-
[show abstract]
[hide abstract]
ABSTRACT: The meningococcal serogroup C conjugate (MCC) vaccine was introduced into the United Kingdom with licensure based on immunogenicity data not efficacy data.
All subjects with laboratory-confirmed meningococcal serogroup C (MenC) disease from January 2000 to December 2003 in England and Wales were followed up. A vaccine failure was defined as a laboratory-confirmed case of MenC disease occurring > or =10 days after the subject's last scheduled dose of MCC vaccine. Total immunoglobulins, serum bactericidal antibody (SBA) titers, MCC anticapsular antibody levels, and avidity indices (AIs) were measured in acute and convalescent serum samples from subjects with vaccine failure and unvaccinated subjects with MenC disease.
Of 465 subjects with confirmed MenC disease identified among those eligible for vaccination, information on vaccination history was obtained for 462 (99.4%); of these, 53 were subjects with vaccine failure. SBA titers in convalescent serum samples and AIs in acute serum samples were significantly higher in subjects with vaccine failure than in unvaccinated subjects, (6.1-fold higher for SBA titers [P=.03] and 3.2-fold higher for AIs [P=.001]).
The antibody response in the subjects with vaccine failure was consistent with an anamnestic response, suggesting that MenC disease occurred despite the MCC vaccine priming for immune memory. Persistence of antibodies may be a more appropriate correlate of long-term protection for MCC vaccines than the ability to generate a booster response on exposure.
The Journal of Infectious Diseases 12/2006; 194(12):1745-52. · 6.41 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Changes in the immunoglobulin G1 (IgG1)/IgG2 ratio following vaccination can indicate the activation of cellular control mechanisms typical of a T-cell-dependent response. We examined IgG subclass ratios in 17 healthy adults (26 to 55 years of age) before and 4 to 6 weeks following immunization with a quadrivalent meningococcal-polysaccharide diphtheria toxoid conjugate vaccine against serogroups A, C, Y, and W135. Serologic responses were determined by serum bactericidal antibody assay and serogroup-specific IgG, IgG1, and IgG2 enzyme-linked immunosorbent assay. Prevaccination serogroup A-specific IgG1/IgG2 ratios were <1 for all subjects and differed by subject for C, Y, and W-135. Postvaccination, significant increases in IgG, IgG1, and IgG2, were observed for all serogroups. Serogroup-specific IgG1/IgG2 ratios increased for group A (14/17 subjects, 88%), decreased in more than half of subjects for groups C (9/17, 53%) and W135 (12/17, 71%) and decreased for serogroup Y (16/17, 94%). IgG1/IgG2 ratios differed between individual vaccinees and were similar to the responses of adults who received pneumococcal conjugate vaccines or a monovalent C conjugate vaccine. Further studies on IgG subclasses following meningococcal polysaccharide and conjugate vaccination are needed.
Clinical and Vaccine Immunology 04/2006; 13(4):507-10. · 2.55 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Changes in the immunoglobulin G1 (IgG1)/IgG2 ratio following vaccination can indicate the activation of cellular control mechanisms typical of a T-cell-dependent response. We examined IgG subclass ratios in 17 healthy adults (26 to 55 years of age) before and 4 to 6 weeks following immunization with a quadrivalent meningococcal-polysaccharide diphtheria toxoid conjugate vaccine against serogroups A, C, Y, and W135. Serologic responses were determined by serum bactericidal antibody assay and serogroup-specific IgG, IgG1, and IgG2 enzyme-linked immunosorbent assay. Prevaccination serogroup A-specific IgG1/IgG2 ratios were <1 for all subjects and differed by subject for C, Y, and W-135. Postvaccination, significant increases in IgG, IgG1, and IgG2, were observed for all serogroups. Serogroup-specific IgG1/IgG2 ratios increased for group A (14/17 subjects, 88%), decreased in more than half of subjects for groups C (9/17, 53%) and W135 (12/17, 71%) and decreased for serogroup Y (16/17, 94%). IgG1/IgG2 ratios differed between individual vaccinees and were similar to the responses of adults who received pneumococcal conjugate vaccines or a monovalent C conjugate vaccine. Further studies on IgG subclasses following meningococcal polysaccharide and conjugate vaccination are needed. A quadrivalent serogroup A, C, W135, and Y polysaccharide conjugate vaccine (Menactra) has recently been licensed in those of ages 11 to 55 years in the United States on the basis of safety and immunogenicity data collected from American children and adults (2). Conjugation of four meningococcal polysaccharides to a protein carrier produces T-cell-dependent responses, unlike the T-cell-independent responses induced by plain polysaccharide vaccines. Avidity indices have been used to measure immune responses to vaccines in infants and young children to demonstrate antibody maturation (3); however, such indices are not as useful in adults, most of whom have had previous exposure to pathogens, with the result that vaccina-tion provides a booster, rather than a primary, immune re-sponse in this age group (6). It has been suggested that a vaccine's ability to increase the immunoglobulin G1 (IgG1)/ IgG2 ratio may indicate the activation of cellular control mech-anisms typical for T-cell-dependent responses, as has been observed for pneumococcal conjugate vaccines in children (12, 19, 20). However, available data for meningococcal vaccines are scant; a single study of IgG subclasses after monovalent meningococcal group C conjugate vaccine has been published (8). In general, IgG subclass data for adults have been equiv-ocal (8, 12, 19, 20), making the acquisition of further data of interest. We report the IgG1 and IgG2 subclass response to Menactra vaccine in 17 healthy adults evaluated in the United Kingdom.
Clinical and Vaccine Immunology 01/2006; 13:507-510507. · 2.55 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Two hundred health care workers in England and Wales were vaccinated with the Lister/Elstree strain of the vaccinia virus, and completed health diaries for 21 days or until the lesion had scabbed over. Pain and temperature were measured daily, and all other symptoms recorded freehand by the vaccinee. One hundred and forty two (71%) vaccinees reported pain, of which 25% considered it to be moderate or severe; 32 vaccinees (16%) recorded a temperature of >37.7 degrees C, two of which exceeded 39 degrees C. Other, mainly trivial, adverse events were common; itch was reported in 72%, erythema in 27%, axillary pain or lymphadenopathy in 38%, malaise or flu-like symptoms in 40% and headache in 23%. The incidences of minor adverse events were lower in re-vaccinees, compared with naïve vaccine recipients, significantly so in the case of erythema and general malaise (p=0.001 and 0.006, respectively), perhaps reflecting pre-existing immunity. Major adverse events occurred in two vaccinees (hospital admission, one with cellulitis and one with headache and possible encephalitis), and a further five were treated with antibiotics for local cellulitis. This is the first study to report results derived from active follow-up by diaries in recipients of the Lister/Elstree strain of vaccinia, and to document reductions in trivial adverse events in re-vaccinees.
Vaccine 08/2005; 23(32):4185-7. · 3.77 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A splenectomized patient with systemic lupus erythematosus, who had previously been treated with high doses of corticosteroids, presented with headaches and symptoms of a respiratory tract infection. A magnetic resonance imaging scan of the brain revealed a ring-enhancing lesion, and Nocardia asteroides was isolated from a stereotactic biopsy specimen. After adverse reactions to a number of antibiotics, infection control was finally achieved by the new oxazolidinone drug, linezolid. Nocardiosis should be considered as a differential diagnosis in all immunocompromised patients who develop an obscure infection; delay in diagnosis and subsequent initiation of appropriate treatment often results in a fatal outcome. Linezolid is a new option for the treatment of nocardiosis and is effective when given orally.
JCR Journal of Clinical Rheumatology 03/2003; 9(1):47-50. · 1.36 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A real-time PCR assay identified linezolid-resistant Enterococcus faecalis and Enterococcus faecium isolates with a G2576U rRNA mutation. PCR-restriction fragment length polymorphism analysis of ribosomal DNA amplicons with NheI also detected this mutation. Both assays detected isolates heterozygous at this position. Recognition of isolates with what is presently the most frequent oxazolidinone resistance mutation may aid surveillance and individual case management.
Journal of Clinical Microbiology 12/2002; 40(11):4298-300. · 4.15 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Linezolid, the first oxazolidinone antibacterial agent to be developed for clinical use, was licensed in the UK in early 2001. We report the first three examples of resistant enterococci (two isolates of Enterococcus faecium and one Enterococcus faecalis) isolated in the UK, which were obtained from patients who had received linezolid. The linezolid MICs for the resistant isolates were 64 mg/L. Pulsed-field gel electrophoresis (PFGE) analysis of the linezolid-susceptible and -resistant isolates from two of the patients, combined with sequence analysis of rRNA, indicated that resistance developed in previously susceptible strains, most probably via a point mutation in the 23S rRNA.
Journal of Antimicrobial Chemotherapy 12/2002; 50(5):743-6. · 5.07 Impact Factor
