Antibody response to Haemophilus influenzae outer membrane protein D, P6, and OMP26 after nasopharyngeal colonization and acute otitis media in children

Development of natural antibodies to 3 nontypeable Haemophilus influenzae (NTHi) outer membrane proteins (D, P6 and OMP26) was prospectively studied in 130 children 6-30 months of age during NP colonization and acute otitis media (AOM). IgG antibody to protein D, P6 and OMP26 increased with age (p<0.001). Serum IgG responses to NP colonization were different for the 3 proteins: protein D responses occurred at a later age than P6, and OMP26 responses were minimal. For all 3 proteins serum antibody levels in the convalescent phase of AOM infection were not as high as after NP colonization. Antibodies to protein D and P6 but not OMP26 were bactericidal.

Simultaneous assay for four bacterial species including Alloiococcus otitidis using multiplex-PCR in children with culture negative acute otitis media

BACKGROUND

The 3 most commonly encountered bacteria in acute otitis media (AOM) are Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. Conventional culture methods detect these pathogens in only 60% to 70% of cases of AOM. Alloiococcus otitidis, another potential pathogen, has often been ignored.

METHODS

Tympanocentesis was performed in 97 children with AOM presenting with a bulging tympanic membrane (TM) producing 170 middle ear fluids (MEFs). S. pneumoniae, H. influenzae, M. catarrhalis, and A. otitidis were isolated in 21%, 32%, 8%, and 0% of MEFs, respectively; no otopathogen was isolated in 29% of MEFs. In nasopharyngeal cultures at the time of AOM diagnosis, 34%, 36%, 17%, and 0% and in oropharyngeal cultures, 7%, 31%, 11%, and 0% grew S. pneumoniae, H. influenzae, M. catarrhalis, and A. otitidis, respectively. No otopathogen was isolated in 23% of nasopharyngeal and 20% of oropharyngeal cultures. Multiplex polymerase chain reaction (PCR) was used to detect DNA of the 4 bacterial species in culture negative samples.

RESULTS

All culture-positive MEF, nasopharyngeal and oropharyngeal samples tested were also multiplex-PCR positive, indicating the reliability of the method. Culture-negative samples of MEF from children with a bulging TM yielded S. pneumoniae, H. influenzae, M. catarrhalis, and A. otitidis DNA in 51%, 35%, 14%, and 32% of MEF, in 45%, 31%, 10%, and 9% of nasopharyngeal and in 31%, 23%, 0%, and 3% of oropharyngeal, respectively. In 9% of the cases A. otitidis DNA was found without detection of a second organism in MEF.

CONCLUSIONS

Conventional culture detected otopathogens in MEF of children with a bulging TM in 71%; using multiplex-PCR, otopathogens were detected in 88% of MEF (P < 0.01). Similar improved detection of otopathogens was noted with nasopharyngeal and oropharyngeal cultures.

Efficacy and safety of besifloxacin ophthalmic suspension 0.6% in children and adolescents with bacterial conjunctivitis: a post hoc, subgroup analysis of three randomized, double-masked, parallel-group, multicenter clinical trials

BACKGROUND

Acute conjunctivitis is the most frequent eye disorder seen by primary care physicians and one that often affects children. Besifloxacin is a new topical fluoroquinolone, the first chlorofluoroquinolone, for the treatment of bacterial conjunctivitis.

OBJECTIVE

To examine the efficacy and safety of besifloxacin ophthalmic suspension 0.6% in patients aged 1-17 years with bacterial conjunctivitis.

METHODS

This was a post hoc analysis of a subgroup of pediatric patients aged 1-17 years who had participated in three previously reported, randomized, double-masked, parallel-group, multicenter, clinical trials evaluating the safety and efficacy of besifloxacin in the treatment of bacterial conjunctivitis. The studies were conducted in a community setting (clinical centers). All three clinical trials included children (aged > or = 1 year) with a clinical diagnosis of bacterial conjunctivitis in at least one eye, based on the presence at baseline of grade 1 or greater purulent conjunctival discharge and conjunctival injection, and pin-hole visual acuity of at least 20/200 in both eyes for verbal patients. Two trials were vehicle controlled; the third trial was comparator controlled (moxifloxacin hydrochloride ophthalmic solution 0.5% as base). In all studies, besifloxacin ophthalmic suspension 0.6% was administered as one drop in the affected eye(s) three times daily, at approximately 6-hourly intervals, for 5 days. The main outcome measures were clinical resolution and microbial eradication at visit 2 (day 4 +/- 1 in one study; day 5 +/- 1 in the other two studies) and visit 3 (day 8 or 9). Data from the two vehicle-controlled studies were combined for the assessments to provide greater statistical power.

RESULTS

This analysis included 815 pediatric patients aged 1-17 years (447 with culture-confirmed bacterial conjunctivitis). Clinical resolution was significantly greater (p < 0.05) in the besifloxacin group than in the vehicle group at both visit 2 (53.7% vs 41.3%) and visit 3 (88.1% vs 73.0%). Similarly, microbial eradication was significantly higher with besifloxacin than with vehicle at visit 2 (85.8% vs 56.3%) and visit 3 (82.8% vs 68.3%). No significant differences in clinical resolution and microbial eradication were noted between besifloxacin and moxifloxacin. Besifloxacin was well tolerated, with similar incidences of adverse events in the besifloxacin, vehicle, and moxifloxacin groups.

CONCLUSION

Besifloxacin ophthalmic suspension 0.6% was shown to be safe and effective for the treatment of bacterial conjunctivitis in children and adolescents aged 1-17 years.

Booster vaccinations: can immunologic memory outpace disease pathogenesis?

Almost all current vaccines work by the induction of antibodies in serum or on the mucosa to block adherence of pathogens to epithelial cells or interfere with microbial invasion of the bloodstream. However, antibody levels usually decline after vaccination to undetectable amounts if further vaccination does not occur. Persistence of vaccine-induced antibodies usually goes well beyond the time when they should have decayed to undetectable levels because of ongoing "natural" boosting or other immunologic mechanisms. The production of memory B and T cells is of clear importance, but the likelihood that a memory response will be fast enough in the absence of a protective circulating antibody level likely depends on the pace of pathogenesis of a specific organism. This concept is discussed with regard to Haemophilus influenzae type b, Streptococcus pneumoniae, and Neisseria meningitidis; hepatitis A and B; diphtheria, tetanus, and pertussis; polio, measles, mumps, rubella, and varicella; rotavirus; and human papilloma virus. With infectious diseases for which the pace of pathogenesis is less rapid, some individuals will contract infection before the memory response is fully activated and implemented. With infectious diseases for which the pace of pathogenesis is slow, immune memory should be sufficient to prevent disease.

Breast-feeding is associated with a reduced frequency of acute otitis media and high serum antibody levels against NTHi and outer membrane protein vaccine antigen candidate P6

Nontypeable Haemophilus influenzae (NTHi) causes acute otitis media (AOM) in infants. Breast-feeding protects against AOM and/or nasopharyngeal (NP) colonization; however, the mechanism of protection is incompletely understood. Children with AOM and healthy children were studied according to feeding status: breastfed,breast/formula fed, or formula fed. Cumulative episodes of AOM, ELISA titers of serum IgG antibodies to whole-cell NTHi and vaccine candidate outer membrane protein P6, bactericidal titers of serum and NP colonization by NTHi were assessed. A lower incidence of AOM was found in breast- versus formula-fed children. Levels of specific serum IgG antibody to NTHi and P6 were highest in breast-fed, intermediate in breast/formula fed, and lowest in formula-fed infants. Serum IgG antibody to P6 correlated with bactericidal activity against NTHi. Among children with AOM, the prevalence of NTHi in the NP was lower in breast- versus nonbreast-fed infants. We conclude that breast-feeding shows an association with higher levels of antibodies to NTHi and P6, suggesting that breast-feeding modulates the serum immune response to NTHi and P6. Higher serum IgG might facilitate protection against AOM and NP colonization in breast-fed children.

Development of a patient-reported outcome measure for children with streptococcal pharyngitis

OBJECTIVE

The objective of this study was to develop a patient-reported outcome measure (Strep-PRO) for assessing symptoms of group A Streptococcus (GAS) pharyngitis from the child's point of view and to present preliminary data on its internal reliability, construct validity, and responsiveness.

METHODS

We selected 8 symptoms for inclusion in the Strep-PRO. We used the Strep-PRO to assess improvement in children who were aged 5 to 15 years and had confirmed GAS pharyngitis. Children completed the scale at study visits and as a diary at home. To evaluate internal reliability, we examined correlations between the items on the scale. To evaluate construct validity, we examined the correlation at entry between Strep-PRO scores and scores on other, previously validated measures of pain and functional status. To evaluate responsiveness, we examined the change in score from enrollment to follow-up. The correlation between the Strep-PRO score and parental assessment of symptoms was also evaluated.

RESULTS

A total of 131 children were enrolled; 113 returned completed diaries. The internal reliability of the scale was high. The magnitude of correlations between Strep-PRO scores and other measures of pain and functional status ranged from 0.39 to 0.63. The responsiveness of the Strep-PRO was very good. The overall level of agreement between child Strep-PRO scores and parental assessment of symptoms was 0.57.

CONCLUSIONS

The scale seems to measure effectively both pain and overall functional status in children with GAS pharyngitis. These data support the use of Strep-PRO as a measure of outcome in future clinical trials.

Mercury levels in premature and low birth weight newborn infants after receipt of thimerosal-containing vaccines

OBJECTIVE

We conducted a population-based pharmacokinetic study to assess blood levels and elimination of mercury after vaccination of premature infants born at > or =32 and <37 weeks of gestation and with birth weight > or =2000 but <3000 g.

STUDY DESIGN

Blood, stool, and urine samples were obtained before vaccination and 12 hours to 30 days after vaccination from 72 premature newborn infants. Total mercury levels were measured by atomic absorption.

RESULTS

The mean +/- standard deviation (SD) birth weight was 2.4 +/- 0.3 kg for the study population. Maximal mean +/- SD blood mercury level was 3.6 +/- 2.1 ng/mL, occurring at 1 day after vaccination; maximal mean +/- SD stool mercury level was 35.4 +/- 38.0 ng/g, occurring on day 5 after vaccination; and urine mercury levels were mostly nondetectable. The blood mercury half-life was calculated to be 6.3 (95% CI, 3.85 to 8.77) days, and mercury levels returned to prevaccination levels by day 30.

CONCLUSIONS

The blood half-life of intramuscular ethyl mercury from thimerosal in vaccines given to premature infants is substantially shorter than that of oral methyl mercury in adults. Because of the differing pharmacokinetics, exposure guidelines based on oral methyl mercury in adults may not be accurate for children who receive thimerosal-containing vaccines.

Variations in amoxicillin pharmacokinetic/pharmacodynamic parameters may explain treatment failures in acute otitis media

Pharmacokinetic/pharmacodynamic (PK/PD) modeling and Monte Carlo simulations suggest that amoxicillin should rarely fail as therapy for Streptococcus pneumoniae and Haemophilus influenzae acute otitis media (AOM) infections except when the S. pneumoniae are highly penicillin resistant or the H. influenzae are beta-lactamase producing. However, important and not infrequent exceptions to this expectation have been described. The objective of this review was to define the biologic variations in amoxicillin PK/PD parameters for the treatment of AOM in children and assess whether these variations could explain why the commonly employed amoxicillin PK/PD model is imperfect in predicting outcome for every patient in this clinical setting. To this end, a literature search of MEDLINE (1966-2006) and EMBASE (1974-2006) was conducted to identify studies that evaluated ampicillin or amoxicillin intestinal absorption, serum concentrations, and/or middle ear fluid (MEF) concentrations. Analysis of studies identified for review showed that the intestinal bioavailability of amoxicillin depends on passive diffusion and a saturable 'pump' mechanism that produces variable serum concentrations of the antibacterial agent. Indeed, substantial differences from patient to patient in serum (5- to 30-fold) and MEF (up to 20-fold) concentrations of amoxicillin occur following oral administration, and 15-35% of children have no detectable amoxicillin in MEF. These findings suggest that variability in PK/PD parameters may impact amoxicillin concentrations in serum and MEF, possibly explaining some AOM treatment failures.

Novel type of Streptococcus pneumoniae causing multidrug-resistant acute otitis media in children

A new multidrug-resistant strain of serotype 19A has been characterized in upstate New York.

After our recent discovery of a Streptococcus pneumoniae 19A “superbug” (Legacy strain) that is resistant to all Food and Drug Administration–approved antimicrobial drugs for treatment of acute otitis media (AOM) in children, other S. pneumoniae isolates from children with AOM were characterized by multilocus sequence typing (MLST). Among 40 isolates studied, 16 (40%) were serotype 19A, and 9 (23%) were resistant to multiple antimicrobial drugs. Two others had unreported sequence types (STs) that expressed the 19A capsule, and 8 (88%) of the 9 multidrug-resistant strains were serotype 19A, including the Legacy strain with the new ST-2722. In genetic relatedness, ST-2722 belonged to a cluster of reported strains of S. pneumoniae in which all strains had 6 of the same alleles as ST-156. The multidrug-resistant strains related to ST-156 expressed different capsular serotypes: 9V, 14, 11A, 15C, and 19F.

Mucosal vaccination with a multicomponent adenovirus-vectored vaccine protects against Streptococcus pneumoniae infection in the lung

Streptococcus pneumoniae is a major bacterial respiratory pathogen. Current licensed pneumococcal polysaccharide and polysaccharide-protein conjugate vaccines are administered by an intramuscular injection. In order to develop a new-generation vaccine that can be administered in a needle-free mucosal manner, we have constructed early 1 and 3 gene regions (E1/E3) deleted, replication-defective adenoviral vectors encoding pneumococcal surface antigen A (PsaA), the N-fragment of pneumococcal surface protein A (N-PspA), and the detoxified mutant pneumolysin (PdB) from S. pneumoniae strain D39. Intranasal vaccination with the three adenoviral vectors (Ad/PsaA, Ad/N-PspA, and Ad/PdB) in mice resulted in robust antigen-specific serum immunoglobulin G responses, as demonstrated by an enzyme-linked immunosorbent assay. In addition, nasal mucosal vaccination with the combination of the three adenoviral vectors conferred protection against S. pneumoniae strain D39 colonization in mouse lungs. Taken together, these data demonstrate the feasibility of developing a mucosal vaccine against S. pneumoniae using recombinant adenoviruses for antigen delivery.

A comparison of 2 white blood cell count devices to aid judicious antibiotic prescribing

A low or normal white blood cell (WBC) count is usually associated with viral illnesses. This study evaluated the reliability of a new point-of-care, inexpensive, WBC count device which requires only 10 microL (1 drop) of whole blood from a finger stick to an automated Cell-Dyn counter in a busy office practice setting and assessed its reliability to assist in avoiding antibiotic prescribing. A total of 120 acutely ill children and potential antibiotic recipients were studied from October 2007 to March 2008. The mean WBC count was 7.4x10(9)/L and 8.1x10( 9)/L for the new WBC device and the automated Cell-Dyn counter, respectively. The correlation between the 2 devices was high (r=.988, P=.005). A total of 88 children (73%) did not receive antibiotics and mean WBC was 7.2x10(9)/L. In all, 32 children (27%) received an antibiotic and 1 (3%) returned for a follow-up office visit for the same or a related illness. Of the 88 children with a low blood count who did not receive an antibiotic, 3 (3%) had return visit within 30 days and received an antibiotic. A simple and quick point-of-care WBC count device produces similar results as achievable with a Cell-Dyn counter for total WBCs and may assist in judicious antibiotic prescribing.

Probability of achieving requisite pharmacodynamic exposure for oral beta-lactam regimens against Haemophilus influenzae in children

OBJECTIVE

To define contemporary levels of resistance of Haemophilus influenzae to antibacterials commonly used to treat children for bacterial respiratory infections, and to assess the probability of achieving the requisite pharmacodynamic exposures for regimens against recent respiratory H. influenzae isolates using Monte Carlo simulation.

METHODS

233 H. influenzae isolates obtained from pediatric outpatients with acute otitis media (n = 55), sinusitis (n = 58), or lower respiratory tract infections ( n = 120) from 1 November 2004 to 30 April 2005 were characterized for beta-lactamase production and susceptibility to a panel of 10 beta-lactam antimicrobials. 5000 concentration-time profiles were simulated for US FDA-approved doses of oral amoxicillin, amoxicillin/clavulanic acid, cefpodoxime, cefprozil, ceftibuten, and cefuroxime using pharmacokinetics and weights of 5-year old male children. The probability of attaining free drug concentrations above the minimum inhibitory concentration (MIC) for 50% of the dosing interval (50% fT > MIC) was assessed for each regimen against this population of H. influenzae.

RESULTS

beta-Lactamase production was demonstrated in 67 (28.8%) of the H. influenzae isolates and varied by isolation site (38% acute otitis media, 36% sinusitis, and 21% lower respiratory tract infections). Regarding susceptibility, the rank order of the tested antimicrobials was ceftriaxone = cefixime (100%) > cefpodoxime (99.6%) > ceftibuten = amoxicillin/clavulanic acid (99.1%) > cefdinir (98.7%) > cefuroxime (97.4%) > cefprozil (93.1%) > cefaclor (92.3%) > amoxicillin (63.1%). The most active agents based on pharmacodynamic assessment (50% fT > MIC) were cefpodoxime (98.9%), ceftibuten (95.3%), and high-dose amoxicillin/clavulanic acid (90.4%). Several amoxicillin regimens also achieved a high likelihood of pharmacodynamic target attainment (91.8- 98.6%) when beta-lactamase-positive strains were excluded from the analysis.

CONCLUSION

Against H. influenzae, the antibacterials most likely to achieve optimal in vivo exposures in children are cefpodoxime, ceftibuten, and amoxicillin/clavulanic acid.

Adherence of Streptococcus pyogenes to human epithelial cells is modulated by Haemophilus influenzae

Haemophilus influenzae and Streptococcus pyogenes colonize overlapping regions of the nasopharynx and oropharynx. The effect of 10 H. influenzae strains (5 non-piliated parent strains and 5 piliated daughter strains) on adherence of S. pyogenes to human respiratory epithelial cells was assessed in this study. A 39.6% and 49.0% increase in the number of adherent S. pyogenes was observed in Chang epithelial cells if the cells were already colonized with 2 out of 5 non-piliated strains of H. influenzae (p <0.05). Four out of 5 piliated strains of H. influenzae enhanced the adherence of S. pyogenes to Chang cells by 103.5%, 113.6%, 109.7% (p<0.01) and 53.4% (p<0.05). With A549 epithelial cells, non-piliated strains of H. influenzae did not affect the adherence of S. pyogenes (p>0.05), but a 36.9% (p<0.05), 62.9% (p<0.01) and 32.1% (p<0.05) increase in the number of adherent S. pyogenes was found with 3 out of 5 piliated strains of H. influenzae. These results indicate that increases of S. pyogenes adherence to epithelial cells may be modulated species-specifically by H. influenzae, especially by piliated H. influenzae.

Pathogens causing recurrent and difficult-to-treat acute otitis media, 2003-2006

This study sought to determine the microbiology of recurrent acute otitis media (AOM) and AOM treatment failure (AOMTF) in the context of widespread use of heptavalent pneumococcal conjugate vaccine (PCV7). In this retrospective cohort study, 244 AOM isolates obtained by tympanocentesis during 3 respiratory seasons--2003-2004 (n = 126), 2004-2005 (n = 52), 2005-2006 (n = 66)--from three geographically diverse pediatric populations were compared. Most isolates were from children less than 2 years old, who had received PCV7. For the 3 seasons the proportion of Streptococcus pneumoniae isolates was 35%, 35%, and 46% and for Haemophilus influenzae was 55%, 58%, and 39%, respectively (change in trend, P = .09). A total of 37%, 39%, and 50% of S. pneumoniae were penicillin nonsusceptible (PNSP) and 48%, 67%, and 50% of H. influenzae produced beta-lactamase, respectively. Although H. influenzae remains the most frequently isolated pathogen in children with AOMTF or recurrent AOM, S. pneumoniae that are PNSP are reemerging as important organisms.

Frequency of symptomatic relapses of group A beta-hemolytic streptococcal tonsillopharyngitis in children from 4 pediatric practices following penicillin, amoxicillin, and cephalosporin antibiotic treatment

The objective was to determine the frequency of early symptomatic relapses following antibiotic treatment for group A beta-hemolytic streptococcal (GABHS) tonsillopharyngitis in children from Rochester, New York; Houston, Texas; Spokane, Washington; and Los Angeles, California (2004--2006). The study included 4278 patients. The proportion with a bacteriologic relapse of GABHS tonsillopharyngitis within 1 to 5 days of completing a 10-day treatment course was 8% (penicillin and bicillin), 6% (amoxicillin), 2% (first-generation cephalosporin), and 1% (second-generation and third-generation cephalosporin; P = .0001); symptomatic relapses occurred within 6 to 20 days after completion of therapy in 16%, 14%, 9%, and 7% of cases (P = .0001). Cases from New York and Washington had higher penicillin or amoxicillin failure rates than cases from Texas and California. The frequency of symptomatic relapses of GABHS tonsillopharyngitis, therefore, differs according to the antibiotic treatment selected; the trend for such relapses being penicillin or amoxicillin > cephalosporins although geographic differences may occur.

Comparison of study designs for acute otitis media trials

BACKGROUND

A framework for evaluating the efficacy of antibiotics in development as well as those currently approved for acute otitis media (AOM) is needed.

OBJECTIVE

Review strengths and limitations of various antibiotic trial designs and their outcome measures.

METHODS

A review of 157 published trials involving 36,710 subjects for the treatment of AOM.

RESULTS

AOM trials have three designs: (1) clinical, clinical diagnosis and assessment of outcomes; (2) single tympanocentesis, microbiologic diagnosis (by middle ear fluid culture) and clinical assessment of outcomes; and (3) double tympanocentesis, microbiologic diagnosis and microbiologic outcome assessment. Identifiable strengths and limitations of each design are reviewed. Case definitions for entry of children in trials of AOM vary widely. The lack of stringent diagnostic criteria in a clinical design allows for inclusion of a significant proportion of children with a non-bacterial etiology (i.e., viral AOM or otitis media with effusion). Tympanocentesis increases diagnostic accuracy at study entry; however, the procedure is confounding because of its potentially therapeutic benefit and the procedure is not performed in a uniform manner. A second tympanocentesis allows a high sensitivity to detect microbiologic eradication, but it does not correlate with clinical outcomes in half of the cases. The timing of outcome assessment also varies widely among trials.

CONCLUSIONS

Improved clinical diagnosis criteria for AOM are needed to enhance specificity; emphasis on a bulging tympanic membrane has the best evidence base. Tympanocentesis within study designs has merits. At study entry it assures diagnostic accuracy but may alter outcomes and it is useful to document microbiologic outcomes but lacks specificity for clinical outcomes. For all designs, test of cure assessment 2-7 days after completion of therapy seems most appropriate.

Improving vaccine delivery using novel adjuvant systems

Adjuvants have been common additions to vaccines to help facilitate vaccine delivery. With advancements in vaccine technology, several adjuvants which activate immune specific responses have emerged. Available data show these adjuvants elicit important immune responses in both healthy and immunocompromised populations, as well as the elderly. Guidelines for the use and licensure of vaccine adjuvants remain under discussion. However, there is a greater understanding of the innate and adaptive immune response, and the realization of the need for immune specific adjuvants appears to be growing. This is a focused review of four adjuvants currently in clinical trial development: ASO4, ASO2A, CPG 7907, and GM-CSF. The vaccines including these adjuvants are highly relevant today, and are expected to reduce the disease burden of cervical cancer, hepatitis B and malaria.

Mercury levels in newborns and infants after receipt of thimerosal-containing vaccines

OBJECTIVES

Thimerosal is a mercurial preservative that was widely used in multidose vaccine vials in the United States and Europe until 2001 and continues to be used in many countries throughout the world. We conducted a pharmacokinetic study to assess blood levels and elimination of ethyl mercury after vaccination of infants with thimerosal-containing vaccines.

METHODS

Blood, stool, and urine samples were obtained before vaccination and 12 hours to 30 days after vaccination from 216 healthy children: 72 newborns (group 1), 72 infants aged 2 months (group 2), and 72 infants aged 6 months (group 3). Total mercury levels were measured by atomic absorption. Blood mercury pharmacokinetics were calculated by pooling the data on the group and were based on a 1-compartment first-order pharmacokinetics model.

RESULTS

For groups 1, 2, and 3, respectively, (1) mean +/- SD weights were 3.4 +/- 0.4, 5.1 +/- 0.6, and 7.7 +/- 1.1 kg; (2) maximal mean +/- SD blood mercury levels were 5.0 +/- 1.3, 3.6 +/- 1.5, and 2.8 +/- 0.9 ng/mL occurring at 0.5 to 1 day after vaccination; (3) maximal mean +/- SD stool mercury levels were 19.1 +/- 11.8, 37.0 +/- 27.4, and 44.3 +/- 23.9 ng/g occurring on day 5 after vaccination for all groups; and (4) urine mercury levels were mostly nondetectable. The blood mercury half-life was calculated to be 3.7 days and returned to prevaccination levels by day 30.

CONCLUSIONS

The blood half-life of intramuscular ethyl mercury from thimerosal in vaccines in infants is substantially shorter than that of oral methyl mercury in adults. Increased mercury levels were detected in stools after vaccination, suggesting that the gastrointestinal tract is involved in ethyl mercury elimination. Because of the differing pharmacokinetics of ethyl and methyl mercury, exposure guidelines based on oral methyl mercury in adults may not be accurate for risk assessments in children who receive thimerosal-containing vaccines.

Bacterial eradication rates with shortened courses of 2nd- and 3rd-generation cephalosporins versus 10 days of penicillin for treatment of group A streptococcal tonsillopharyngitis in adults

In a meta-analysis of 5 randomized controlled trials involving 1030 adults, the likelihood of bacteriologic eradication in the treatment of group A beta-hemolytic streptococcal (GAS) tonsillopharyngitis with 5 days of select cephalosporins (cefpodoxime, cefuroxime, cefotiam, and cefdinir) was noninferior to 10 days of penicillin (odds ratio, 1.46; 95% confidence interval, 0.96-2.22, P = 0.08).

Emergence of a multiresistant serotype 19A pneumococcal strain not included in the 7-valent conjugate vaccine as an otopathogen in children

CONTEXT

Concern has been raised about the possible emergence of a bacterial strain that is untreatable by US Food and Drug Administration (FDA)-approved antibiotics and that causes acute otitis media (AOM) in children.

OBJECTIVE

To monitor continuing shifts in the strains of Streptococcus pneumoniae that cause AOM, with particular attention to capsular serotypes and antibiotic susceptibility, following the introduction of a pneumococcal 7-valent conjugate vaccine (PCV7).

DESIGN, SETTING, AND PATIENTS

Prospective cohort study using tympanocentesis to identify S pneumoniae strains that caused AOM in children receiving PCV7 between September 2003 and June 2006. All children were from a Rochester, New York, pediatric practice.

MAIN OUTCOME MEASURE

Determination of serotypes and antibiotic susceptibility of S pneumoniae causing AOM.

RESULTS

Among 1816 children in whom AOM was diagnosed, tympanocentesis was performed in 212, yielding 59 cases of S pneumoniae infection. One strain of S pneumoniae belonging to serotype 19A was a new genotype and was resistant to all antibiotics approved by the FDA for use in children with AOM. This strain was identified in 9 cases (2 in 2003-2004, 2 in 2004-2005, and 5 in 2005-2006). Four children infected with this strain had been unsuccessfully treated with 2 or more antibiotics, including high-dose amoxicillin or amoxicillin-clavulanate and 3 injections of ceftriaxone; 3 had recurrent AOM; and for 2 others, the infection was their first in life. The first 4 cases required tympanostomy tube insertion after additional unsuccessful antibiotic therapies. Levofloxacin was used in the subsequent 5 cases, with resolution of infection without surgery.

CONCLUSION

In the years following introduction of PCV7, a strain of S pneumoniae has emerged in the United States as an otopathogen that is resistant to all FDA-approved antibiotics for treatment of AOM in children.

Protective immunity against botulism provided by a single dose vaccination with an adenovirus-vectored vaccine

Botulinum neurotoxins cause botulism, a neuroparalytic disease in humans and animals. We constructed a replication-incompetent adenovirus encoding a synthesized codon-optimized gene for expression of the heavy chain C-fragment (H(C)50) of botulinum neurotoxin type C (BoNT/C). This recombinant human serotype 5 adenoviral vector (Ad5) was evaluated as a genetic vaccine candidate against botulism caused by BoNT/C in a mouse model. A one-time intramuscular injection with 10(5) to 2 x 10(7)pfu of adenoviral vectors elicited robust serum antibody responses against H(C)50 of BoNT/C as assessed by ELISA. Immune sera showed high potency in neutralizing the active BoNT/C in vitro. After a single dose of 2 x 10(7)pfu adenoviral vectors, the animals were completely protected against intraperitoneal challenge with 100 x MLD(50) of active BoNT/C. The protective immunity appeared to be vaccine dose-dependent. The anti-toxin protective immunity could last for at least 7 months without a booster injection. In addition, we observed that pre-existing immunity to the wild-type Ad5 in the host had no significant influence on the protective efficacy of vaccination. The data suggest that an adenovirus-vectored genetic vaccine is a highly efficient prophylaxis candidate against botulism.

Quality of the Haemophilus influenzae type b (Hib) antibody response induced by diphtheria-tetanus-acellular pertussis/Hib combination vaccines

It has been repeatedly observed that mixing Haemophilus influenzae type b (Hib) conjugate vaccines with acellular pertussis-containing vaccines (diphtheria-tetanus-acellular pertussis [DTPa]) resulted in a reduced magnitude of the anti-polyriboseribitolphosphate antibody response compared to that obtained when Hib vaccines were administered separately and not mixed. Nevertheless, the quality and functionality of the immune responses have been shown to be the same. With the purpose of investigating the quality of the anti-Hib immune responses that are elicited under different vaccination regimens, we report here four primary and booster-based pediatric clinical trials in which Hib vaccine was either mixed with DTPa or diphtheria-tetanus-whole-cell pertussis (DTPw)-based vaccines or was coadministered. Our results show that avidity maturation of the antibodies was lower when primary vaccination involved DTPa mixed with Hib compared to when DTPa and Hib were coadministered. No such difference was observed between mixed and separately administered Hib when associated with DTPa-hepatitis B virus-inactivated poliovirus or DTPw-based vaccines. All different combinations and regimens elicited the same opsonophagocytic and bactericidal activity as well as the same ability to protect in a passive infant rat protection assay. The functional activity of mixed DTPa-based and Hib vaccines was similar to that of mixed DTPw-based/Hib combinations. In conclusion, in vitro and in vivo data as well as postmarketing vaccine effectiveness data attest to the ability of DTPa-based/Hib combination vaccines to effectively prevent Hib-induced disease in children.

Immunogenicity and safety of a combination diphtheria, tetanus toxoid, acellular pertussis, hepatitis B, and inactivated poliovirus vaccine coadministered with a 7-valent pneumococcal conjugate vaccine and a Haemophilus influenzae type b conjugate vaccine

OBJECTIVE

To evaluate the immunogenicity and safety of a diphtheria and tetanus toxoids, acellular pertussis, hepatitis B, and inactivated poliovirus-containing vaccine (DTaP-HepB-IPV) coadministered with pneumococcal 7-valent conjugate vaccine (PCV-7) and Haemophilus influenzae type b vaccine (Hib), with separate vaccines concurrently, or staggered (delayed) administration of PCV-7.

STUDY DESIGN

At 2, 4, and 6 months of age, infants received either DTaP-HepB-IPV plus PCV-7 and Hib (n = 199), separate vaccines (n = 188), or DTaP-HepB-IPV plus Hib with PCV-7 administered 2 weeks later (n = 188). Blood was drawn before and after vaccination. Parents reported symptoms for 4 days after each dose and adverse events throughout the entire study.

RESULTS

Immunogenicity in the Combination Vaccine Group was noninferior to that of the Separate and Staggered Vaccine Groups with respect to seroprotective rates for diphtheria, tetanus, and poliovirus and to geometric mean concentrations for pertussis. Seroprotective rates for HepB and Hib were not different between groups. Seropositivity for PCV-7 was high in all groups. Administration of combination vaccine appeared to be associated with higher rates of irritability, fever > or = 100.4 degrees F (38.0 degrees C) and some local symptoms compared with separate vaccines (exploratory P < .05). No group differences were observed in rates of symptoms for which parents sought medical advice.

CONCLUSIONS

DTaP-HepB-IPV was highly immunogenic and well tolerated when coadministered with Hib and PCV-7 at 2, 4, and 6 months of age.

Symptomatic relapse of group A beta-hemolytic streptococcal tonsillopharyngitis in children

The frequency of symptomatic relapses following various antibiotic treatments for group A beta-hemolytic streptococcal tonsillopharyngitis was evaluated in 1080 pediatric patients. Within 5 days of completing therapy, the rank-order frequency of treatment failures was (1) penicillin, (2) amoxicillin, (3) first-generation cephalosporins, (4) beta-lactamase stable cephalosporins and amoxicillin-clavulanate ( P = .005). Retreatment of symptomatic failures resulted in another symptomatic relapse more often with penicillin than with cephalosporins (P = .02). Clinicians should be aware that the rate of symptomatic failures after antibiotic therapy for group A beta-hemolytic streptococcal tonsillopharyngitis differs by drug and is not an uncommon event.

Use of selected cephalosporins in penicillin-allergic patients: a paradigm shift

Recent analysis of clinical data and a clearer understanding of the role of chemical structure in the development of cross-reactivity indicate that the increased risk of an allergic reaction to certain cephalosporins in penicillin-allergic patients is smaller than previously postulated. Medline and EMBASE databases were searched using the following keywords: cephalosporin, penicillin, allergy, and cross-sensitivity for the years 1960 to 2005. Among 219 articles retrieved, 106 served as source material for this review. A significant increase in allergic reactions to cephalothin, cephaloridine, cephalexin, cefazolin, and cefamandole was observed in penicillin-allergic patients; no increase was observed with cefprozil, cefuroxime, ceftazidime, or ceftriaxone. Clinical challenges, skin testing, and monoclonal antibody studies point to the paramount importance of similarities in side chain structure to predict cross-allergy between cephalosporins and penicillins. First-generation cephalosporins have a modest cross-allergy with penicillins, but cross-allergy is negligible with 2nd- and 3rd-generation cephalosporins. Particular emphasis is placed on the role of chemical structure in determining the risk of cross-reactivity between specific agents.

The evidence base for cephalosporin superiority over penicillin in streptococcal pharyngitis

Current treatment guidelines from the Infectious Diseases Society of America, the American Heart Association, and the American Academy of Pediatrics recommend only oral penicillin V or intramuscular benzathine penicillin G as the drugs of choice for treatment of group A beta-hemolytic streptococcal (GABHS) pharyngitis. Ten-day treatment courses with 1st-generation oral cephalosporins or erythromycin are recommended as suitable alternatives in patients who are allergic to penicillin. Despite these recommendations, oral cephalosporins are used as drugs of choice for many patients with GABHS pharyngitis. Simpler and/or short-course regimens of cephalosporins that have been approved by the Food and Drug Administration offer alternatives with the potential for unchanged patient compliance. Increasing cephalosporin use in patients with GABHS pharyngitis has followed from numerous reports and metaanalyses of cephalosporin superiority over penicillin for bacteriologic eradication and clinical response. This review examines the evidence supporting the use of cephalosporins as a first choice of treatment for many patients with GABHS pharyngitis.

Protection against anthrax by needle-free mucosal immunization with human anthrax vaccine

Human vaccination with BioThrax requires six injections followed by annual boosters. This makes it difficult for the compliance of the immunization program and underscores the need for development of a new and optimized vaccination protocol. Current research aims to demonstrate the proof of concept to develop a needle-free mucosal immunization protocol using a murine anthrax model. A/J mice were immunized with BioThrax via an intranasal route. Sera, saliva, vaginal, and nasal washes were evaluated for protective antigen (PA) specific antibody responses by ELISA. Antigen-specific, antibody-secreting lymphocytes were measured by ELISPOT. Sera neutralization antibody titers were determined by in vitro anthrax lethal toxin (Letx) neutralization assay. Immunized animals were challenged by a lethal dose of Bacillus anthracis Sterne spores to determine the efficacy of the vaccination. Nasal mucosal immunization with BioThrax elicited robust serum and mucosal antibody responses against PA. The antigen specific antibodies neutralized anthrax Letx, as demonstrated by in vitro neutralization assays. Two doses of intranasal BioThrax were sufficient to completely protect A/J mice against challenge with 100xLD50B. anthracis Sterne spores. The data suggests that intranasal administration may be an effective immunization modality for an improved immunization program against anthrax.

Acellular pertussis vaccine boosters combined with diphtheria and tetanus toxoid boosters for adolescents: safety and immunogenicity assessment when preceded by different 5-dose DTaP/DTwP schedules

A sixth dose of tetanus, diphtheria, acellular pertussis (Tdap) vaccine in adolescents might produce a differing reactogenicity and/or immunogenicity response depending on the composition of the 5 prior doses of DTaP or DT-whole cell pertussis (DTwP) vaccine. Reactions and immune responses following receipt of the Sanofi Pasteur (Adacel) and GlaxoSmithKline (Boostrix) Tdap vaccines were assessed in 229 adolescents. No differences were observed for reactions to either Tdap vaccine regardless of the prior DTaP/DTwP vaccination history. Seroprotective levels and antibody concentrations were comparable regardless of prior DTaP/DTwP vaccine history. A sixth sequential dose of Tdap after 5 doses of DTaP appears safe and immunogenic.

An adolescent and adult formulation combined tetanus, diphtheria and five-component pertussis vaccine

Pertussis causes substantial morbidity among adolescents and adults, as well as other persons in contact with affected individuals. In the context of widespread childhood immunization, vaccination of adolescents and adults is a relatively new strategy for reducing the disease in all age groups. ADACEL is a tetanus-diphtheria-acellular pertussis combination vaccine (incorporating pertussis toxoid, filamentous hemagglutinin, pertactin and fimbriae type 2 and 3 antigens) formulated for use in adolescents and adults based on similar products designed for infants and children. ADACEL vaccine is approved for use in Australia, Canada, Germany and the USA, and has been demonstrated to induce robust immune responses and acceptable levels of reactogenicity in clinical trials. Surveillance data from Canada, where ADACEL vaccine has been used in adolescents and adults in conjunction with ongoing childhood vaccination for several years, indicate an enhanced overall reduction in pertussis disease.

Pathogen shifts and changing cure rates for otitis media and tonsillopharyngitis

Pneumococcal conjugate vaccine use has caused a decrease in the incidence of recurrent and refractory acute otitis media in the United States and a shift in the predominant pathogens. Now Haemophilus influenzae is the most commonly isolated organism (about 60% of the total), and more than half the strains make beta-lactamase, rendering them resistant to amoxicillin. Penicillin nonsusceptible pneumococci, the main target of antibiotic therapy in the 1990s, has become a much less common isolate (10%- 25% of the total). These changes impact antibiotic selection for acute otitis media. Penicillin treatment of group A streptococcal tonsillopharyngitis does not meet the minimum United States Food and Drug Administration standards for first-line treatment, which is 85% or greater eradication at the end of therapy. Recent results with amoxicillin suggest its efficacy is also waning. Cephalosporins have the highest bacteriologic and clinical efficacy. This has implications for optimal antibiotic therapy.

The use of tympanocentesis in the diagnosis and management of acute otitis media

Acute otitis media (AOM), when associated with a bulging or full tympanic membrane, has a bacterial etiology in more than 90% of cases. Not infrequently, the organisms present express resistance mechanisms to commonly prescribed antibiotic therapy. Tympanocentesis is a procedure advocated by several national guidelines for use in selected patients not clinically responding to antimicrobial treatment. In this paper we discuss the use of tympanocentesis as a tool to track pathogen shifts and to guide antibiotic selection. We detail the indications for tympanocentesis, compare guidelines endorsing the procedure, and describe how to implement a technique for use in the primary care setting. The pros and cons of using tympanocentesis in clinical trial designs are also presented.

Acellular pertussis vaccine booster combined with diphtheria and tetanus toxoids for adolescents

BACKGROUND

The incidence of pertussis is increasing, especially in adolescents, attributed in part to waning of immunity after childhood immunization. Recently licensed in the United States for use in adolescents, acellular pertussis vaccines will provide an immunogenic and safe option for booster immunization against pertussis.

METHODS

This prospective, randomized, observer-blinded, multicenter, comparative study evaluated the safety and immunogenicity of a vaccine formulated with tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis antigens (Tdap) compared with tetanus and diphtheria toxoids vaccine (Td) for booster immunization in adolescents. There were 4114 healthy adolescents aged 10 to 18 years who completed childhood vaccination against diphtheria, tetanus, and pertussis who were enrolled, randomized, and received study vaccine.

RESULTS

Local and general symptoms were comparable between the Tdap and Td groups. The immune response of Tdap was comparable with Td vaccine for tetanus and diphtheria seroprotection and booster responses. In addition, geometric mean concentrations of antibody to pertussis antigens, pertussis toxoid, filamentous hemagglutinin, and pertactin exceeded the antibody response elicited after infant immunization with diphtheria and tetanus toxoids and acellular pertussis antigens (DTaP) that had proven efficacy against pertussis.

CONCLUSIONS

In adolescents, the studied Tdap was safe and immunogenic and induced pertussis antibodies that were higher than those associated with efficacy in infants.

Cephalosporins can be prescribed safely for penicillin-allergic patients

The widely quoted cross-allergy risk of 10% between penicillin and cephalosporins is a myth. Cephalothin, cephalexin, cefadroxil, and cefazolin confer an increased risk of allergic reaction among patients with penicillin allergy. Cefprozil, cefuroxime, cefpodoxime, ceftazidime, and ceftriaxone do not increase risk of an allergic reaction.

Meningococcal conjugate vaccines

Disease caused by Neisseria meningitidis is associated with high mortality rates and significant sequelae. Polysaccharide meningococcal vaccines have been available for > 20 years, and have been used in travellers to control outbreaks, and in some countries for adolescents entering college, although they provide only a short duration of immunity and do not produce a herd effect. Monovalent and quadrivalent (A, C, Y, W-135) meningococcal conjugate vaccines have recently been licensed and endorsed for use in infants, children, adolescents and adults in various countries. Among the key features of the new meningococcal conjugate vaccines are stimulation of both B cell-dependent and T cell-dependent immune responses, induction of immunological memory and booster effects, longer-term protection, reduction of nasopharyngeal carriage of N. meningitidis, and herd immunity. Large, randomised, double-blind studies in adults, adolescents, children and infants have demonstrated the immunogenicity and safety of the new meningococcal conjugate vaccine formulations.

Acute otitis media: influence of the PCV-7 vaccine on changes in the disease and its management

Studies have shown that most cases of acute otitis media (AOM) are of viral or "no bacteria isolated" origin. In these cases, watchful waiting may be appropriate. This publication addresses presumed bacterial causes of AOM for which antibiotic use may be efficacious.

Metaanalysis of short course antibiotic treatment for group a streptococcal tonsillopharyngitis

OBJECTIVE

To compare bacterial and clinical cure rates in patients with group A streptococcal (GAS) tonsillopharyngitis treated with oral beta-lactam or macrolide antibiotics for 4-5 days versus 10-day comparators.

METHODS

Medline, Embase, reference lists and abstract searches were used to identify available publications. Trials were included if there was bacteriologic confirmation of GAS tonsillopharyngitis, random assignment to antibiotic therapy for a beta-lactam or macrolide antibiotic of a shortened course versus a 10-day comparator and assessment of bacteriologic outcome using a throat culture.

RESULTS

Twenty-two trials involving 7470 patients were included in 4 separate analyses. Trials were grouped by a short course of cephalosporins (n = 14), macrolides (other than azithromycin) (n = 6) and penicillin (n = 2). Cephalosporin trials were further grouped by the comparator, penicillin or the same cephalosporin. Short course cephalosporin treatment was superior for bacterial cure rate compared with 10 days of penicillin [odds ratio (OR), 1.47; 95% confidence interval (CI), 1.06-2.03]. For trials with short course macrolide therapy, OR = 0.79 (95% CI 0.59-1.06) neither the macrolides nor the 10-day comparators. Short course penicillin therapy was inferior in achieving bacterial cure versus 10 days of penicillin, OR = 0.29 (95% CI 0.13-0.63). Clinical cure rates mirrored bacteriologic cure rates.

CONCLUSION

Superior cure rates can be achieved with shortened courses of cephalosporin therapy, but 5 days is inferior to 10 days of penicillin treatment.

Preferred antibiotics for treatment of acute otitis media: comparison of practicing pediatricians, general practitioners, and otolaryngologists

The antibiotic preferences of 2,190 pediatricians (peds) 360 general practitioners (GPs), and 273 otolaryngologists (ENTs) in the United States and concurrence with treatment guideline recommendations for acute otitis media (AOM) for suspected drug-resistant Streptococcus pneumoniae (DRSP) and beta-lactamase-producing Haemophilus influenzae before and after an educational workshop were compared. Peds and GPs preferred amoxicillin/clavulanate high-dose, whereas ENTs preferred higher generation cephalosporins. Before the workshop, endorsement of guideline-recommended antibiotics for treatment of AOM caused by DRSP by Peds, GPs, and ENTs was 80%, 75%, and 78%, respectively, and for Haemophilus influenzae was 73%, 63%, and 84%, respectively. After the workshop concurrence with AOM guideline recommendations for DRSP increased to 96%, 95%, and 97% and for H. influenzae increased to 93%, 94%, and 96% for Peds, GPs, and ENTs, respectively (p<0.0001 for all comparisons). Peds, GPs, and ENTs select appropriate antibiotics for AOM 63-84% of the time. After instruction that provides the rationale for guideline-recommended agents based on pharmacokinetics/pharmacodynamics and double tympanocentesis trials, endorsement of recommended antibiotics significantly improved to >90%.

N-fragment of edema factor as a candidate antigen for immunization against anthrax

The nontoxic N-terminal fragment of Bacillus anthracis edema factor (EF) was evaluated as a candidate antigen in an anthrax vaccine using a replication-incompetent adenoviral vector. An E1/E3 deleted adenovirus (Ad/EFn) encoding the N-terminal region 1-254 amino acids of the edema factor (EFn) was constructed using the native DNA sequence of EFn. Intramuscular immunization three times with 10(8) plaque forming units (pfu)/dose of Ad/EFn in A/J mice resulted in 37% and 57% protection against a subcutaneous challenge with B. anthracis Sterne strain spores at a dosage of 200 x LD50 and 100 x LD50, respectively. EF-specific serum IgG responses (including total IgG, IgG1, and IgG2a isotype titers) were robust in the Ad/EFn immunized animals. Interestingly, anti-EF antibodies cross-reacted with anthrax lethal factor (LF), and had a neutralizing capability against both anthrax lethal toxin (Letx) and edema toxin (Edtx), as demonstrated by in vitro toxin neutralization assays using J774A.1 mouse macrophage and Chinese hamster ovary cell (CHO), respectively. Our data suggest that EF plays a role in eliciting protective immunity against anthrax, and that it should be included in a new generation multi-component subunit vaccine.

Safety and Efficacy of Gatifloxacin Therapy for Children with Recurrent Acute Otitis Media (AOM) and/or AOM Treatment Failure

BACKGROUND

Because of concerns about arthrotoxicity, fluoroquinolones are restricted for use in children. This study describes the safety and efficacy of gatifloxacin when used for treatment of children with recurrent acute otitis media (ROM) or acute otitis media (AOM) treatment failure (AOMTF).

METHODS

We performed an analysis of 867 children included in 4 clinical trials who had ROM and/or AOMTF and were treated with gatifloxacin (10 mg/kg once daily for 10 days).

RESULTS

Gatifloxacin had adverse event rates that were similar overall to those of a comparator antibiotic (amoxicillin-clavulanate), except for increased diarrhea in children <2 years old receiving amoxicillin-clavulanate. There was no evidence of arthrotoxicity, hepatotoxicity, alteration of glucose homeostasis, or central nervous system toxicity acutely or during 1 year follow-up in any child. Regarding efficacy, in 2 noncomparative trials, the gatifloxacin cure rate of AOM was 89% (95% confidence interval [CI], 83%-95%) at the test of cure (TOC) visit, 3-10 days after completion of therapy. In 2 comparative trials of gatifloxacin versus amoxicillin-clavulanate, the efficacy of gatifloxacin was 88% (95% CI, 82%-94%). Gatifloxacin led to better clinical outcomes than amoxicillin-clavulanate for AOMTF (91% vs. 81%; P=.029), for AOMTF and age <2 years old (89% vs. 69%; P=.009), and for severe AOM in children <2 years old (90% vs. 75%; P=.012). Among children with AOMTF previously treated with amoxicillin-clavulanate or ceftriaxone injections, gatifloxacin cure rates were high (88% and 75%, respectively).

CONCLUSIONS

Gatifloxacin appears to be safe for children, with no evidence of producing arthrotoxicity in 867 children exposed to the antibiotic when used as treatment for ROM and AOMTF.

Evolving shifts in otitis media pathogens: relevance to a managed care organization

The microbiological landscape of acute otitis media (AOM) has been relatively constant over the past half century. Because of this stability, empiric management of AOM was a common and efficient practice. Recently, there has been a proportional shift in the microbiology of AOM, bringing the choices for empiric therapy into question. Because of this shift, managed care organizations should review their formularies to ensure that they are structured to include and promote the use of appropriate antibiotics. This article explores the background and events leading up to the shift in AOM microbiology; discusses the clinical consequences and the future implications of the shift, such as increased costs associated with treatment failures, its impact on new vaccines and new-onset AOM and related disease states, such as sinusitis; and describes why these factors should be considered by managed care decision makers in their formulary deliberations.

Meningococcal conjugate vaccine in adolescents and children

Disease caused by Neisseria meningitidis is associated with high mortality rates and significant sequelae. Quadrivalent (A, C, Y, W-135) polysaccharide meningococcal vaccine has been available for more than 20 years, and although used widely for adolescents entering college, it has a number of limitations, including short duration of immunity and lack of a herd effect. A quadrivalent meningococcal conjugate vaccine has recently been licensed and endorsed for use in adolescents 11 to 12 years of age, at age 15, or at college entry. Among the key features of the new meningococcal conjugate vaccine are stimulation of both B-cell-dependent and T-cell-dependent immune responses, induction of immunologic memory and booster effects, long-term protection, reduction of nasopharyngeal carriage of N. meningitidis, and herd immunity. Large randomized, double-blind studies in adolescents and 2- to 10-year olds have demonstrated the immunogenicity as well as the safety and tolerability of the new meningococcal conjugate vaccine formulation.

Combined tetanus, diphtheria, and 5-component pertussis vaccine for use in adolescents and adults

CONTEXT

Increasing reports of pertussis among US adolescents, adults, and their infant contacts have stimulated vaccine development for older age groups.

OBJECTIVE

To assess the immunogenicity and reactogenicity of a tetanus-diphtheria 5-component (pertussis toxoid, filamentous hemagglutinin, pertactin, and fimbriae types 2 and 3) acellular pertussis vaccine (Tdap) in adolescents and adults.

DESIGN, SETTING, AND PARTICIPANTS

A prospective, randomized, modified double-blind, comparative trial was conducted in healthy adolescents and adults aged 11 through 64 years from August 2001 to August 2002 at 39 US clinical centers.

INTERVENTIONS

A single 0.5-mL intramuscular dose of either Tdap or tetanus-diphtheria vaccine (Td).

MAIN OUTCOME MEASURES

Antibody titers to diphtheria and tetanus toxoids for Tdap and Td were measured in sera collected from subsets of adolescents and adults, before and 28 days after vaccination. For pertussis antigens, titers in sera from Tdap vaccinees were assessed vs those from infants who received analogous pediatric diphtheria-tetanus-acellular pertussis vaccine (DTaP) in a previous efficacy trial. Safety was assessed via solicited local and systemic reactions for 14 days and adverse events for 6 months following vaccination.

RESULTS

A total of 4480 participants were enrolled. For both Tdap and Td, more than 94% and nearly 100% of vaccinees had protective antibody concentrations of at least 0.1 IU/mL for diphtheria and tetanus, respectively. Geometric mean antibody titers to pertussis toxoid, filamentous hemagglutinin, pertactin, and fimbriae types 2 and 3 exceeded (by 2.1 to 5.4 times) levels in infants following immunization at 2, 4, and 6 months with DTaP. The incidence of solicited local and systemic reactions and adverse events was generally similar between the Tdap and Td groups.

CONCLUSIONS

This Tdap vaccine elicited robust immune responses in adolescents and adults to pertussis, tetanus, and diphtheria antigens, while exhibiting an overall safety profile similar to that of a licensed Td vaccine. These data support the potential routine use of this Tdap vaccine in adolescents and adults.