Pre-event Smallpox Vaccination for Healthcare Workers Revisited – the Need for a Carefully Screened Multidisciplinary Cadre
Abstract As healthcare institutions are a focus of smallpox transmission early in an epidemic, several mathematical models support pre-event smallpox vaccination of healthcare workers (HCWs). The deciding factor for HCW voluntary vaccination is the risk of disease exposure versus the risk of vaccine adverse events. In a United States military population, with careful screening to exclude atopic dermatitis/eczema and immunosuppression, over 1 million vaccinia vaccinations were delivered with 1 fatality attributed to vaccination. Among 37,901 U.S. civilian volunteer healthcare workers vaccinated, 100 serious adverse events were reported including 10 ischemic cardiac episodes and six myocardial infarctions – 2 were fatal. This older population had a higher rate of adverse events due to age related coronary artery disease. T-cell mediated inflammatory processes, induced by live vaccinia vaccination, may have a role in the observed acute coronary artery events. With exclusion of individuals at risk for coronary artery disease, atopic dermatitis/eczema, and immunosuppression, HCWs can be smallpox vaccinated with minimal risk. A smallpox pre-vaccinated multidisciplinary cadre (physician, nurse, infection control practitioner, technician) will supply leadership to deal with fear and uncertainty while limiting spread and initial mortality of smallpox. Stochastic – from the Greek meaning “skillful in aiming” – is currently interpreted as arising from chance and involving probability. This issue’s article “Containing a large bioterrorist smallpox attack: a computer simulation approach” by Longini et al. is a discrete time, stochastic computer simulation model that offers additional planning guidance for a smallpox (variola virus) outbreak (1). Although interpretation of the model’s information may differ, Longini’s article concludes “Given that surveillance and containment measures are in place, preemptive vaccination of hospital workers would further reduce the number of smallpox cases and deaths, but would require large numbers of prevaccinations” for the greatest effectiveness. In their simulation, the hospital has 686 workers (a relatively small facility compared to many tertiary care institutions) and 133 make close contact with smallpox cases prior to the initiation of isolation measures. Of 828 cases, 50% originated in the hospital and 13% of the contacts were untraceable. Preemptive smallpox (vaccinia virus) vaccination of 10% of the hospital workers, in addition to surveillance and containment, had a small effect on the average number of cases; however, preemptive vaccination of 50% of the hospital workers had a relatively large effect on case reduction. The larger number of preemptive vaccinations required less contact tracing and “ring” containment vaccinations. A delay of one day in fully implementing surveillance and containment resulted in a large epidemic.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 901169
- Report Number(s):
- PNNL-SA-51243; TRN: US200713%%76
- Journal Information:
- International Journal of Infectious Diseases, 11(2):93-97, Vol. 11, Issue 2
- Country of Publication:
- United States
- Language:
- English
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