Skip to main content Accessibility help

Outbreak of Varicella-Zoster Virus Infection Among Thai Healthcare Workers

  • Anucha Apisarnthanarak (a1), Rungrueng Kitphati (a2), Pranee Tawatsupha (a2), Kanokporn Thongphubeth (a3), Piyaporn Apisarnthanarak (a4) and Linda M. Mundy (a5)...



To evaluate the correlation between self-report of a prior history of chickenpox and results of varicella-zoster virus (VZV) immunoglobulin (Ig) G serologic test results in an outbreak of VZV infection among Thai healthcare workers (HCWs) and to conduct a cost-benefit analysis of establishing routine VZV immunization as part of an occupational health program on the basis of the outbreak data.


All exposed patients received prophylaxis and the HCWs in our 3 intensive care units (ICUs) were prospectively evaluated. HCWs were assessed for disease history and serologic evidence of VZV IgG. A cost-benefit analysis was performed.


After 140 HCWs and 18 ICU patients were exposed to VZV, 10 HCWs (7%) with active VZV infection were relieved from work until skin lesions were crusted. Acyclovir (ACV) was prescribed to all 10 HCWs with active disease, and all 18 exposed patients received prophylaxis with ACV. Of 140 HCWs, 100 consented to longitudinal follow-up. Twenty-three (100%) of the HCWs who reported a history of chickenpox also had serologic test results that were postive for VZV IgG, compared with 30 (39%) of 77 HCWs who reported no prior history of chickenpox, yet had test results that were positive for VZV IgG. Reported history of chickenpox had a sensitivity of 43%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 61% with respect to VZV infection immunity. The total cost estimate for this outbreak investigation was $23,087.


An HCWs reported history of chickenpox was a reliable predictor of immunity; a report of no prior history of chickenpox was unreliable. Our cost-benefit analysis suggests that the costs of an occupational health program that included VZV surveillance and immunization for the next 323 HCWs would be approximately equal to the excess costs of $17,227 for the ACV therapy, HCW furloughs, and staff overtime associated with this outbreak.


Corresponding author

Division of Infectious Diseases, Faculty of Medicine, Thammasart University Hospital, Pratumthani, Thailand, 12120 (


Hide All
1.Almuneef, M, Dillon, J, Abbas, MF, Memish, Z. Varicella zoster virus immunity in multinational health care workers of a Saudi Arabian hospital. Am J Infect Control 2003;31:375381.
2.Shehab, ZM, Brunell, PA. Susceptibility of hospital personnel to varicella-zoster virus. J Infect Dis 1984;150:786.
3.Haiduven-Griffiths, D, Fecko, H. Varicella in hospital personnel: a challenge for the infection control practitioner. Am J Infect Control 1987;15:207211.
4.McKinney, WP, Horowitz, MM, Battiola, RJ. Susceptibility of hospital-based health care personnel to varicella-zoster virus infections. Am J Infect Control 1989;17:2630.
5.Lee, BW. Review of varicella zoster seroepidemiology in India and South-east Asia. Trop Med Int Health 1998;3:886890.
6.Longfield, JN, Winn, RE, Gibson, RL, et al.Varicella outbreaks in army recruits from Puerto Rico. Arch Intern Med 1990;150:970974.
7.Kjersem, H, Jepsen, S. Varicella among immigrants from the tropics, a health problem. Scand J Soc Med 1990;18:171174.
8.Kositanont, U, Wasi, C, Oonsombat, P, Suvatte, V, Thongcharoen, P. Susceptibility to varicella zoster virus in Thai children and young adults. Southeast Asian J Trop Med Public Health 1985;16:414420.
9.Ooi, PL, Goh, KT, Doraisingham, S, Ling, AE. Prevalence of varicella zoster virus infection in Singapore. Southeast Asian J Trop Med Public Health 1992;23:2225.
10.Danovaro-Holliday, MC, Gordon, ER, Jumann, AO, et al.High rate of varicella complications among Mexican-born adults in Alabama. Clin Infect Dis 2004;39:16331639.
11.Almuneef, M, Memish, ZA, Abbas, MF, Balkhy, HH. Screening healthcare workers for varicella-zoster virus: can we trust the history? Infect Control Hosp Epidemiol 2004;25:595598.
12.Prevention of varicella: update recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep 1999;48(RR-6):15.
13.Wharton, M, Strikas, RA, Harpaz, R, et al.Recommendations for using smallpox vaccine in a pre-event vaccination program: supplemental recommendations of the Advisory Committee on Immunization Practices (ACIP) and the Healthcare Infection Control Practices Advisory Committee (HICPAC). MMWR Recomm Rep 2003;52(RR-7):116.
14.Jackson, MM, Lynch, P. Guideline for isolation precautions in hospitals, 1996. Am J Infect Control 1996;24:203206.
15.Wallace, MR, Chamberlin, CJ, Zerboni, L, et al.Reliability of a history of previous varicella infection in adults. JAMA 1997;278:15201522.
16.Richard, VS, John, TJ, Kenneth, J, Ramaprabha, P, Kuruvilla, PG, Chandy, GM. Should health care workers in the tropics be immunized against varicella? J Hosp Infect 2001;47:243245.
17.Alagappan, K, Fu, L, Strater, S, Atreidis, V, Auerbach, C. Seroprevalence of varicella antibodies among new house officers. Ann Emerg Med 1999;33:516519.
18.Schaffer, SJ, Bruno, S. Varicella immunization practices and the factors that influence them. Arch Pediatr Adolesc Med 1999;153:357362.
19.Jerant, AF, DeGaetano, JS, Epperly, TD, Hannapel, AC, Miller, DR, Lloyd, AJ. Varicella susceptibility and vaccination strategies in young adults. J Am Board Fam Pract 1998;11:296306.
20.Brotherton, JML, Bartlett, MJ, Muscatello, DJ, Campbell-Lloyd, S, Stewart, K, McAnulty, JM. Do we practice what we preach? Health care worker screening and vaccination. Am J Infect Control 2003;31:144150.
21.Puzniak, LA, Gillespie, KN, Leet, T, Kollef, M, Mundy, LM. A cost-benefit analysis of gown use in controlling vancomycin-resistant Enterococcus transmission: is it worth the price? Infect Control Hosp Epidemiol 2004;25:418424.
22.Lolekha, S, Tanthiphabha, W, Sornchai, P, et al.Effect of climatic factors and population density o n varicella-zoster virus epidemiology within a tropical country. Am J Trop Med Hyg 2001;64:131136.
23.Behrman, A, Schmid, DS, Crivaro, A, Watson, B. A cluster of primary varicella cases among healthcare workers with false positive varicella zoster virus titers. Infect Control Hosp Epidemiol 2003;24:202206.
24.Zimmerman, L, Fajardo, M, Seward, J, Ludwig, S, Johnson, J, Wharton, M. Varicella susceptibility and validity of history among US Coast Guard recruits: an outbreak-based study. Mil Med 2003;168:404407.
25.Lieu, TA, Black, SB, Rieser, N, Ray, P, Lewis, EM, Shinefield, HR. The cost of childhood chickenpox: parents' perspective. Pediatr Infect Dis J 1994;13:173177.
26.Paul, JE, Mauskopf, JA, Bell, L. Cost-consequence models for varicella-zoster virus infections. Pharmacotherapy 1995;15:49S58S.
27.Somekh, E, Dalal, I, Shohat, T, Ginsberg, GM, Romano, O. The burden of uncomplicated cases of chickenpox in Israel. J infect 2002;45:233236.
28.American Academy of Pediatrics. Committee on Infectious Diseases. Varicella vaccine update. Pediatrics 2000;105:136141.

Related content

Powered by UNSILO

Outbreak of Varicella-Zoster Virus Infection Among Thai Healthcare Workers

  • Anucha Apisarnthanarak (a1), Rungrueng Kitphati (a2), Pranee Tawatsupha (a2), Kanokporn Thongphubeth (a3), Piyaporn Apisarnthanarak (a4) and Linda M. Mundy (a5)...


Altmetric attention score

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed.