Reactogenicity profile of a combined hepatitis A and B vaccine in clinical practice: a naturalistic study in adult travellers

A prospective observational naturalistic study was conducted to assess the reactogenicity of the combined hepatitis A and hepatitis B (HAB) vaccine in a real-life setting. All healthy candidates for HAB vaccination attending an adult vaccination centre between October 1998 and February 2000 were invited to participate in the study. A follow-up diary card was provided to subjects to record local and general symptoms during a 4-day follow-up. Intensity was graded from 1 to 3. Redness was recorded as presence or absence. Fever was defined as axillar temperature ≥37.5 °C and grade 3 >39.0 °C. For all other symptoms, grade 3 was defined as an adverse reaction preventing normal everyday activities; 998 subjects (74% females), mean age (±S.D.) of 23 years (±4.5) (range: 11–54 years) agreed to participate. At first immunization 92% were <30 years old. Grade 3 pain and swelling was recorded in 1.2% and 0.3% of local symptom sheets completed, respectively; 438 subjects received the HAB vaccine alone (group 1) whereas 560 received at least one concomitant vaccine (group 2). In 45%, 27%, 18% and 10% of subjects the HAB vaccine was coadministered with 1, 2, 3 or 4 to 6 vaccines (mainly Td adult-type, typhoid, MMR and IPV vaccine). Grade 3 pain and swelling were recorded in 1.2% & 0.3% of symptom sheets (SS), respectively. In group 1, any fever and grade 3 fever was recorded in 3.5% and 0.1% of SS. Group 1 versus 2 had a lower risk for any fatigue (p = 0.0002; OR = 0.617) and any malaise (p = 0.0076; OR = 0.693) but not for grade 3 symptoms. In conclusion, our study showed that the HAB vaccine is well tolerated in adults either alone or coadministered with other vaccines in the routine clinical practice.