Reactogenicity Profile of Tetanus‐Diphtheria (Adult‐Type) Vaccine: Results of a Naturalistic Study Performed at an Adult Vaccination Center

Abstract

A prospective observational naturalistic study was conducted at a vaccination center to assess the reactogenicity of tetanus-diphtheria (adult-type) (Td) vaccine. In 1 year, 3072 adult subjects were invited to participate, of whom 1977 (62% women, mean age [+/- SD]: 39 [+/- 14.5] years [range: 18-85 years]) actively did so. A follow-up diary card was provided to all subjects to record all local and general symptoms experienced during the following 4 days after vaccination. Of the study population (n = 1977), 280 received a second Td dose, and 30 received a third dose: the total number of diary cards collected was 2287. Td was always administered (i.m. route) in the left arm. The study population was grouped by age: 52%, 41%, and 7% were ages 18 to 35, 36 to 65, and > 65 years, respectively, most of them being travelers to developing countries. Close to two-thirds of subjects received up to nine different vaccines (mainly hepatitis B, hepatitis A, and typhoid) in addition to Td. Adverse reactions were classified as mild, moderate, and severe. Overall, 50% of subjects reported some type of adverse reaction. Pain, discomfort with arm movement, swelling, malaise, and fever (axillary temperature > or = 38 degrees C) were recorded in 43%, 14%, 3.8%, 5.1%, and 1.7% of all diary cards, respectively. Local and general reactions were considered as mild by almost two-thirds of vaccinees and lasted < or = 48 hours in about three-fourths of them. The incidence of moderate plus severe local reactions was significantly (p < 0.01) more commonly reported in the 18- to 35-year-old group than in the 36- to 65-year-old group. No statistically significant differences were observed when comparing the incidence of general adverse reactions of those receiving Td alone with those receiving additional vaccines or when comparing the duration and intensity by age groups. Only 5.2% of subjects required analgesic/antipyretic treatment. In conclusion, this study shows that Td vaccine is reasonably well tolerated when given alone or with other vaccines. Similar studies should be conducted with other vaccines routinely recommended to adults to assess how they are administered in usual clinical practice and the reactogenicity profile perceived by the vaccinees.