Publications by authors named "Thomas Papa"

Background: The live attenuated tetravalent dengue vaccine (CYD-TDV) is licensed using a 0-, 6- and 12-month schedule in dengue-endemic areas. An effective shorter schedule may provide more rapid, optimal protection of targeted populations during vaccine campaigns in dengue-endemic countries. We compared immune responses to two schedules of CYD-TDV in a non-endemic population.

View Article and Find Full Text PDF

Background: Neisseria meningitidis is a leading cause of meningitis and septicemia globally. Recent shifts in serogroup dominance in some settings highlight the desirability of polysaccharide-conjugate vaccines with broader meningococcal coverage than serogroup C vaccines in widespread use.

Methods: We assessed the safety and immunogenicity of a single dose of meningococcal quadrivalent (A, C, W-135, Y) tetanus conjugate vaccine (TetraMen-T), administered at 1 year of age.

View Article and Find Full Text PDF

Background: In a previous study, a meningococcal diphtheria toxoid conjugate vaccine (MCV-4) triggered robust bactericidal antibody responses against serogroups A, C, Y, and W-135 in 2- to 10-year-old children. A subset of participants, 2 to 3 years of age at the initial vaccination, was evaluated for persistence of antibody, immune memory, and antibody avidity.

Methods: Participants were healthy children vaccinated 23 to 36 months earlier with MCV-4 (primed) or newly recruited meningococcal vaccine-naive 4-year-olds.

View Article and Find Full Text PDF

Immune responses to meningococcal conjugate (Menactra; MCV-4) and plain polysaccharide (Menomune-A/C/Y/W-135; PSV-4) vaccines against serogroups A, C, Y, and W-135 were assessed in 220 of 1037 Chilean children aged 2 to 10 years participating in a comparative safety trial. Both vaccines were generally well tolerated. Geometric mean serum bactericidal antibody (SBA) titers 28 days postvaccination were comparable in both groups for all four serogroups.

View Article and Find Full Text PDF

A randomised, modified, double-blind trial was conducted in children 2 to < 5 years of age to evaluate immunogenicity and reactogenicity of a meningococcal (serogroups A, C, Y, W135) diphtheria toxoid conjugate vaccine (MCV-4) in healthy children previously vaccinated with a monovalent meningococcal C conjugate vaccine. Participants received one dose of either MCV-4 or Haemophilus influenzae type b vaccine (Hib vaccine, control group). Serum bactericidal antibodies (SBA) were determined in sera obtained before and approximately 28 days following vaccination.

View Article and Find Full Text PDF

Objective: A meningococcal (groups A, C, Y, and W-135) polysaccharide diphtheria toxoid conjugate vaccine (MCV-4; Menactra; Sanofi Pasteur Inc, Swiftwater, Pa) was developed to improve the profile of currently licensed products. The objective of this study was to compare the tolerability, immunogenicity, and immune memory of MCV-4 with those of a quadrivalent polysaccharide vaccine (PSV-4; Menomune A/C/Y/W-135; Sanofi Pasteur Inc).

Design, Setting, Participants: A randomized, double-blind trial was performed at 11 clinical centers in the United States.

View Article and Find Full Text PDF

Background: A quadrivalent meningococcal diphtheria conjugate vaccine (MCV-4) has been developed to provide T-cell dependent immune responses against 4 major disease-causing serogroups (A, C, Y, W-135).

Methods: In a comparative, randomized, modified double blind, controlled study in healthy 2- to 10-year-old U.S.

View Article and Find Full Text PDF

Background: Young children have the highest incidence of meningococcal infection. Approximately 50% of disease in United States children less than 2 years of age is caused by serogroups C and Y. In the developing world, serogroups A and W-135 cause outbreaks and epidemics of infection.

View Article and Find Full Text PDF

Meningococcal serogroup-specific immunoglobulin G (IgG), IgG1, and IgG2 concentrations were assigned to three reference sera, CDC 1992, 89-SF, and 96/562, for meningococcal serogroups A, C, Y, and W135 via the method of cross standardization. The sum of the serogroup-specific IgG1 and IgG2 concentrations determined for the four meningococcal serogroups showed good agreement with the serogroup-specific IgG either determined here or as previously represented. Following the assignment of meningococcal serogroup-specific IgG1 and IgG2 concentration to these reference sera, a meningococcal serogroup-specific IgG1 and IgG2 enzyme-linked immunosorbent assay protocol was developed.

View Article and Find Full Text PDF

Two-year-old children were vaccinated with 1 dose of meningococcal A/C conjugate (MACC) or meningococcal A/C polysaccharide (MACP) vaccine. Meningococcal serogroup A (MenA)-specific IgG geometric mean avidity indices (GMAIs) increased 1 month after vaccination with MACC (GMAI, 210; 95% confidence interval [CI], 140-300) and MACP (GMAI, 190; 95% CI, 120-310). One year after vaccination, the GMAI of the MACP-vaccinated cohort decreased to 130 (95%, CI 100-170), but a constant GMAI was maintained in the MACC-vaccinated cohort (210; 95% CI, 140-300), despite declining MenA-specific IgG antibody levels.

View Article and Find Full Text PDF

Healthy adults, 18-55 years old, were immunized once with a tetravalent (serogroups A, C, Y, and W-135) meningococcal vaccine conjugated to diphtheria toxoid at 1 of 3 doses and were monitored for safety, reactogenicity, and immunogenicity. No immediate reactions were observed. Only 1 of 89 subjects reported fever; only 1 reported any severe reactogenicity (local pain/soreness, chills, arthralgia, anorexia, and malaise).

View Article and Find Full Text PDF

Two injections of tetravalent (Groups A, C, Y and W-135) meningococcal polysaccharide vaccine conjugated to diphtheria were given to 30 toddlers at dosages of 1, 4 and 10 microg/ml polysaccharide of each serogroup. Reactogenicity was acceptable at all dosages. The 4-microg/ml dose appears to be immunologically optimal.

View Article and Find Full Text PDF