Public Health Agency

Varicella-zoster Virus


Chicken pox and shingles are caused by the same herpes virus (varicella-zoster virus).

Primary Infection: Chicken Pox

Virus is present in respiratory secretions as well as in the vesicle fluid. Respiratory tract secretions are a potent source of airborne infection making patients highly infectious from approximately 48 hours before the rash occurs until all the vesicles have dried and crusted (usually about 6 days).

Secondary (Reactivated) Infection: Herpes Zoster (Shingles)

Shingles only occurs in patients who have previously had chickenpox. The virus reactivates in sensory nerve cells and erupts in the cutaneous distribution of the nerve. Systemic dissemination may occur in immunosuppressed patients. The varicella-zoster virus can lie dormant for decades without causing any symptoms. In some people, the virus reactivates and travels along nerve fibres to the skin; the result is a distinctive, painful rash called shingles.

Contacts of shingles who have not had chickenpox are at risk but they will develop symptoms of chickenpox not shingles. Virus is present in the vesicle fluid until the vesicles have dried. However, respiratory secretions are not usually a source of infection in shingles except in those with oro-facial (trigeminal) disease. Immunosuppressed patients (e.g. Hodgkins Disease) may have prolonged illness with infectious virus excretion and may require isolation for a longer period.



  • Patients with chicken pox should be transferred to a negative pressure ventilation isolation room. If not available, Source Isolate in a side room with the door closed
  • Patients with shingles, especially with trigeminal distribution should be nursed in source isolation. If disseminated or localised infection occurs in an immunocompromised patient they should be nurse with airborne and contact precautions; if localised in non-immunocompromised patients they should be nurse with contact precautions only until all lesions are dry and crusted over
  • Public Health Agency should be informed

If a case of chickenpox has been cared for on the open ward prior to diagnosis of the infection, the following actions should be undertaken:

Patient contacts

  • Ward/ facility staff should draw up a list of patient contacts and inform the Infection Prevention Control Team
  • Patients on the contact list should be checked for immunity, firstly by taking a history from the patient or relatives (patients with a convincing history of having had chickenpox can be considered immune without antibody testing) and, if necessary, by testing for antibody
  • The consultant caring for patient contacts, found to be non-immune, will agree ongoing management and treatment with a consultant virologist or microbiologist. The decision to dispense VZIG and/or live vaccine must be taken in discussion with the consultant virologist in the Royal hospitals, BHSCT
  • The following groups are considered to be at increased risk from varicella and may require passive immunisation with Varicella Zoster Immunoglobulin (VZIG):

-       pregnant women

-        neonates

-        immunocompromised individuals including those on steroids, chemotherapy

-        HIV positive

-        haematological malignancy


  • Ward/ facility manager should draw up a list of staff contacts and inform the Occupational Health Department (OHD)
  • OHD should follow up staff contacts not known to be immune by arranging for an antibody test
  • If susceptible, staff may be excluded from working in wards where there are vulnerable patients between day 8 after first contact and day 21 after last contact
  • If a non-immune staff contact becomes ill within the incubation period of the disease (i.e. up to 21 days after last exposure) with even a trivial cold or fever, they should report to the OHD. Non-immune staff in contact with these diseases must not transfer to other wards or nurse immunosuppressed patients during the incubation period
  • The decision to dispense VZIG and/or live vaccine must be taken in discussion with the consultant virologist in the Royal hospitals, BHSCT
  • Serologically negative staff may be offered vaccination
  • Staff must know their immune status. Non immune staff who have been exposed to varicella outside of work should inform their line manager and immediately consult with occupational health department regarding their fitness to practice

Varicella-zoster Immune Globulin (VZIG) is available for high risk individuals who have been exposed to chickenpox or shingles. It will attenuate, not prevent, infection. It is only effective when given within 7-10days of exposure and is usually reserved for those not immune to varicella-zoster in whom the disease may be life threatening. Decisions as to whether to administer VZIG is the responsibility of a Virologist.


1.     Immunisation Against Infectious Disease 2006 ‘The Green book’ chapter 34. Available from:

2.     Chickenpox: public health management and guidance (2014). Available at: