Abstract:
The adult population in Sri Lanka is having high level of susceptibility for Varicella Zoster Virus (VZV)
infection. Among medical undergraduates, 47% are VZV seronegative. The purpose of the present study was to
determine the incidence of VZV infection in medical undergraduates in Sri Lanka, and to describe the effects of VZV
infection on their academic activities.
Methods: A retrospective cohort of medical undergraduates' susceptible for VZV infection was selected from the
University of Peradeniya, Sri Lanka. Data on the incidence of VZV infection (Chickenpox) during their undergraduate
period was collected using a self-administered structured questionnaire. A second questionnaire was administered to
collect data on the details of VZV infection and the impact of it on their academic activities. VZV incidence rate was
calculated as the number of infections per 1,000 person years of exposure. Descriptive statistics were used to describe
the impact of VZV infection on academic activities.
Results: Out of the 172 susceptible cohort, 153 medical undergraduates were followed up. 47 students reported VZV
infection during the follow up period and 43 of them participated in the study. The cumulative incidence of VZV
infection during the period of five and half years of medical training was 30.7%. Incidence density of VZV infection
among medical undergraduates in this cohort was 65.1 per 1,000 person years of follow-up. A total of 377 working days
were lost by 43 students due to the VZV infection, averaging 8.8 days per undergraduate. Total academic losses for the
study cohort were; 205 lectures, 17 practicals, 13 dissection sessions, 11 tutorials, 124 days of clinical training and 107
days of professorial clinical appointments. According to their perception they lost 1,927 study hours due to the illness
(Median 50 hours per undergraduate).
Conclusions: The incidence of VZV infection among Sri Lankan medical undergraduates is very high and the impact of
this infection on academic activities causes severe disruption of their undergraduate life. VZV immunization for
susceptible new entrant medical undergraduates is recommended.
