Induction of immunologic memory by conjugated vs plain meningococcal C polysaccharide vaccine in toddlers: a randomized controlled trial.

CONTEXT: Meningococcal polysaccharide vaccines are not used routinely in infants and toddlers, the groups at highest risk of invasive disease, because of poor immunologic responses to the Neisseria meningitidis serogroup C polysaccharide in these age groups. Meningococcal C conjugate vaccines offer the prospect of circumventing this problem. OBJECTIVE: To assess the immunogenicity and the induction of immunologic memory in toddlers by meningococcal C conjugate vaccine. DESIGN: A multicenter, randomized, observer-blinded controlled trial. SETTING: Urban and suburban family medicine or pediatric practices. PARTICIPANTS: Two hundred eleven healthy toddlers aged 15 to 23 months. INTERVENTION: Two injections at 2 months apart of meningococcal C conjugate (group 1, n = 69), plain meningococcal polysaccharide (group 2, n = 72), or hepatitis B virus vaccine (group 3, n = 70). All toddlers received a follow-up dose of plain meningococcal polysaccharide vaccine 12 months later. MAIN OUTCOME MEASURES: IgG meningococcal C anticapsular antibody concentrations determined by enzyme-linked immunosorbent assay and complement-mediated bactericidal antibody. RESULTS: In group 1, the magnitude of the IgG response to meningococcal C conjugate vaccine was more than 4-fold higher after dose 1 and more than 10-fold higher after dose 2 compared with meningococcal polysaccharide vaccine (group 2) (P<.001). Higher titers persisted in the meningococcal C conjugate group for at least 12 months (P<.001). Group 1, primed with meningococcal C conjugate, had 25-fold higher IgG responses to the meningococcal polysaccharide 1-year booster dose than the controls who had received hepatitis B virus vaccine initially and were given meningococcal polysaccharide vaccine 1 year later for the first time (P<.001). In contrast, group 2, primed with meningococcal polysaccharide, had a 2-fold lower response to the 1-year booster meningococcal polysaccharide dose than the hepatitis B virus control group (P = .006). Serum bactericidal responses paralleled the enzyme-linked immunosorbent assay responses. CONCLUSIONS: Immunization of toddlers with meningococcal C conjugate vaccine induces high titers of anticapsular and bactericidal antibody. Furthermore, this vaccine induces immunologic memory to meningococcal C polysaccharide. In contrast, meningococcal polysaccharide vaccine is less immunogenic than the conjugate vaccine and also induces a hyporesponsive state that persists for at least 12 months.

Microbiologic evaluation of needleless and needle-access devices.

OBJECTIVE: This study was carried out to determine whether needleless intravenous access devices are more likely to allow microorganisms to enter the fluid pathway than intravenous needle-access devices. METHODS: A laboratory study was conducted with two needleless and one intravenous needle-access devices and Enterococcus faecium as a bacterial challenge. Inocula of E. faecium were prepared on the basis of the numerical estimates of 1000 to 10,000 colony-forming units (CFU)/cm2 of bacterial flora on dry regions of skin (arms, legs, and hands). The septum of each access device was inoculated with 10 to 20 microliters of a 10(4) to 10(5) CFU/ml challenge suspension, which was allowed to dry on the surface of the septum. In the first part of the experiment, the needleless or needle-access cannula of each device was used to puncture the corresponding septum without previously disinfecting the top of the septum. In the second part, the contaminated septum was punctured after disinfecting the septum with a 70% isopropyl alcohol wipe. After each puncture, trypticase soy broth was flushed through the fluid pathway of the intravenous access device, collected, and cultured by the membrane filtration technique. The septum of each injection-site cap and the needleless or needle-access cannula were sampled with sterile premoistened swabs. Swabs were cultured on blood agar plates. RESULTS: The rate of fluid pathway contamination was 100% (40/40) for one of the needleless intravenous access devices and 80% (20/25) for the other when septa were contaminated with E. faecium and not disinfected before puncture. The rate for the intravenous needle-access device was 72% (18/25). When the septa of the three different devices tested were disinfected with 70% isopropyl alcohol, E. faecium was isolated on only one septum from all devices tested in part two (1/74, 1.3%). CONCLUSIONS: These laboratory studies demonstrate that there is no statistically significant difference in the rate of fluid pathway contamination between needleless and intravenous needle-access devices. However, if the septa of either needleless or needle systems are not disinfected before puncture, a high rate of fluid pathway contamination may occur.

Bloodstream infections associated with a needleless intravenous infusion system in patients receiving home infusion therapy.

OBJECTIVE: To determine risk factors for bloodstream infections (BSIs) in an outbreak among patients receiving home intravenous infusion therapy. DESIGN: Case-control and retrospective cohort studies. SETTING: Home health agency. PATIENTS: Patients receiving home intravenous infusion therapy from Rhode Island Home Therapeutics (RIHT) from January through December 1993. MAIN OUTCOME MEASURE: Development of primary BSI. METHODS: We compared patients with BSI (ie, case patients) with randomly selected noninfected RIHT patients receiving intravenous therapy, conducted a cohort study of all RIHT patients receiving intravenous therapy via a central venous catheter (CVC), and conducted a culture survey of injection cap luminal fluid. RESULTS: Case patients were more likely than controls to have had therapy via a CVC (11/11 vs 14/32; odds ratio [OR] undefined; P < .001) or total parenteral nutrition and intralipid therapy (TPN/IL) (9/11 vs 3/32; OR, 43.5; 95% confidence interval [CI], 4.9 to 510.0). Among RIHT patients with CVCs, risk factors for BSI were receipt of TPN/IL (9/35 vs 2/67; rate ratio [RR], 8.6; 95% CI, 2.0 to 37.7) or use of a needleless infusion system (10/41 vs 1/61; RR, 14.9; 95% CI, 2.0 to 111.8). Only the combination of both exposures was significantly associated with development of a BSI (P < .001). Luminal fluid from injection caps of needleless devices was significantly more likely to be culture positive than fluid from protected-needle devices (5/23 vs 0/18; RR undefined; P = .04). CONCLUSIONS: Our data suggest that a needleless device used for TPN/IL was associated with increased risk of BSI when injection caps were changed every 7 days.