Vaccine
-
Randomized Controlled Trial Comparative Study
Comparison of a single, high-dose vaccination regimen to the standard regimen for the investigational Japanese encephalitis vaccine, IC51: a randomized, observer-blind, controlled Phase 3 study.
The standard administration of the investigational Japanese encephalitis vaccine IC51 is 2 doses of 6 microg with a 28-day interval. This study investigated the immunogenicity of a single-immunization, high-dose regimen (1 x 12 microg) compared to the 2-injection, standard regimen to determine the immune response that one, high-dose injection can confer. The single, high-dose regimen resulted in about 60% seroconversion rate (SCR) at 10 days after administration, but it did not reach the almost 100% SCR achieved by the 2-dose standard administration at Day 35. The standard regimen conferred essentially 100% seroconversion already 7 days after the second immunization.
-
Multicenter Study
Clinical effectiveness of 23-valent pneumococcal polysaccharide vaccine against pneumonia in middle-aged and older adults: a matched case-control study.
The 23-valent polysaccharide pneumococcal vaccine is currently recommended in elderly and high-risk adults. Its efficacy against invasive pneumococcal disease has been demonstrated, but its effectiveness in preventing pneumonia remains uncertain. This study assessed the clinical effectiveness of vaccination against pneumonia among middle-aged and older adults. ⋯ Vaccination was effective against bacteremic cases (OR: 0.34; 95% CI: 0.27-0.66) as well as nonbacteremic cases (OR: 0.58; 95% CI: 0.39-0.86). Vaccine effectiveness was highest against bacteremic infections caused by vaccine types (OR: 0.24; 95% CI: 0.09-0.66). These findings confirm the effectiveness of the vaccine against invasive disease, but they also support the benefit of vaccination in preventing nonbacteremic pneumococcal pneumonia.
-
Rotavirus is the most common cause of severe diarrhea in children. Two rotavirus vaccines (RotaTeq and Rotarix) have been licensed in Taiwan. We have investigated whether routine infant immunization with either vaccine could be cost-effective in Taiwan. ⋯ Despite a higher burden of serious rotavirus disease than estimated previously, routine rotavirus vaccination would unlikely be cost-saving in Taiwan at present unless the price fell to US$41 (Rotarix) or US$29 (RotaTeq) per dose from societal perspective, respectively. Nonetheless, rotavirus immunization could reduce the substantial burden of short-term morbidity due to rotavirus.
-
This article considers the investment case for using the Vi polysaccharide vaccine in developing countries from two perspectives: reducing typhoid cases and limiting new health care spending. A case study is presented using data from South and Southeast Asia. The purpose of the paper, however, is to draw broad implications that may apply to developing countries in general. ⋯ However, equal prices for children and adults produce very similar results, and they might be more readily accepted by the community. Alternatively, if vaccines are free, the number of cases is not significantly reduced compared to either pricing policy, but a large external financial contribution from government or donors would be required. A Monte Carlo simulation explores the effects of uncertain parameters on vaccination program outcomes.
-
Influenza-pseudotyped Gag virus-like particles (VLPs) were produced via the expression of influenza hemagglutinin (HA), neuraminidase (NA) and the murine leukemia virus Gag product in the baculovirus-insect cell expression system. Hemagglutination specific activities of sucrose gradient-purified VLPs were similar to those of egg-grown influenza viruses but particle morphologies were gamma retrovirus-like in the form of consistent 100nm spheres. Immunization of mice and ferrets demonstrated robust immunogenicity and protection from challenge with no measurable morbidity. ⋯ H1N1 VLP immunization of ferrets resulted in partial protection against H5N1 challenge with markedly accelerated virus clearance from the upper respiratory tract relative to controls. The immunogenicity of influenza-pseudotyped VLPs was not dependent on the adjuvant properties of replication competent contaminating baculovirus. These data demonstrate robust vaccine protection of Gag-based, influenza-pseudotyped VLPs carrying a variety of influenza antigens and suggest applicability toward a number of additional respiratory viruses.