Efectos de la vacunación antigripal sobre el porcentaje de linfocitos T CD4 positivos en pacientes VIH 1/2 positivos: estudio de una cohorte / Effects of influenza vaccination on the percentage of CD4+ T lymphocytes in HIV 1/2 positive patients: a cohort study

ObjetivoDeterminar la incidencia del cambio inmunitario del porcentaje de linfocitos T CD4+ en pacientes VIH 1/2 positivos en el primer trimestre posvacunación antigripal (P-CIR) y secundariamente comparar las características demográficas y clínicas relacionadas con dicho cambio.MétodosSe estudiaron 105 pacientes con VIH-sida de una cohorte retrospectiva hospitalaria entre 2001 y 2006. Se consideró P-CIR una disminución >3% del porcentaje de CD4+ prevacunal, y su asociación cruda y ajustada (sexo, edad, terapia antirretroviral, estabilidad clínica, carga viral prevacunal, CD4 total prevacunal) fue evaluada por regresión logística (odds ratio [OR] con intervalo de confianza del 95% [IC95%]).ResultadosLa incidencia del P-CIR fue del 33,3%, y fue persistente en un 31,4% durante los siete meses posvacunación independientemente de una viremia alta prevacunal. Asimismo, las variables demográficas y clínicas estudiadas no se relacionaron con la presencia de P-CIR, con una OR cruda de 0,90 (0,17–4,8) y una OR ajustada de 1,09 (0,17–6,8).ConclusionesLos datos encontrados reflejan que el cambio relevante del estado inmunitario no fue despreciable en la posvacunación, aunque mayoritariamente resultó transitorio(AU)

ObjectiveTo determine the incidence of immunologic change in the percentage of CD4+ T lymphocytes in HIV 1/2 positive patients in the first quarter after influenza vaccination (P-CIR) and to compare the demographic and clinical characteristics associated with this change.MethodsWe studied 105 patients with HIV/AIDS in a retrospective hospital cohort between 2001–2006. P-CIR was considered as a decrease of >3% in the prevaccination CD4+ percentage. Crude and adjusted OR (sex, age, antiretroviral therapy, clinical stability, prevaccination viremia and prevaccination total CD4) were evaluated by logistic regression (95%CI).ResultsThe incidence of P-CIR was 33.3%. P-CIR was persistent in 31.4% for 7 months after vaccination regardless of high prevaccination viremia. No association was found between demographic and clinical variables and P-CIR [crude OR: 0.90 (0.17–4.8); adjusted OR: 1.09 (0.17–6.8)].ConclusionsThe results showed that the immunological change after vaccination was not inconsiderable. However, this change was mainly transient(AU)

Kinetics of antibody response to Haemophilus influenzae type b vaccines. Pennridge Pediatric Associates.

Serum antibodies to the capsular polysaccharide of Haemophilus influenzae type b (Hib) are effective in preventing or ameliorating invasive disease caused by this human pathogen. Polysaccharide and conjugate (saccharide covalently linked to protein carrier) vaccines have been developed which stimulate the production of such antibodies. The polysaccharide-specific antibody concentrations in the sera of vaccine-naïve adults and toddlers on days 1, 3, 7, 14 and 28 following immunisation with one dose of the Hib polysaccharide vaccine (PRP, polyribosylribitol phosphate) or an oligosaccharide-CRM197 conjugate vaccine (HbOC, HibTITER) were determined. Antibody responses occurred within 7 days of immunisation with the maximum response usually occurring 14 days post-immunisation, irrespective of vaccine or subject age. In this small study, a significant transient decline in pre-existing antibodies was observed only in the groups receiving the polysaccharide vaccine and not in the groups receiving HbOC vaccine. Because of the small magnitude of antigen-specific antibody decline and its transient nature, it is unlikely that this observation has clinical significance.

On testing equivalence of three populations.

We consider analysis of clinical trials in which the objective is to show that three populations are equivalent. Equivalence is defined in terms of delta, the maximum difference in population means; a one-sided hypothesis test of delta is considered. We provide the distribution of the maximum pairwise difference in sample means, and we use this distribution to find critical values for tests of size 0.100, 0.050, 0.025, and 0.010. When standard errors are not equal among the three treatments, a simple adjustment is proposed to control the type I error rate. These tests are applied to studying the equivalence of three binomial proportions. Test-based confidence intervals are discussed. Two examples illustrate the proposed methods.