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Our results show that the vaccine is safe and effective and should be recommended to TXL-R.

Vaccination against influenza is considered to be one of the key interventions in case of a pandemic. Unfortunately, shortages in vaccine supplies will occur because of the substantial increase in vaccine demands worldwide and the limited available supply resources. The recommended use of monovalent--instead of current trivalent--vaccines containing 15 micro g hemagglutinin (HA) per dose can theoretically triple vaccine volumes but is unlikely to meet the demand. Furthermore, previous experiences demonstrated that one dose of 15 micro g HA will not be sufficient to elicit protective antibody levels in unprimed individuals. Modified formulation approaches were investigated, that would be suitable to provide significantly higher volumes of potent vaccine within a given period of time. Low doses of HA combined with aluminum (Al) adjuvants and the use of whole virus instead of split or subunit antigens can lead to substantial increases in process yield. In addition, production of whole virus vaccines will reduce manufacturing complexity. In a dose-finding study in healthy adults and elderly, immune responses after administration of Al-adjuvanted low-dose formulations were compared to a standard split virus vaccine (Fluarix, GlaxoSmithKline Biologicals, Rixensart, Belgium). All vaccines were safe and well tolerated. Antigen concentrations as low as 1.9 micro g HA/strain per dose of adjuvant-containing experimental vaccines induced protective antibody levels in primed populations. Reactogenicity profiles of Al-adjuvanted low-dose vaccines were investigated in a feasibility trial. Neither the use of Al-adjuvant nor of whole virus had a significant effect on general reactions. Studies in unprimed populations with H2N2 and H9N2 candidate vaccines showed different results, with a potential need for a two-dose schedule. Indeed, hemagglutination inhibition titers did not reach protective levels after a single vaccine dose but could be met following administration of a second dose. The same is true for Al-adjuvanted whole virus formulations with an up to eightfold-reduced antigen content. It may be concluded that the use of Al-adjuvanted whole virus vaccines with low HA content can raise protective antibody levels after two vaccine doses, which may, in turn, result in significant increases of vaccine supplies in the case of a pandemic.

Several life-threatening infections, a major risk to adult solid organ transplant (SOT) recipients on immunosuppressive therapy, can be prevented by immunization. We analyzed sociodemographic parameters and the immunization status of adult liver transplant recipients (LTX-R, n=267) and renal transplant recipients (RTX-R, n=197) SOT recipients at the Transplantation Center, Berlin, Germany. Date, number, and provider of recommended vaccines were recorded and seroprotection rates determined. The social status in both groups was similar. Most patients (89%) were not adequately informed about immunizations; and if informed, main sources were physicians (47%) and the media (40%). Vaccinations were predominantly provided by family doctors (LTX-R, 66%; RTX-R, 31%) or hemodialysis centers (RTX-R, 37%). Before transplantation, RTX-R had significantly more often received booster vaccinations against tetanus and diphtheria (P<0.005), and a primary hepatitis B immunization (55%); whereas in LTX-R, post-transplant vaccinations against hepatitis A (16%) and pneumococcal disease (13%) were more frequent. Seroprotection rates against tetanus were fairly high in LTX-R (85.3%) and RTX-R (86.8%), and considerably lower for diphtheria, hepatitis A, and influenza. Immunization rates are too low in SOT recipients. Improvement will depend on a more active role of health care providers.

The aim of this serological study was to demonstrate the extent to which antibodies react against subsequent drift variants, after vaccination with split vaccine (Fluarix^TM). Antibody titers have been determined by hemagglutination inhibition test (HI) against different influenza A and B drift variants in sera from three past multicenter trials. Individuals of two different age groups, i.e. 18–60 years and above 60 years, were enrolled. Vaccine components influenza A/H1N1 and influenza B of Fluarix^TM show a high degree of cross immunogenicity against subsequent homologous drift variants. The genetically more variable component influenza A/H3N2 shows somewhat lower protection rates. High levels of cross immunogenicity were found between the variants of influenza A/Panama/2007/99 (H3N2) and influenza A/Wyoming/3/2003 (H3N2). The results demonstrate that in situations where drift variants emerge too late to be included in the influenza vaccine formulation, the cross-protection conferred must be evaluated on a case-by-case basis.

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