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Biomedical subjects

Stan L Block

Publications and source records attributed to Stan L Block.

16 recordsLinked to original sources
PubMed2007

Efficacy, immunogenicity, and safety of a pentavalent human-bovine (WC3) reassortant rotavirus vaccine at the end of shelf life.

BACKGROUND: Rotavirus is the leading cause of dehydrating acute gastroenteritis in infants worldwide. Previous studies of a live pentavalent human-bovine reassortant rotavirus vaccine have shown it to be efficacious across a range of potencies. OBJECTIVE: Our goal was to evaluate the efficacy, immunogenicity, and safety of pentavalent rotavirus vaccine at the end of shelf life in healthy infants. PATIENTS AND METHODS: During 2002-2004, 1312 healthy infants approximately 6 to 12 weeks old from the United States (47%) and Finland (53%) were randomly assigned to receive 3 oral doses of vaccine (vaccine at approximately 1.1 x 10(7) infectious U per dose) or placebo approximately 4 to 10 weeks apart. Infants were to be followed for acute gastroenteritis through 1 rotavirus season after vaccination and for adverse events postvaccination. RESULTS: Three doses of pentavalent rotavirus vaccine at the end of shelf life demonstrated efficacy against rotavirus gastroenteritis caused by human G-serotypes included in the vaccine (G1-G4). Efficacy against severe rotavirus gastroenteritis was 100%, and efficacy against any rotavirus gastroenteritis regardless of severity was 72.5%. A threefold rise in G1 serum neutralizing was observed in 57% and in anti-rotavirus immunoglobulin A in 96% of pentavalent rotavirus vaccine recipients. No statistically significant increase in vomiting, diarrhea, or irritability was observed among pentavalent rotavirus vaccine recipients compared with placebo recipients within the 7-day period from each dose. A statistically significant increase in fevers (> or = 100.5 degrees F, rectal equivalent) was observed among pentavalent rotavirus vaccine recipients compared with placebo recipients after dose 1. CONCLUSIONS: This pentavalent human-bovine rotavirus vaccine was generally well tolerated, efficacious, and immunogenic at the end of shelf life.

Acute Disease↗
PubMed2006

Comparative tolerability, safety and efficacy of tablet formulations of twice-daily clarithromycin 250 mg versus once-daily extended-release clarithromycin 500 mg in pediatric and adolescent patients.

Clarithromycin is widely used to treat respiratory tract and superficial skin infections in pediatric and adult populations. Using clinical endpoints and 7-day therapy, we compared the efficacy of clarithromycin 250 mg tablets given twice daily versus clarithromycin 500 mg extendedrelease tablets given once daily in ambulatory children and adolescents 6 to 16 years old. Of the 199 evaluable patients, 124 were infected with group A streptococcal pharyngitis, 39 with sinusitis, 21 with ambulatory pneumonia, and 15 with superficial skin infections. The overall cure rate exceeded 90% for each treatment group. Discontinuation rates and adverse events were 4.5% and 24.6%, respectively.

Adolescent↗
PubMed2006

Efficacy, tolerability, and parent reported outcomes for cefdinir vs. high-dose amoxicillin/clavulanate oral suspension for acute otitis media in young children.

OBJECTIVES: To compare efficacy, tolerability, and parental satisfaction of cefdinir and high-dose amoxicillin/clavulanate oral suspensions given to young children with non-refractory acute otitis media (AOM) based on clinical endpoints and outcomes measures. RESEARCH DESIGN AND METHODS: This was an investigator-blinded, multicenter study in which 318 children 6 months through 6 years of age with a clinical diagnosis of AOM were randomized to receive 10 days of either cefdinir (14 mg/kg divided BID) or high-dose amoxicillin/clavulanate (90/6.4 mg/kg divided BID). MAIN OUTCOME MEASURES: Investigators evaluated clinical response at an end-of-therapy (EOT) office visit conducted on day 12-15. Outcomes of satisfaction, tolerability, and adherence were also assessed at that visit using an Otitis Parent Questionnaire. RESULTS: The treatment groups were similar at baseline with respect to patient demographics. At the EOT visit, for cefdinir and amoxicillin/clavulanate, respectively, intent-to-treat (ITT) clinical cure rates were 82% (129/158) and 85% (134/158) (p = 0.547; 95% confidence interval [CI] -11.7 to 5.4) and per-protocol cure rates were 82% (123/150) and 90% (129/143) (p = 0.045; 95% CI -16.4 to 0.0). This difference was driven primarily by reduced cefdinir response in patients with recurrent AOM (p = 0.010) and those younger than 24 months (p = 0.039). Comparing cefdinir with amoxicillin/clavulanate, parents more often reported significantly better ease of use (89% vs. 57%; p < 0.0001), better taste (85% vs. 39%; p < 0.0001), and better adherence (at least 95% of doses) (82% vs. 61%; p < 0.0001). Diarrhea/loose stools were more common in the amoxicillin/clavulanate group than in the cefdinir group (28% vs. 18%, respectively; p = 0.0341). One patient in the cefdinir group and eight patients in the amoxicillin/clavulanate group withdrew from the study prematurely due to at least one adverse event (p = 0.0364). Study limitations included assessment of clinical recurrence by telephone call rather than office visit, exclusion of children with refractory AOM, and no assessment of middle ear microbiology. CONCLUSIONS: Among young children with non-refractory AOM, cefdinir was as efficacious as high-dose amoxicillin/clavulanate in the ITT group, but somewhat less effective in per-protocol analysis. From the parental perspective, cefdinir was easier to administer, had a better taste, caused less diarrhea, and resulted in higher treatment adherence than high-dose amoxicillin clavulanate.

Acute Disease↗
PubMed2006

Comparison of the immunogenicity and reactogenicity of a prophylactic quadrivalent human papillomavirus (types 6, 11, 16, and 18) L1 virus-like particle vaccine in male and female adolescents and young adult women.

OBJECTIVE: Prophylactic vaccination of 16- to 23-year-old females with a quadrivalent human papillomavirus (types 6, 11, 16, 18) L1 virus-like particle vaccine has been shown to prevent type-specific human papillomavirus infection and associated clinical disease. We conducted a noninferiority immunogenicity study to bridge the efficacy findings in young women to preadolescent and adolescent girls and boys, who represent a primary target for human papillomavirus vaccination. METHODS: We enrolled 506 girls and 510 boys (10-15 years of age) and 513 females (16-23 years of age). Participants were vaccinated on day 1, at month 2, and at month 6, and serology testing was performed on day 1 and at months 3 and 7 on blinded samples. Neutralizing antibody concentrations were determined using type-specific immunoassays and summarized as geometric mean titers and seroconversion rates. Vaccine tolerability also was assessed. RESULTS: By month 7, seroconversion rates were > or = 99% for all 4 human papillomavirus types in each group. By month 7, compared with women, anti-human papilloma virus geometric mean titers in girls or boys were noninferior and were 1.7- to 2.7-fold higher. Most (> 97%) injection-site adverse events were mild to moderate in intensity. Significantly more boys (13.8%) and girls (12.8%) than women (7.3%) reported fevers > or = 37.8 degrees C within 5 days of vaccination. Most (96.4%) fevers were mild (< 39 degrees C). CONCLUSIONS: Noninferior immunogenic responses to all 4 human papillomavirus types in the quadrivalent vaccine permit the bridging of efficacy data that were generated in young women to girls. The results in boys lend support for the implementation of gender-neutral human papillomavirus vaccination programs. This vaccine generally was well tolerated.

Adolescent↗
PubMed2005

A comparison of 5 days of therapy with cefdinir or azithromycin in children with acute otitis media: a multicenter, prospective, single-blind study.

BACKGROUND: Short-course therapy for acute otitis media (AOM) improves adherence and may reduce secondary bacterial resistance. METHODS: In this multicenter, prospective, investigator-blinded study, patients between the ages of 6 months and 6 years with a clinical diagnosis of AOM were randomized to receive cefdinir oral suspension 7 mg/kg q12h for 5 days or azithromycin oral suspension 10 mg/kg once daily on day 1 and 5 mg/kg once daily on days 2 through 5. Clinical response was assessed at the end-of-therapy (EOT) visit (days 7-9) and the follow-up visit (days 20-25). RESULTS: Three hundred fifty-seven patients were enrolled in the study. The treatment groups were similar at baseline with respect to demographic characteristics (mean [SD] age, 3.0 [1.7] years; 55% male), incidence of bilateral AOM (45%), and presenting signs and symptoms. The majority of evaluable children (77%) had previously received conjugated heptavalent pneumococcal vaccine (PCV7) against Streptococcus pneumoniae. At the EOT visit, clinical cure rates were comparable for cefdinir and azithromycin (87% [151/174] and 85% [149/176], respectively; 95% CI, -5.5 to 9.8). In addition, clinical cure rates at the EOT visit in the children who had been vaccinated with PCV7 were comparable between cefdinir and azithromycin (86% vs 83%; 95% CI, -6.5 to 11.8). No significant difference in clinical cure rates was observed at the follow-up visit (76% and 86%; 95% CI, -18.9 to 0.0). Parental satisfaction was similar between treatment groups with regard to ease of use, taste, compliance, health care resource utilization, and missed days of work and day-care. Both antibiotics were well tolerated; diarrhea and abnormal stools were the most common antibiotic-related adverse events (< or = 7% each). CONCLUSIONS: Short courses (5 days) of therapy with cefdinir or azithromycin were comparable in these children with AOM based on clinical end points, parental preferences, and health care utilization.

Acoustic Impedance Tests↗
PubMed2004

Efficacy of ofloxacin otic solution once daily for 7 days in the treatment of otitis externa: a multicenter, open-label, phase III trial.

BACKGROUND: Otitis externa (OE) is an infection of the external auditory canal that is typically treated with topically applied broad-spectrum antibiotics. Twice-daily topical treatment with ofloxacin otic 0.3% solution for 10 days has been reported to be as effective and well tolerated as the standard of care, neomycin sulfate/polymyxin B sulfate/hydrocortisone solution administered 4 times daily for 10 days. OBJECTIVE: This study evaluated the efficacy and safety profile of 7 days of a once-daily regimen of ofloxacin otic 0.3% solution in the treatment of OE. METHODS: This multicenter, open-label, Phase III study was conducted from June 12, 2002, to October 14, 2002. Eligible patients were aged > or = 6 months and had OE of <2 weeks' duration with moderate to severe edema and tenderness involving 1 or both ears and sufficient exudate for microbiologic culture. Ofloxacin otic solution was instilled once daily for 7 days (5 drops for children aged 6 months to <13 years, 10 drops for adolescents/adults aged > or = 13 years). Assessments were conducted at the end-of-treatment visit and 7 to 10 days later (the test-of-cure visit). Medication was supplied free of charge to study participants who incurred no costs for physician visits. RESULTS: Of 489 patients enrolled at 58 sites in 3 countries, 439 were clinically evaluable (173 children, 266 adolescents/adults; 52 % males, 48% females; 47% Hispanic, 45% white; 5% black, and 3% other). The cure rate among clinically evaluable patients was 91% (95% of children, 88% of adolescents/adults); 68% of patients were cured within 7 days. Forty-three potentially pathogenic strains were isolated from 253 microbiologically evaluable patients. Pseudomonas aeruginosa was isolated from 158 (62%) microbiologically evaluable patients and Staphylococcus aureus from 32 (13%). Eradication rates were 96% overall. No serious adverse events were observed. Minor adverse events were experienced by 15 (3%) of 489 patients included in the safety population. The most common adverse events were pruritus (5 patients), increased earache (4 patients), and application-site reactions (3 patients). Overall mean (SD) adherence to therapy was 98% (11.9). CONCLUSIONS: Ofloxacin otic 0.3% solution administered once daily for 7 days was well tolerated and effective in achieving clinical and microbiologic cure of OE. The compliance rates in this study suggests that this regimen may be better accepted by patients than longer, more repetitive regimens.

Adolescent↗
PubMed2004

Community-wide vaccination with the heptavalent pneumococcal conjugate significantly alters the microbiology of acute otitis media.

BACKGROUND: Community-wide use of conjugated heptavalent pneumococcal vaccine (PCV7) in children <2 years of age could affect the microbiology of acute otitis media (AOM) in vaccinees, particularly for penicillin-nonsusceptible Streptococcus pneumoniae (PNSP). SETTING: Since Summer 2000, 94% of young children cared for by this 7-clinician, pediatric practice in rural central Kentucky received 3 or 4 doses of PCV7 in the first 18 months of life. OBJECTIVE: To determine changes in microbiology of AOM before and after community-wide routine implementation of PCV7. METHODS: Among children 7-24 months old with severe or refractory AOM, we compared 336 AOM isolates from 1992-1998 with 83 AOM isolates from 2000-2003 in children who had received 3 or 4 doses of PCV7. RESULTS: Comparing each cohort (1992-1998 versus 2000-2003), the proportion of S. pneumoniae decreased from 48% to 31% (P = 0.009; relative risk, 0.754; 95% confidence interval, 0.628-0.906), and nontypable Haemophilus influenzae increased from 41% to 56% (P = 0.01; relative risk, 1.87; 95% confidence interval, 1.15-3.04; beta-lactamase-positive, 56% versus 64%, not significant). The proportions of intermediate PNSP and resistant PNSP, respectively, were 16% and 9% versus 13% and 6% pre- and post-PCV7, respectively. Vaccine and vaccine-related serotypes, respectively, comprised 70% and 8% versus 36% and 32% of S. pneumoniae strains (P = 0.003). Post-PCV7, Gram-negative bacteria and beta-lactamase-producing organisms accounted for two-thirds and one-half of all AOM isolates, respectively. DISCUSSION: The overall proportion of S. pneumoniae isolates and vaccine serotypes in AOM were significantly reduced by community-wide use of PCV7 vaccine in our practice. The proportion of Gram-negative bacteria became 2-fold more frequent than S. pneumoniae in AOM in PCV7-vaccinated young children where PCV7 uptake was community-wide and supply was adequate.

Acute Disease↗
PubMed2004

Comparison of five-day cefdinir treatment with ten-day low dose amoxicillin/clavulanate treatment for acute otitis media.

BACKGROUND: Short course beta-lactam antibiotic therapy for acute otitis media (AOM) should improve patient adherence, but it has not been evaluated since the heptavalent pneumococcal conjugate vaccine became routinely used in the United States. METHODS: In a prospective, investigator-blinded, multicenter study, 425 patients, age 6 months-6 years, with a clinical diagnosis of nonrefractory AOM were randomized to receive either 5 days of cefdinir therapy (14 mg/kg divided twice daily) or 10 days of amoxicillin/clavulanate therapy (45/6.4 mg/kg divided twice daily). Clinical response was assessed at end of therapy (2-4 days postantibiotic, respectively) and week 4 (study days 25-28). RESULTS: With no difference in demographics between treatment groups, overall the mean age (+/-SD) was 2.8 +/- 1.8 years, 65% had received conjugated pneumococcal vaccination and 48% had bilateral AOM. The satisfactory clinical response rate at end of therapy was comparable for cefdinir versus amoxicillin/clavulanate (88%, 170 of 194 versus 85%, 164 of 192; 95% CI -4.9, 9.3). Although this must be interpreted with caution, cefdinir showed an apparent trend for higher efficacy than amoxicillin/clavulanate (92%, 72 of 78 versus 77%, 55 of 71; P = 0.019) in a subsample of patients 6-24 months old who had received conjugated pneumococcal vaccination. The incidence of drug-related adverse events was less for cefdinir than for amoxicillin/clavulanate (24%, 50 of 211 versus 38%, 82 of 214; P = 0.0018) CONCLUSION: For children with nonrefractory AOM, based only on clinical endpoints, 5 days of therapy with cefdinir 14 mg/kg divided twice daily was comparable overall with 10 days of therapy with low dose amoxicillin/clavulanate 45/6.4 mg/kg divided twice daily.

Acute Disease↗
PubMed2004

Role of influenza vaccine for healthy children in the US.

Influenza infection is associated with significant morbidity and mortality in adults, but the highest attack rates for influenza regularly occur in children, particularly those in preschool and elementary school. The consequences of influenza in this younger population - increased rate of hospitalization in those younger than 2 years of age and serious associated morbidity - have been underestimated. Children are also the critical link for spreading influenza in the community. Recent data suggest that mass influenza vaccination of healthy children would not only protect recipients, but also may reduce the burden of influenza throughout the community. During the past 3 decades, efforts to control influenza have focused on the use of an injectable trivalent inactivated vaccine (TIV) in high-risk persons. The vaccine is 'safe' and effective, but its acceptance and uptake by patients and healthcare providers have been modest at best. A new intranasal, live-attenuated, trivalent cold-adapted influenza virus vaccine (CAIV-T) [FluMist] is 'safe', well tolerated, immunogenic, and efficacious in preventing influenza illness in healthy children. Compared with TIV, CAIV-T is easier to administer and should be more readily acceptable, particularly for mass immunization campaigns. CAIV-T also induces a broader immune response and has demonstrated protection against at least three different variant influenza strains. This vaccine is particularly well suited for routine immunization of children and thus offers the potential for greatly improved control of influenza. However, the acquisition cost per single dose of FluMist for the 2003-4 season ( approximate, equals 46 US dollars) significantly hampered its uptake both by practitioners and by managed care organizations, even despite a later approximate, equals 25 US dollars rebate offer. For the 2004-5 season, CAIV-T is likely to be only modestly more expensive (average wholesale price: 16.50 US dollars for non-returnable doses, 23 US dollars for returnable doses) than TIV. The practitioner must consider the benefits of FluMist compared with its likely higher vaccine cost and the issues of reimbursement among multiple insurers.

Adolescent↗
PubMed2003

High-dose azithromycin versus high-dose amoxicillin-clavulanate for treatment of children with recurrent or persistent acute otitis media.

Infants and young children, especially those in day care, are at risk for recurrent or persistent acute otitis media (AOM). There are no data on oral alternatives to high-dose amoxicillin-clavulanate for treating AOM in these high-risk patients. In this double-blind, double-dummy multicenter clinical trial, we compared a novel, high-dose azithromycin regimen with high-dose amoxicillin-clavulanate for treatment of children with recurrent or persistent AOM. Three hundred four children were randomized; 300 received either high-dose azithromycin (20 mg/kg of body weight once a day for 3 days) or high-dose amoxicillin-clavulanate (90 mg/kg divided twice a day for 10 days). Tympanocentesis was performed at baseline; clinical response was assessed at day 12 to 16 and day 28 to 32. Two-thirds of patients were aged < or =2 years. A history of recurrent, persistent, or recurrent plus persistent AOM was noted in 67, 18, and 14% of patients, respectively. Pathogens were isolated from 163 of 296 intent-to-treat patients (55%). At day 12 to 16, clinical success rates for azithromycin and amoxicillin-clavulanate were comparable for all patients (86 versus 84%, respectively) and for children aged < or =2 years (85 versus 79%, respectively). At day 28 to 32, clinical success rates for azithromycin were superior to those for amoxicillin-clavulanate for all patients (72 versus 61%, respectively; P = 0.047) and for those aged < or =2 years (68 versus 51%, respectively; P = 0.017). Per-pathogen clinical efficacy against Streptococcus pneumoniae and Haemophilus influenzae was comparable between the two regimens. The rates of treatment-related adverse events for azithromycin and amoxicillin-clavulanate were 32 and 42%, respectively (P = 0.095). Corresponding compliance rates were 99 and 93%, respectively (P = 0.018). These data demonstrate the efficacy and safety of high-dose azithromycin for treating recurrent or persistent AOM.

Acute Disease↗
PubMed2003

Short-course antimicrobial therapy of streptococcal pharyngitis.

While penicillin administered orally or intramuscularly is the least expensive course of pharyngitis treatment, there are many limitations to its use. These include the need for extended treatment (i.e., 10 days) and poor palatability of its liquid formulation and an alarming increase in the rates of failure with standard doses of either IM or oral penicillin. Increasing rates of beta-lactamase-producing normal flora and eradication of protective alpha-streptococci may also play a role in penicillin treatment failure. Thus practitioners may consider switching to amoxicillin in higher doses (up to 40 to 60 mg/kg/day divided twice daily, maximum dose 1 gram twice daily) as first-line therapy (Figure 1), similar to what we have done for acute otitis media. Five-day short-course treatment with cefdinir or cefpodoxime may be suitable alternatives, especially in patients with penicillin hypersensitivity (not anaphylaxis). Concerns with higher costs of these second-line agents and potential for resistance must be balanced with concerns for patient adherence with penicillin treatment and the recent increasing rate of penicillin failures. In light of recent reports regarding the high rate of failure with azithromycin and increasing macrolide resistance, clinicians should prescribe standard doses of this drug for 5 days with caution.

Child↗
PubMed2002

Pneumococcal serotypes from acute otitis media in rural Kentucky.

OBJECTIVE: Acute otitis media (AOM) accounts for most infections caused by, but few data are available regarding the incidence of pneumococcal serotypes recovered from children with AOM in the United States. METHODS: Between January 1992 and March 1998, 777 middle ear pathogens from AOM were obtained from 701 patients by tympanocentesis (84.6%) or by culture of otorrhea (15.4%) from spontaneous perforation or draining tubes. The ambulatory patient population was mostly white and cared for by a sole private pediatric practice in rural Kentucky. RESULTS: Penicillin-nonsusceptible (penicillin MIC > or = 0.1 microg/ml) (PNSP) isolates accounted for 18% [6% resistant PNSP (rPNSP) and 12% intermediate resistant PNSP], and penicillin-susceptible strains accounted for 35% of the pathogens recovered from children with culture-proved AOM. Comparing the frequency of isolates between 1992 and 1993 with those between 1994 and 1998, overall rates of PNSP strains remained remarkably stable (32.2% 37.3%), but intermediate resistant PNSP strains doubled from 14% to 27% ( < 0.01), whereas rPNSP strains fell by one-third. Serotypes 19F (34%), 23F (30%), 6B (26%) and 14 (8%) accounted for nearly all rPNSP isolates. Two cross-reactive serotypes (6A and 19A) not included in the available pneumococcal conjugate vaccine comprised 8.4 and 15% of all serotypes and PNSP serotypes, respectively. Nearly all PNSP strains recovered in children < or =24 months are included in the vaccine serogroups. CONCLUSION: Depending on rates of efficacy and serotype cross-protection, the current pneumococcal conjugate vaccine could potentially protect against most PNSP strains in all ages, particularly in those < or =24 months.

Age Factors↗