Identification of potential candidates for varicella vaccination by history: questionnaire and seroprevalence study

Introduction

Guidance from the Joint Committee on Vaccination and Immunisation regarding varicella vaccination of workers in healthcare settings is imminent.1 The new recommendations will advise that all those with a negative or uncertain history of chickenpox or shingles at pre-employment assessment should be tested for varicella zoster virus IgG. Vaccination with the newly licensed varicella vaccine will be advised for those with a seronegative result.

A history of chickenpox has a high positive predictive value for immunity among healthcare workers in Europe, where the seroprevalence is as high as 98.5%.2 The validity of a history of chickenpox is unknown in those from tropical countries, however, where the mean age of infection is in early adulthood.3 Guy's and St Thomas' Hospital NHS Trust in inner London has some 8000 staff and 4700 healthcare students of increasingly heterogeneous origins.4 5 We conducted a questionnaire and seroprevalence study at the hospital to ascertain the relations between history of chickenpox, countries …