High rate of varicella complications among Mexican-born adults in Alabama.
OBJECTIVE
Our study examines risk factors for severe varicella in an outbreak among Mexican-born adults, and it compares susceptibility to infection and reliability of self-reported varicella history for these individuals with that for adults born in the United States in the outbreak locale, which may guide vaccination strategies.


METHODS
We interviewed case patients and non-case persons in the affected apartment complex and workplace, assessed disease history and susceptibility by testing for varicella-zoster virus immunoglobulin G antibodies, and reviewed the clinical data of case patients.


RESULTS
Five of 18 case patients had serious complications for which they sought medical care; 1 was hospitalized for pneumonia, and 1 was hospitalized for Guillain-Barré syndrome. Only intense exposure (e.g., sharing a bed) was marginally associated with severe disease (P=.08). In the workplace, varicella susceptibility was higher among Mexican-born workers (20%) than among workers born in the United States (3%) (adjusted prevalence odds ratio, 5.4; 95% confidence interval, 2.3-14.8). Mexican-born persons had the highest positive predictive value of self-reported disease (100%) in predicting immunity, and those born in the United States had the lowest negative predictive value of self-reported history (10%) in predicting susceptibility.


CONCLUSIONS
Varicella is a more serious disease among adults than among children, and Mexican-born adults living in the United States might have a higher risk of acquiring varicella than US-born adults. Varicella outbreaks involving adults should be prioritized for control efforts. Outbreaks can be prevented by vaccinating susceptible adults.
Danovaro-Holliday
M Carolina
MC
National Immunization Program, Centers for Disease Control and Prevention, Atlanta, GA, USA. danovarc@paho.org
Gordon
Ely R
ER
Jumaan
Aisha O
AO
Woernle
Charles
C
Judy
Randa H
RH
Schmid
D Scott
DS
Seward
Jane F
JF
D000293:Adolescent; D000328:Adult; D000407:Alabama / Q000453:epidemiology; D002644:Chickenpox / Q000150:complications* / Q000453:epidemiology* / Q000208:ethnology; D004196:Disease Outbreaks; D005260:Female; D006801:Humans; D008297:Male; D008800:Mexico / Q000208:ethnology; D012307:Risk Factors