contact with all patients on the ward through covering break relief as well as caring for the own patients it would be a sensible to test all twelve of the patients for their Varicella IgG antibody titer to determine immune status to chicken pox (Lautenbach, p. 293).
Children without immunity should be immunized as per BCCDC guidleines. Children who cannot be immunized as a result of the following should be closely monitored:
- “a life-threatening reaction to a previous dose of chickenpox vaccine, or any component of the vaccine including neomycin or gelatin
- an immune system weakened by disease or medical treatment;
- a blood transfusion or received other blood products within the past 12 months;
- active untreated tuberculosis” (HealthlinkBC, 2017)
Considering that we do not yet know if the nurse was infected by a patient at work it would be advisable to put all patients on airborne precautions to prevent possible further spread from one patient to others until lab results come back (Lautenbach, p.301).
Noting that children routinely receive their first dose of the chicken pox vacine at age 12 months and the second and final dose between the ages of 4 and 6 years (BCCDC, 2017) the patients on the pediatric unit who have not received the varicella vaccine at all or those who have not yet completed their second dose of the vaccine are especially at risk and should be monitored closely for symtoms.
The incubation period for Varicella Zoster is 14-16 days with a range of 10-21 days) and up to 28 days in persons who have received the VZIG (Lautenbach, p 293).
Infected individuals are infectious 1-2 days before and shortly after rash appears which was when the nurse was working prior to developing a rash.
Until lab results return on our 12 patient’s immune titres for varicella zoster it is best to treat all patients is nonimmune. “nonimmune patients who have been exposed to chicken pox should be placed under airborne precautions from day 10 through day 21 after their initial exposure (or through day 28, if the person is immunocompromized or received varicella zoster immunoglobulin)” (Lautenbach, p. 301)
Therefore, patients should remain on airborne precautions for 21 days unless they hae received the VZIG, then should remain on precautions for 28 days.
Would prophylactic therapy be recommended? Varicella zoster can cause “severe morbidity and mortality…in immunocompromized individuals” (Gnann, 2007). The virus is also associated with a “much greater mortality in patients with impaired cell-mediated immune response ” (Gnann, 2007). Therefore if these criteria fit any of the 12 pediatric patients their exposure could have dire consequences. “The outcomes of varicella and herpes zoster, especially in immunocompromised patients have been dramatically improved by safe and effective antiviral drugs” (Gnann, 2007).
In immunocompromized pediatric patients with varicella zoster, IV acyclovir reduced the frequency of VZV pneumonitis from 27% down to zero (Gnann, 2007).
In our exposed patients close monitoring and IV acyclovir intiated at the first sign of infection, switching to oral antiviral therapy when the patient is afebrile and no new lesions have appeared. (Gnann, 2007)
Lautenbach, p. 293 states for prophylaxis of “non-immune immunocompromised persons, consider giving VZIG within 96 hours after exposure.
If lesions develop the patient(s) should be placed on both airborne and contact precautions. The varicella zoster or disseminated zoster virus and shingles may be spread through:
- “face-to-face contact with infected person for 5 minutes of more without wearing a respirator,
- direct contact with vesicle fluid without wearing gloves,
- continueous household contact
- direct contact with vesicle fluid without wearing gloves” (Lautenback p. 293)
2. What, if any, infection control measures should be considered for the hospital workers?
Health care workers in theory should have been vaccinated at or prior to employment however based on the fact that our 26 year old pediatric nurse has just developed varicella zoster we cannot assume any of the workers have their Varicella vacinations. I would start by obtaining the vaccination status of all the hospital workers for varicella. Lautenbach, p. 293 states for “susceptible HCW, consider giving Varicella virus vaccine within 3 days after exposure to prevent or modify infection, giving the vcaccine does not change the work restirctions”.
So far as infection control measures relating to Varicella zoster exposed healthcare workers are at risk of infection unless the worker has serologic evidence of immunity or has documentation of recieving 2 doses of the varicella vaccine (Lautenbach, p. 293). For those without immunity to varicella zoster work restritcitons after exposure are as follows:
- Day 1-7, no restrictions
- Day 8 of first (or single ) exposure through day 21 of last exposure the healthcare workers “must not work or must not have direct patient contact and must work only with immune persons away from patient-care areas” (Lautenbach, p. 293).
- For health care workers who receive VZIG work is restricted through day 28.
- Infected healthcare workers may return to work after lesions are dry and crusts.
3. What are the tests available to confirm a diagnosis of chicken pox? Is laboratory confirmation always necessary – why or why not?
Varicella zoster is confirmed by:
- “isolation of the varicella virus from an appropriate clinical lab specimen
- significant rise in serum varicella varicella IgG antibody by any significant serological assay
- presence of clinical illness in any person who is epidemiologically linked to a confirmed case.
- Note: a clinical illness is characterized by rash with rapid evolution of macules to papules to vesicles to crusts with all stages simultansiously present. Lesions are superficial and may appear is crops.” (BCCDC, 2004)
Given that Varicella zoster cases can be confirmed in persons with presence of illness who are epidemiologically liked to confirmed cases, laboratory confirmation is not always necessary.
4. How effective is Varicella zoster vaccination in children? In adults? What are the potential complications?
A long term pediatric study of the vaccine effectiveness found the vaccine to be 90% effective (Baxter et al, 2013). ). The Baxter et al. study found that cases that did develop occurred early after the first dose of vaccine, symptoms were mild. They found that no child developed Varicella after the second and final dose of the vaccine. (Baxter et al, 2013).
However BCCDC states “The efficacy of a single dose of varicella-containing vaccine is about 94% in children. With a second dose, efficacy is about 98%.” (BCCDC, 2017).
“In healthy children 12 months to 12 years of age, a single univalent varicella vaccine dose results in a seroconversion rate of 98% at 4 to 6 weeks after vaccination, with antibodies persisting in 98% at 5 years and 96% at 7 years after vaccination. A second dose of a univalent varicella vaccine in children produces an improved immunologic response that is correlated with improved protection.” (Canadian immunization guide, p. 24)
“In adults and adolescents 13 years of age and older, 2 vaccine doses administered 4 to 8 weeks apart result in seroconversion rates of 99% at 4 to 6 weeks after the second dose, with persistence of antibodies 5 years later in 97% of vaccine recipients.”(Canadian immunization guide, p.24).
“The estimated vaccine effectiveness 10 years following the receipt of 2 doses of univalent varicella vaccine is estimated at over 98% against any varicella disease and 100% against severe varicella.” (Canadian immunization guide, p.24).
In older adults aged 60 or over the shingles vaccine is recommended to prevent recurrence of shingles as the immune system weakens with age. “however anyone 50 years of age and older can get the vaccine. Only 1 dose is needed for protection.” (Healthlink BC: Shingles vaccine)
Possible complications and side effects: “Reactions to univalent varicella vaccine are generally mild and include injection site pain, swelling and redness in 10% to 20% of recipients. A low-grade fever has been documented in 10% to 15% of vaccine recipients. A varicella-like rash occurs at the injection site or is generalized in 3% to 5% of vaccine recipients after the first dose. The rash usually appears within 5 to 26 days after immunization. As varicella-like rashes that occur within the first 2 weeks after immunization may be caused by wild-type virus (varicella virus circulating in the community” (Canadian immunization guide)
5. This nurse, as the case turns out, is pregnant and delivers the day following her visit to her family practitioner. The baby is admitted to the neonatal intensive care unit. What measures should be taken?
Measures to be taken for the infected nurse:
“Persons are contagious from 5 days (but usually 1 to 2 days) before onset of rash until all lesions have crusted.” (BCCDC, 2004) so contact precautions are necessary during care.
The nurse is at high risk for complications of Varicella zoster due to the fact that she became infected while preganant as has now just delivered (BCCDC, p.4). Our next step to protect this high risk patient is to “provide immunoprophylaxis with either Varicella Zoster Immune Globulin (VZIG) or varicella vaccine.”
Measures to be taken for the infant:
Lab tests to determine if the infant has contracted varicella zoster. In this case the infant is epidemiologically linked to a confirmed case through the mother, however isolating the virus in the infant from an appropriate clinical specimen or testing “Significant rise in serum varicella IgG antibody level by any standard serologic assay” (BCCDC, p.2) will help guide treatment.
Page two of BCCDC Varicella zoster guideline states “Children exposed to varicella-zoster virus in utero during the second 20 weeks of pregnancy can develop inapparent varicella and subsequent zoster early in life without having had extrauterine varicella.” so continued monitoring will be necessary.
“Varicella infection can be fatal for an infant if the mother develops varicella from 5 days before to 2 days after delivery.” (BCCDC, p2) in our case the mother contracted Varicella zoster, developing a rash 5 days before delivery placing the infant in this high risk category.
Considering that the vaccine is offered to children 12 months of age or older, this infant is not elligible(BCCDC, 2017). “Varicella zoster immune globulin (VZIG) given within 96 hours of exposure may prevent or modify disease in susceptible close contacts of cases.” (BCCDC, 2004). Our infant fits into the timeline criteria to be given VZIG for management of this viral infection as the infant is a newborn whose mother developed varicella disease 5 days before delivery. (BCCDC, 2004).
The newborne should be on contact and airborne precautions while in treatment in NICU (Lautenbach, 2010)
1. BCCDC. 2017. Chicken pox (Varicella) Vaccine. Accessed April 3, 2017 from http://www.bccdc.ca/health-info/immunization-vaccines/vaccines-in-bc/chickenpox-varicella-vaccine
2. Healthlink BC. 2017. Chicken pox (Varicella) Vaccine. Accessed April 3, 2017 from https://www.healthlinkbc.ca/healthlinkbc-files/chickenpox-vaccine
3. Lautenbach, E., Woeltje, K., and Malani, P. 2010. Practical HealthcareEpidemiology, 3rd ed.
4. Gnann, Jr, JW. 2007. Antiviral Therapy of Varicella-zoster virus infections. Human Herpesviruses: Biology, Therapy, and Immunoprophylaxis. Accessed April 3, 2017 from https://www.ncbi.nlm.nih.gov/books/NBK47401/
5. BCCDC. 2004. Communicable disease control Varicella zoster. Accessed April 5, 2017 from http://www.bccdc.ca/resource-gallery/Documents/Guidelines%20and%20Forms/Guidelines%20and%20Manuals/Epid/CD%20Manual/Chapter%201%20-%20CDC/Epid_GF_VaricellaZoster_July04.pdf
6. Baxter, R, Ray, P, and Tran, T et al. 2013. Long term effectivenss of Varicella vaccine: a 14-year prospective cohort study. Pediatrics. Vol 131, Issue 5 accessed April 6, 2017 from http://pediatrics.aappublications.org/content/131/5/e1389.short
7. Government of Canada. 2016. Canadian Immunization guide. Accessed April 6, 2017 from https://www.canada.ca/en/public-health/services/publications/healthy-living/canadian-immunization-guide-part-4-active-vaccines/page-24-varicella-chickenpox-vaccine.html#p4c23a4
8. HealthlinkBC> 2017. Shingles Vaccine. Accessed April 6, 2017 from https://www.healthlinkbc.ca/healthlinkbc-files/shingles-vaccine