Screening healthcare workers for varicella-zoster virus: can we trust the history?
OBJECTIVE
To determine the relationship between immunity and a history of chickenpox based on a self-administered questionnaire.


METHODS
We investigated immunity to varicella-zoster virus in a cohort of newly recruited employees with different job categories and different nationalities using enzyme-linked immunosorbent assay IgG.


RESULTS
There were 1,058 new recruits. Of these, 890 (84%) were immune and 168 (16%) were susceptible. The susceptibility rate was 23% (n = 77) for Asian, 15% (n = 14) for South African, 13% (n = 66) for Middle Eastern, and 9% (n = 11) for Western employees. Physicians were more likely to be immune (93%) than were nurses (85%), medical technicians (75%), or administrative clerks (84%). Seropositivity was not affected by age or gender. The positive predictive value of a history of chickenpox for the seropositivity was 89% (511 of 574); the negative predictive value was 22% (105 of 484). History of chickenpox had a sensitivity of 57% (511 of 890) and a specificity of 63% (105 of 168).


CONCLUSIONS
The varicella-zoster virus seroprevalence among new employees was low, posing an important risk to existing employees and patients. Positive or negative history of chickenpox was an unreliable indicator of susceptibility among healthcare workers of different nationalities. Serologic screening of all employees and vaccination of those susceptible was recommended.
Department of Infection Prevention and Control and Pediatrics, King Abdulaziz Medical City-King Fahad National Guard Hospital, Riyadh, Kingdom of Saudi Arabia.
Maha
M
Almuneef
Ziad A
ZA
Memish
Mostafa E
ME
Abbas
Hanan H
HH
Balkhy
D000328:Adult; D000914:Antibodies, Viral / Q000097:blood*; D002644:Chickenpox / Q000175:diagnosis / Q000453:epidemiology / Q000276:immunology*; D015331:Cohort Studies; D004196:Disease Outbreaks / Q000517:prevention & control; D005006:Ethnicity / Q000706:statistics & numerical data; D005260:Female; D006282:Health Personnel / Q000706:statistics & numerical data*; D014645:Herpesvirus 3, Human / Q000276:immunology*; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods / Q000706:statistics & numerical data*; D008487:Medical History Taking / Q000706:statistics & numerical data*; D008875:Middle Aged; D011237:Predictive Value of Tests; D012529:Saudi Arabia / Q000453:epidemiology; D016036:Seroepidemiologic Studies; D014611:Vaccination / Q000706:statistics & numerical data
D000914:Antibodies, Viral