Effect of prednisone on response to influenza virus vaccine in asthmatic children.

OBJECTIVE: To evaluate the immunogenicity of the influenza virus vaccine in children receiving short-course (a burst) prednisone therapy for acute asthmatic exacerbations. DESIGN: Prospective cohort study. SETTING: Outpatient pediatric clinic of a military medical center. PATIENTS: Children aged 6 months to 18 years requiring the 1996 influenza virus vaccine were eligible for the study. A total of 58 children were enrolled initially. The control group included 37 asthmatic children requiring less than 900 microg/d of inhaled prednisone and their siblings. The prednisone group included 21 children vaccinated at the beginning of a course of prednisone prescribed to treat an asthma exacerbation. Thirty-one control subjects (84%) and 19 patients in the prednisone group (90%) completed the study. Dropout was due to failure to come in for the postvaccination serum sampling. INTERVENTIONS: All study patients underwent immunization with the 1996-1997 trivalent subvirion influenza virus vaccine (FluShield; Wyeth Laboratories Inc, Marietta, Pa) containing 15-microg hemagglutinin antigens each of A/Texas/36/91 (H1N1) (A/H1), A/Wuhan/359/95 (H3N2)(A/H3), and B/Beijing/184/93 (B). The prednisone cohort received a burst of oral prednisone therapy (2 mg/kg per day for 5 days). MAIN OUTCOME MEASURES: To assess the immunogenicity of the vaccine between both groups, at least a 4-fold rise in titer and end titers of at least 1:40 to each of the 3 antigens were compared. Mean changes in geometric titers to the 3 antigens were also compared. RESULTS: Proportion of patients in each group with at least a 4-fold rise in titer to each of the influenza antigens was as follows: for A/H3N3 antigen, 15 patients (79%) in the prednisone group vs 22 controls (71%) (P = .74); for A/ H1N1 antigen, 16 patients in the prednisone group (84%) vs 20 controls (64%) (P = .20); and for B antigen, 7 patients in the prednisone group (37%) vs 8 controls (26%) (P = .53). Proportion of patients in each group with an end titer of at least 1:40 to each of the antigens was as follows: for A/ H3N2 antigen, 18 patients in the prednisone group (95%) vs 28 controls (90%) (P = .69); for A/H1N1 antigen, 17 patients in the prednisone group (89%) vs 26 controls (84%) (P = .99); and for B antigen, 7 patients in the prednisone group (37%) vs 13 controls (42%) (P = .99). There were also no significant differences between groups in the mean changes in geometric titers to any of the 3 antigens. CONCLUSIONS: Prednisone bursts did not diminish the response of asthmatic children to the 1996 influenza virus vaccine, compared with controls. Children can be effectively vaccinated against influenza virus while they are receiving prednisone therapy bursts for asthmatic exacerbations.

Carriage of penicillin-resistant pneumococci in a military population in Washington, DC: risk factors and correlation with clinical isolates.

To assess the carriage of penicillin-resistant pneumococci (PRP) in our local (military) population, we retrospectively reviewed our laboratory isolates from the period of January 1990 through May 1994 and prospectively obtained nasopharyngeal culture specimens from 179 children during January through May 1994. The incidence of PRP increased from 0% of pneumococcal isolates in 1990 to 36.2% by 1994. Fifty-two of 179 subjects (29%) were carriers of S. pneumonia, and 25 (48%) of them carried PRP; 11 (21.7%) of these isolated were highly resistant to penicillin (MIC, > 1.0 microgram/mL), and 14 (26.9%) were intermediately resistant (MIC, 0.1-1.0 micrograms/mL). Exposure to a health care worker was correlated with pneumococcal carriage (P < .007). Frequent courses of antimicrobial treatment correlated both with carriage of pneumococci (P < .009) and with carriage of PRP (P < .0001). In contrast, antimicrobial prophylaxis was protective against carriage of pneumococci (P < .002). We conclude that there is a high proportion of PRP among carriers of pneumococci in our community, as corroborated by the risk in laboratory isolation of PRP. Children who have had frequent antimicrobial courses are at particular risk.

Age-dependent humoral responses of children to mycobacterial antigens.

In the United States, disseminated infection with environmental mycobacteria, including the Mycobacterium avium complex, is the most common opportunistic bacterial infection seen in AIDS patients. However, the source and relative degree of exposure to environmental mycobacteria during childhood are unknown. To examine the age-related exposure to mycobacteria, we obtained serum samples from 150 children ranging in age from 6 months to 18 years. Each sample was tested against both M. avium (serovar 1) sonic extracts and mycobacterial lipoarabinomannan, using an enzyme-linked immunosorbent assay (ELISA). All serum samples were also subjected to immunoblot analysis with the sonic extract antigen. These studies established that elevated ELISA values (P < 0.0001) and increased immunoblot reactivity (P < 0.0001) against mycobacterial antigens were both associated with increasing age. The seroreactivity differences were most striking when comparing the age groups of children below the age of 6 with the older age groups. Our results suggest that the development of humoral immune responses to mycobacterial antigens in children correlates with increasing age and that there may be an environmental factor predisposing to mycobacterial exposure which is related to advancing age.