National paediatric immunization program of high risk groups: no effect on the incidence of invasive pneumococcal diseases.

This study monitors the epidemiology of invasive pneumococcal diseases (IPD) in hospitalized children up to 60 months of age before (February 2001-October 2004) and after (November 2004-January 2007) the introduction of a national risk group immunization program with "Prevenar" in Austria. The IPD incidence rates, per 100,000, for IPD were 7.6 before and 6.4 after the risk group immunization program, while there was a significant reduction (p<0.05) for meningitis, 3.1 before and 1.6 after. Overall, the most commonly observed serotypes were 14 (34.2%), 6B (11.7%), and 23F (6.7%). 71.7% of the identified strains were vaccine types; 12.5% were vaccine-related serotypes. No clinically relevant changes in the incidence rate of IPDs or shift/replacement of serotypes was documented. Antimicrobial resistance predominated against erythromycin (32.5%) and clarithromycin (26.7%). Our data show that this risk group vaccination program had no impact on the incidence of IPD in young children.

Safety and immunogenicity of a Vero-cell-derived, inactivated Japanese encephalitis vaccine: a non-inferiority, phase III, randomised controlled trial.

BACKGROUND: Japanese encephalitis virus (JEV) is the leading cause of viral encephalitis in southeast Asia. Although no treatment is currently available, vaccination effectively prevents the disease. In a non-inferiority study, we aimed to compare the safety and immunogenicity of a novel, second-generation, inactivated candidate vaccine for JEV with a licensed, mouse-brain-derived vaccine. METHODS: We included 867 adults in a multicentre, multinational, observer-blinded, randomised controlled phase III trial. Study sites were located in the USA, Germany, and Austria. Volunteers received either the JEV test vaccine intramuscularly on a two-dose schedule (on days 0 and 28; n=430) or the licensed vaccine subcutaneously according to its recommended three-dose schedule (on days 0, 7, and 28; n=437). The primary endpoint was immunogenicity, with respect to neutralising JEV-specific antibodies assessed by a plaque-reduction neutralisation test, which was assessable in 725 patients in the per-protocol population. This trial is registered as a clinical trial, EudraCT number 2004-002474-36. FINDINGS: The safety profile of the test vaccine was good, and its local tolerability profile was more favourable than that of the licensed vaccine. Frequency of adverse events was similar between treatment groups, and vaccine-related adverse events were generally mild. The seroconversion rate of the test vaccine was 98% compared with 95% for the licensed vaccine on day 56 (95% CI for the difference -1.33 to 3.43). Geometric mean titre for recipients of the test vaccine was 244 (range 5-19 783), compared with 102 (5-1864) for the licensed vaccine (ratio 2.3 [95% CI 1.967-2.75]). INTERPRETATION: The test JEV vaccine has a promising immunogenicity and safety profile.

Persistence of protective immunity following vaccination against tick-borne encephalitis--longer than expected?

A descriptive evaluation of protective immunity was performed on subjects with a complete primary tick-borne encephalitis (TBE) immunization (and additional regular boosters) more than 3 years after primary or booster TBE immunization, as measured by neutralization test and two different ELISA systems. The study population (n = 430) was stratified for age (i.e., 18-49 or 50 years of age) and for the number of years since last TBE vaccination. GMTs (NT) of all subgroups (at the time of the present evaluation) were above detection limit: 144 and 44 for the 18-49- and 50-year-old subjects, respectively. One percent of subjects aged 18-49 years, and 6% of subjects aged 50 years were ELISA-negative. A detailed sub analysis revealed that subjects with either low NT and/or negative to borderline ELISA test results are usually older and constitute a higher number of subjects without any TBE booster vaccination compared to the respective test-positive subject group. From the fourth year (exceeding 3 years after last vaccination) titers show a decline rate of 6-7%. This study indicates that after multiple TBE (booster) immunizations protection surpasses the currently advised TBE booster interval of 3 years, thus supporting reconsideration of the recommendations for booster intervals.

Antibody-response to three recombinant hepatitis B vaccines: comparative evaluation of multicenter travel-clinic based experience.

The immunogenicity of three currently used hepatitis B vaccines was compared in an unselected study population in an every day travel clinical setting. Five hundred and eighteen vaccinees received Engerix-B (EB), 990 received Twinrix (TWX), and 366 were immunised with Gen-HB-Vax (GHB). Overall, 88.6% of the vaccinees, tested within the first 6 months after completion of the vaccination series, developed protective levels of anti-HBs (> or = 10 mIU/ml). However, GHB recipients showed significantly lower seroprotection rates (SPR) than EB and TWX recipients (79.3% vs. 87.7% vs. 92.3%, P < 0.000001). GMTs for anti-HBs, tested within 6 months after the third vaccination, showed the lowest results in the GHB group, followed by EB and TWX (142 vs. 523 vs. 1008 mIU/ml, P < 0.000001). TWX vaccinees, however, showing a higher antibody decline rate than EB recipients within the first years after completion of the full immunisation course (30% vs. 25%; P = 0.0538). This study confirms an overall good immune response to the 20 microg-dose vaccine, in the course of a regular clinical setting. The significant difference in SPRs and GMTs to the 10 microg-dose vaccine, however, may influence future immunisation practices for the elderly.