The Varicella Zoster virus reference service (VZRS) is affiliated to the Virus Reference Department (VRD) at Health Protection Agency (HPA.)Centre for Infections (C4I) Colindale. The VZRS is based at Barts and the London Hospital Trust (BLT) and is headed by Professor Judy Breuer (see below for contact details for samples and advice).

Varicella zoster virus is the cause of the common childhood infection, chickenpox (varicella). Following primary infection, the virus lies dormant in the sensory neural ganglia, reactivating in about 25% of the population to cause the painful dermatomal rash, shingles (Herpes zoster). Both chickenpox and shingles increase in severity with age. Chickenpox is x time more likely to cause complications in adults aged over 20 years than in children. Shingles is 20 times more likely to cause severe persistent pain in subjects over the age of 60 years than in those aged under 50 years. Both diseases can be life threatening in subjects with impaired immune systems i.e. those who are HIV positive, are receiving immunosuppressive drugs including steroids and those who have undergone organ or bone marrow transplantation. In addition chickenpox may be more severe in pregnant women as well as posing a risk of congenital infection in the foetus early pregnancy and neonatal infection if the mother becomes infected in late pregnancy. Information about the prevention and management of patient groups who may be at risk of severe chickenpox infection is outlined in Chapter 34 of the Green Book on immunisations etc etc.

A live attenuated vaccine, the Oka strain, is available for prevention of chickenpox in health care workers in the UK. A leaflet detailing the benefits of and contraindications to vaccination can be downloaded from this site (http://www.clinical-virology.org/pages/vzrl/Vaccine_information_sheet.pdf). Ninety five percent of adults seroconvert following two does of Oka vaccine. However, some fail to produce antibody and may need additional vaccine boosters. Commercial tests in use in most UK microbiology and virology laboratories are not always sensitive enough to detect post vaccination antibody. The VZRF has developed reference antibody tests which are up to 50 times more sensitive than available commercial assays.

The vaccine is extremely safe, with fewer complications than natural infection with chickenpox. In about 5-10% of individuals a rash may develop post vaccination. It is important to determine whether this is due to the vaccine strain or to coincidental chickenpox. The reference laboratory has developed molecular tests which can distinguish between the vaccine strain of varicella zoster virus and the ordinary strains circulating in the UK.

Test Description	Specimen required	NHS Price	Turnaround Time (Days)
VZV Serology Ref lab (Latex, EIA, TRFIA)	Serum	£11.25/£17.26/£14.97	10
VZV Quantitative PCR	EDTA Blood/CSF	£35.00	14
VZV Genotyping	Isolate (primary swabs in VTM or saline may be sent by arrangement only) AND/OR DNA	£60.00	14
VZV Phenotypic Resistance	Isolate (primary swabs in VTM may be sent by arrangement only)	£35.00	28
NB. Commercial prices available on request.

Please see algorithm

Please complete request form sections A, B and C

Pre vaccine immunity status
Detection of antibody by the reference TRFIA test in staff with negative and equivocal pre-vaccination serology
Sample: serum

Post vaccination immunity status
Detection of antibody by reference TRFIA test in staff who, post-vaccination, remain seronegative by commercial tests.
Sample: serum

VZV IgG Avidity
For diagnosis of primary/recurrent infection by IgG avidity.
For diagnosis of recent infection in pregnancy.
Sample: serum

Please complete request form sections A, B and C

Typing of post vaccine rashes
Differentiation of vaccine and wild type virus in rashes occurring (<42 days post vaccination.
Also breakthrough infection (varicella-like rash occurring >42 days post immunisation) and zoster occurring in Oka vaccinees
Instructions as to how to take the samples are available at (web link)
Sample: scraping/swab of vesicle(s) in saline/Viral Transport Medium) – see web link for details

Investigation of systemic complications following vaccination
Please ring the laboratory to discuss investigations necessary

VZV typing

Genotying of virus from outbreaks and transmission events
Please complete form section A and C

Sample :
VZV viral isolate or
VZV viral DNA or
Swab/scraping from lesion in saline or viral transport medium (VTM)
(instructions for taking sample available at http://www.clinical-virology.org/pages/vzrl/skin_lesions.pdf)

VZV resistance testing

Please complete form section A and C

Sample :
VZV isolate and/or
VZV DNA, or
Swab/scraping from lesion in saline or viral transport medium (VTM)
(instructions for taking sample available at http://www.clinical-virology.org/pages/vzrl/skin_lesions.pdf)


VZV viral load monitoring/DNA detection by realtime PCR

In blood, CSF etc from difficult cases which fail to respond to treatment
Please complete form section A and C

Sample:
EDTA blood
Other fluids in sterile container
In vesicle fluid, CSF, joint fluid, BAL;
Swab/scraping from lesion in saline or viral transport medium (VTM)
(instructions for taking sample available at http://www.clinical-virology.org/pages/vzrl/skin_lesions.pdf)

VZRS
Department of Virology
51-53 Bartholomew close
London

Hays Dx 6640602 (Barbican 90EC)

General Enquiries (0207 601 7353)
Peter Wriede (peter.wriede@bartsandthelondon.nhs.uk)
Tony Oliver (tony.oliver@bartsandthelondon.nhs.uk)
Judy Breuer (j.breuer@qmul.ac.uk)


Clinical Enquiries (0207 601 7353)
Barts and the London
Professor Judy Breuer (j.breuer@qmul.ac.uk)
Dr Ines Ushiro-Lumb (ines.ushiro@bartsandthelondon.nhs.uk)
Dr Frank Mattes (frank.mattes@bartsandthelondon.nhs.uk)
Dr Duncan Clark (duncan.clark@bartsandthelondon.nhs.uk)
HPA Colindale
Professor David Brown (david.brown@hpa.org.uk)
Professor Elizabeth Miller (liz.miller@jpa.org.uk)

Rash occurring within 42 days of varicella vaccination (vaccine associated rash)
OR
Rash occurring in subject who has received vaccine more than 42 days previously (breakthrough infection)
OR
Herpes zoster occurring in a subject who has received the varicella vaccine.



Take sample of rash using dry sterile swab
(http://www.clinical-virology.org/pages/vzrl/skin_lesions.pdf)

Break swab into 1 ml saline or viral transport fluid (VTM) (if available)



Download and complete HPA forms B and C for vaccine-related rash from website (http://www.clinical-virology.org/pages/vzrl/VZRL_request_form.pdf)



Send form and sample to Department of Virology and Microbiology
Barts and the London
Hays DX no 6640602 (Barbican 90EC)



Inform the laboratory 0207 601 7353 that samples are coming

For further information telephone:
Professor Breuer 0207 882 2308
Dr Chris Maple 0207 601 7353
Tony Oliver 0207 601 7353
Dr Duncan Clark 0207 601 7355

Health care worker post vaccination
Does HCW work with high risk patients Paediatrics, Obstetric, Oncology, HIV positive, immunosuppressed	No	No need for post -vaccination serology
Yes
Test for VZV antibodies in local laboratory		Positive No further serology
Negative
Send to VZRS for reference serology

NB. Adobe Acrobat Reader is required to read pdf files.If you don't have a copy of Adobe Acrobat Reader it can be downloaded by following the link below.