Chickenpox can be serious in adults, and vaccination should be considered for susceptible individuals. Jane Chiodini explains how to set up a PGD

Varicella (chickenpox) is an acute and highly infectious disease caused by the varicella-zoster virus. Humans are the only reservoir and transmission is direct, by personal contact or droplet spread, and indirect via fomites.1

The incidence of varicella is seasonal, reaching a peak in the UK from March to May.1 It is most common in children below the age of 10 years in whom the disease is usually mild. The secondary infection rate from a case of chickenpox can be as high as 90%, and because it is such a common disease in childhood, 90% of adults are immune.1

The incubation period is between 2 and 3 weeks. Patients are infectious from 1-3 days before the characteristic vesicles appear, and at this stage prodromal symptoms, including fever, malaise, anorexia, headache, cough and sore throat may occur. The rash then usually develops on the scalp and face, spreading to the trunk and abdomen and eventually the limbs. The infectious period continues until the vesicles are dry, and this may be prolonged in immunosuppressed patients.1

Varicella can be more serious in adults, particularly those who smoke, in neonates and in immunosuppressed individuals.1 Complications of primary varicella disease include scarring, pneumonia, haemorrhagic problems, meningoencephalitis, acute transverse myelitis, hemiparesis, osteomyelitis, acute epiglottitis, thrombocytopenia, leucopenia, myocarditis and pyogenic sepsis.2 Varicella kills on average 20 adults each year in England and Wales.3

Maternal chickenpox in the first 20 weeks of pregnancy leads to congenital (fetal) varicella syndrome, which includes limb hypoplasia, microcephaly, cataracts, growth retardation and skin scarring; mortality rates are high. The disease is also severe and even fatal in the neonate a week before to a week after delivery.1

Herpes zoster, or shingles, is caused by reactivation of varicella virus in a patient. This is more common in the elderly but can occur in children and especially the immunosuppressed. Vesicles appear in the dermatome representing cranial or spinal ganglia where the virus has been dormant. The affected area can be intensely painful with associated paraesthesiae.1

Chickenpox vaccine has been available since 1995 in the UK on a named-patient basis and became licensed for use in June 2002. Indications for use include healthy susceptible individuals who are in close contact with immunocompromised patients.

Varicella vaccine should also be considered for any traveller who is susceptible, as confirmed by serological testing where appropriate, especially if he or she is likely to be in close contact with the indigenous population.4

Figure 1: Sample patient group direction for varicella vaccine, Varilrix
Figure 1 (continued): Sample patient group direction for varicella vaccine, Varilrix
Figure 1 (continued): Sample patient group direction for varicella vaccine, Varilrix


Setting up a PGD

Patient group directions (PGDs) have been a legal requirement throughout the UK since 9 August 2000 within the NHS sector. National guidance is now available in England,5 Wales6 and Scotland.7

PGDs should be in place for the administration of these prescription only medicines (POM) to groups of patients who may not be individually identified before presentation at the surgery. Therefore, nurses administering these vaccines must do so only if there is an appropriate PGD in place. To do otherwise, would be to act illegally and could result in a criminal prosecution under the Medicines Act.5-7

It is now more than 2 years since the change in the law and imperative that such documents are in place.

To work in accordance with a PGD, the nurse administering the POM must be named within the document and sign it, as must the senior doctor giving his/her authorisation for the nurse to work within the PGD.

To do this, however, the senior doctor within the practice must be satisfied that this nurse has adequate knowledge and is competent to administer the immunisation in line with the Nursing and Midwifery Council (NMC) Professional Code of Conduct8 and NMC Standards for the Administration of Medicines.9

It is essential to have access to the summary of product characteristics (SPCs) for the vaccines. These are available directly from the drug manufacturers or online at: It is also useful to have all the necessary information to hand before commencing work on a PGD.

The PGD should include:

  • The name of the business to which the direction applies
  • The date the direction comes into force and the date it expires
  • A description of the medicine(s) to which the direction applies
  • Class of health professional who may supply or administer the vaccine
  • Signature of a senior doctor or dentist and a pharmacist
  • Signature of an appropriate health organisation
  • The clinical condition or situation to which the direction applies
  • A description of those patients excluded from treatment under the direction
  • A description of the circumstances in which further advice should be sought from a doctor (or dentist, as appropriate) and arrangements for referral
  • Details of the appropriate dosage and maximum total dosage, quantity, pharmaceutical form and strength, route and frequency of administration and minimum or maximum period over which the medicine should be administered.
  • Relevant warnings including potential side-effects
  • Details of any follow up action necessary and the circumstances
  • A statement of the records to be kept for audit purposes.


  1. Department of Health. Immunisation Against Infectious Disease. London: HMSO, 1996.
  2. Kassianos G. Immunization - Childhood and Travel Health. Oxford: Blackwell Science, 2001.
  3. Rawson H, Crampin A, Noah N. Deaths from chickenpox in England and Wales 1995-7: analysis of routine mortality data. Br Med J 2001; 323: 1091-3.
  4. Zuckerman J. Vaccine-preventable disease. In Zuckerman J (ed). Principles and Practice of Travel Medicine. Chichester: John Wiley & Sons, 2001.
  5. NHS Executive. Patient Group Directions (England Only). HSC 2000/026. Leeds: NHSE, 2000.
  6. The National Welsh Assembly. Review of Prescribing, Supply and Administration of Medicines ¿ Sale, Supply and Administration of Medicines by Health Professionals Under Patient Group Directions (PGD). COCNOCDOC SOCPhA-SALEMED3. 22 December 2000.
  7. Scottish Executive Health Department. NHS HDL (2001)7. Patient Group Directions. January 2001.
  8. Nursing and Midwifery Council. Code of Professional Conduct. London: NMC, 2002.
  9. Nursing and Midwifery Council. Standards for the Administration of Medicines. London: NMC, 2002.

Guidelines in Practice, February 2003, Volume 6(2)
© 2003 MGP Ltd
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