Background: The goal of the National Smallpox Vaccination Program was to vaccinate a cadre of healthcare workers and first responders who could care for smallpox patients in the event of an attack.
Methods: Using a convenience sample of 36 health departments and 34 hospitals in California, we conducted a telephone interview between July 2003 and April 2004 of healthcare workers and first responders to determine predictors of smallpox vaccination.
Findings: The response rate was 54.1%. Of 477 respondents with no contraindications to vaccination, 106 were vaccinated and 371 were unvaccinated. Among the vaccinated, the leading reason for vaccination was wanting to be part of a smallpox response team (74%). Among the unvaccinated, leading reasons for not being vaccinated included thinking the risk of smallpox was not high enough (25%) and concern about side effects (19%). Factors independently associated with vaccination include previous smallpox vaccination (adjusted odds ratio [AOR]=4.1, 95% confidence interval [CI]=1.2-14.1), having little or no concern about vaccine adverse events (AOR=3.0, CI=1.3-7.0, compared with somewhat/very), reporting their employer had a policy to reimburse for travel or other out of pocket costs (AOR=2.5, CI=1.1-5.7, compared with no policy), very high to high chance of compensation if adverse events occurred (AOR=2.9, CI=1.2-6.3, compared with low chance), and answering in the negative to questions about concerns about potential costs. Blacks were less likely than whites to be vaccinated (AOR=0.04, CI=0.03-0.6).
Conclusions: Clearly communicating the risks and benefits of vaccination and addressing issues of cost, convenience, and compensation may be important for any program where vaccination is provided in the national interest and when the direct benefits of vaccination are unknown.