Adult tetanus, diphtheria and pertussis immunization: knowledge, beliefs, behavior and anticipated uptake.

BACKGROUND: Lifetime protection against pertussis has been adopted as a goal of immunization programs in Canada. To anticipate adult coverage with a combined product containing tetanus (T) and diphtheria (d) toxoids and acellular pertussis (aP) vaccine as a booster dose, we conducted a survey of households in British Columbia, Canada.
METHODS: In a random telephone survey involving 800 adults, 25 years of age and older, we assessed current behaviors related to adult Td immunization and beliefs regarding pertussis vaccine under various scenarios relevant to adult decision-making.
RESULTS: Forty-five percent of participants reported having received tetanus vaccine within the previous 10 years; this rate was lowest amongst elderly persons 65 years of age or more (28%). On multi-variate analysis, being up-to-date with tetanus immunization was independently associated with belief that an adult should be immunized against tetanus and perception that tetanus is life-threatening and inversely associated with being elderly. At baseline, 59% of respondents indicated willingness to receive pertussis immunization if provided free; this increased to 76% following sequential information about communicability and severity of pertussis illness and safety, efficacy and convenience of vaccine and up to 87% if accompanied by physician or nurse recommendation. Sixty-three percent of adults indicated they would receive the vaccine if required to pay $40.00 (Cdn) for it.
CONCLUSIONS: Personal risk perception, public funding and physician recommendation are important to adults when considering tetanus and pertussis immunization. These factors may be relevant as immunization programs are expanded to include more adults generally.