Antiviral Pharmacology: A Standardized Patient Case for Preclinical Medical Students

INTRODUCTION

Pharmacology is an important learning topic in preclinical medical education. Simulated patient encounters allow students to apply basic science knowledge in a clinical setting and have been useful in previous studies of pharmacology education. We developed a standardized patient (SP) encounter to reinforce antiviral pharmacology content for first-year medical students.

METHODS

Students were instructed to recommend a medication for shingles during an SP encounter and to answer questions from the SP on mechanism of action and adverse effects. Students then attended a large-group debrief session. Following the activity, students evaluated the exercise through a voluntary survey. For knowledge assessment, students were randomized into two groups to complete three multiple-choice questions either before or after the learning activity.

RESULTS

In 2020 and 2021, 144 and 145 students, respectively, participated. In 2020, there was no significant difference in the proportion of correct answers between the pre- and postsimulation groups (p > .05). In 2021, the postsimulation group significantly outperformed the presimulation group in knowledge of mechanism of action (p < .01) and adverse effects (p < .01), but no difference was seen between the groups regarding medication selection (p = .27). Most learners assessed the instructional design as effective for the tasks assigned.

DISCUSSION

This SP activity provided an opportunity for early medical students to practice integrating antiviral pharmacology knowledge into a patient encounter and was well received by learners. The instructional method offers a clinically relevant approach for reinforcing pharmacology knowledge for preclinical medical students.

Early Pre-clerkship Clinical Skills Assessments Predict Clerkship Performance

INTRODUCTION

Assessment of medical students' clinical skills (CS) remains a challenge. Little is known about early predictors of future CS performance. This study examines the relationship between students' pre-clerkship clinical skills (PCCS) performance and year 3 clerkship performance measures.

METHODS

The authors performed a retrospective analysis of four medical student cohorts who matriculated between 2014 and 2017 and participated in a longitudinal pre-clerkship CS curriculum. A total of 440 students were included in the analyses. Students' clinical skills were assessed through a series of PCCS exams, each consisting of a single standardized patient encounter. First-year PCCS exams assessed history taking, physical examination, professionalism, and communication skills; second-year PCCS exams also assessed clinical documentation and clinical reasoning skills. Evaluators assigned a grade of "satisfactory," "borderline," or "unsatisfactory" for each skill set. Regression analyses compared year 3 performance outcomes between students with one or more "unsatisfactory" or "borderline" PCCS skill set grades and students assessed as "satisfactory" for all PCCS skill set assessments.

RESULTS

Thirty-two percent (n = 140) of the 440 students had at least one borderline or unsatisfactory (US) PCCS skill set grade. These students performed significantly worse on year 3 National Board of Medical Examiner subject exams, workplace-based clinical performance evaluations, and overall year 3 performance compared to students who passed all PCCS exam components. In addition, a higher percentage of students with PCCS performance deficiencies failed the United States Medical Licensing Examination Step 2 CS exam on the first attempt versus students who passed all PCCS exam components.

CONCLUSIONS

PCCS exam performance at our institution aligned with future student performance on multiple year 3 clerkship outcome measures. This pre-clerkship performance data can be used to identify at-risk students who would benefit from additional resources to achieve competency in the clerkship environment and future medical training.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s40670-022-01519-8.

Student, Faculty, and Coach Perspectives on Why Athletes Excel in Medical School: A Qualitative Analysis

Phenomenon Medical schools are tasked with selecting applicants who will excel in a rigorous curriculum and successfully perform as future physicians. While many studies have assessed quantitative prematriculation data for predicting success in medical school, fewer studies have assessed for qualitative prematriculation factors influencing medical school performance. A recent study revealed that medical students with at least one year of varsity level college athletics participation outperformed their peers on United States Medical Licensing board exams and clinical clerkships. The current study sought to explore medical student, medical school faculty, and college coach perspectives about factors explaining why medical students with collegiate athletic experience succeed in medical school. Approach: In 2019, the authors conducted semi-structured interviews with medical students with collegiate athletic experience, medical school faculty with experience educating student athletes, and college coaches with experience training student athletes who matriculated into medical school. The interview transcripts were systematically coded and analyzed for themes using a grounded theory approach. Participants were recruited and interviewed until saturation of data was reached. Findings: Fifteen medical students with collegiate athletic experience, five medical school faculty, and three collegiate coaches participated in the study. Six themes were identified as important factors explaining the academic success of these students in medical school and each of these themes appeared in student, faculty, and coach interviews: goal setting, goal pursuit, and performance appraisal; development of time management, planning, and organizational skills; development of team values and teamwork skills; development of communication and interpersonal skills; acceptance of, coping strategies for, and resilient response to stress and adversity; and prioritization of personal wellness. Participants described meaningful connections between these attributes and skills, suggesting the students' development, transfer, and application of them is interrelated. Insights: In this study, academic success of medical students with collegiate athletic experience was attributed to specific skills and attributes developed during college. The grounded theory life skills transfer model can explain transfer of these attributes and skills from college to the medical school setting. Theoretical frameworks and empirical study findings from the sociology, educational psychology, sports psychology, and medical education literature provide helpful lenses for understanding why these skills and attributes confer success among student athletes in medical school. These findings offer important insights on skill development that may support the academic success of all medical students.

951. Virtually the Same: Our Experience Teaching Abx Before and During the Pandemic

Background

Understanding core principles of empiric antibiotic (abx) therapy is essential for abx stewardship. Pre-pandemic, the “Abx 101” workshop taught students an initial approach to empiric abx. Due to the pandemic, the session became virtual. We hypothesized that the face-to-face version (FTF) would be more effective and more positively reviewed by students compared to the virtual.

Methods

For the FTF, 3 faculty facilitated workshops of 50 3rd year medical students. The intro reviewed the typical microbiota of body areas (or common pathogens for community-acquired disease in sterile spaces). Student small groups were assigned a category of abx coverage (e.g. “MRSA drugs”), and completed a worksheet to identify abx in the assigned category from a reference list of abx. Groups taught back to the class (jigsaw technique) about abx for their respective categories. Next, faculty facilitated a large group discussion in which they matched initial abx therapy for each body area’s typical microbiome or pathogens. Finally, groups presented cases to the class and identified likely diagnosis, most likely organisms, and appropriate empiric abx to target those organisms. For the virtual version, the format was adapted for a 1 hour online interactive session with 1 MD facilitator, 20-25 students, and no breakout groups/jigsaw technique. The content was unchanged other than fewer cases.

Results

26 of 140 (19%) students completed the survey (n=13 FTF, n=13 virtual). An independent-samples t-test compared FTF and virtual overall satisfaction scores. There were no significant differences in satisfaction from the FTF (M=8.54, SD=1.04) and virtual sessions (M=8.62, SD=1.94); t(24)=-.126. p=0.901. 100% of both groups rated the session as quite/extremely relevant to their training and 100% of respondents in both groups deemed the format of the sessions appropriate for the content. In the FTF group, 76% of respondents felt the session was quite/extremely effective for learning about abx spectra of activity, compared to 69% in the virtual group (X2 (1, N = 26) = .195, p = .658).

Conclusion

“Abx 101” was relevant, effective, and formatted well for learning about empiric abx, in FTF and virtual versions. These findings suggest that this curriculum is effective overall and adapts well for in-person and remote learning.

Disclosures

All Authors: No reported disclosures

Simulation: an Innovative Approach to Engaging Preclinical Medical Students with Bioethics

BACKGROUND

Integrating bioethical concepts into preclinical medical school curriculum and engaging early medical learners in bioethics are a challenge.

ACTIVITY

A total of 140 medical students participated in a 2-h simulation activity consisting of a series of standardized patient (SP) encounters.

RESULTS

A total of 41 of 140 students (29%) completed the learner evaluation survey. Ninety-one percent thought that the SP encounter was relevant to their role as a future physician. Ninety-three percent of students rated the exercise as highly effective.

CONCLUSIONS

SP encounters enhance preclinical medical students' engagement with bioethics and provide learners practice applying these concepts to clinically relevant scenarios.

1373. Vaccine Effectiveness and Pneumococcal Serotypes in Pediatric Otitis Media in the Era of Routine 13-valent Pneumococcal Vaccination in the United States

Background

Pneumococcal acute otitis media (AOM) in children due to vaccine related serotypes (St) declined after the introduction of the 13-valent pneumococcal conjugate vaccine (PCV13).

Methods

Patients < 18 years with pneumococcal OM isolates from 2014-2019 from the U S Pediatric Multicenter Pneumococcal Surveillance Group were analyzed for demographics, immunization status, antimicrobial susceptibility and St distribution. p< 0.05 was considered statistically significant. Vaccine effectiveness (VE) was calculated using a standard formula: 1-([PCV13St vaccinated (≥3 PCV13 doses) x Non-PCV13St unvaccinated (0-1 PCV13 doses)]/[PCV13St unvaccinated x Non-PCV13St vaccinated])

Results

646 patients were identified. Patients with PCV13 St were older compared to patients with non-PCV13 serotypes (3.3 vs 1.5 median years, p< 0.0001). Most isolates were from spontaneous drainage (71.4 %) and PE tube placements (26.9%). 36 different Sts were identified; 83.4% of isolates were non-PCV13 Sts; 35B represented 18.3% of all isolates. St 19A decreased over time (p=0.0003). 14% of isolates had penicillin MIC ≥2 µg/ml and 2.4% had ceftriaxone MIC >1 µg/ml. (Figure) 633 patients had known vaccine status. VE was 86.4% (Table).

Table.

Conclusion

Non-PCV13 Sts caused most pneumococcal OM. St35B was the most common St. St 19A decreased as a cause of otitis. In this study the VE of≥3 PCV13 doses was 86% for pneumococcal OM.

Disclosures

Tina Q. Tan, MD, Pfizer (Grant/Research Support, Other Financial or Material Support, Chair, DMSB for PCV20 vaccine) Pia S. Pannaraj, MD, MPH, AstraZeneca (Grant/Research Support)Pfizer (Grant/Research Support)Sanofi Pasteur (Advisor or Review Panel member) Sheldon L. Kaplan, MD, Allergan (Research Grant or Support)Pfizer (Grant/Research Support)

The Zombie Virus Pandemic: An Innovative Simulation Integrating Virology, Population Health, and Bioethics for Preclinical Medical Students

Introduction

Understanding population health in the context of infectious disease outbreaks is an important physician competency. However, identifying effective ways to engage early medical students in this content remains a challenge. We designed an innovative pandemic simulation for first-year medical students utilizing the pop culture theme of zombies.

Methods

This 2.5-hour simulation was conducted in 2018 and 2020 during students' virology course. Student teams collected and analyzed data to formulate hypotheses for the source pathogen. The teams completed reports explaining their diagnostic hypotheses, infection containment recommendations, and resource allocation recommendations. Learners completed an evaluation of the simulation through an online survey. Responses were analyzed using descriptive statistics; narrative responses were analyzed qualitatively for themes. A content analysis was performed on students' reports.

Results

Two hundred eighty-four medical students participated in this activity. Nearly all respondents agreed that the small-group format (98%, 2018 and 2020) and pace and duration (92%, 2018; 94%, 2020) were appropriate and that the activity was intellectually stimulating (97%, 2018; 96%, 2020). Learner engagement measures were high (90%-97%, 2018; 83%-96%, 2020). Analysis of students' reports revealed evidence of cognitive integration of virology, population health, and bioethics concepts, including integration of new learning content.

Discussion

Collaborative problem-solving during a simulated zombie-themed pandemic provided preclinical medical students with an engaging opportunity to integrate virology, population health, and bioethics concepts. Implementing this event required advanced planning, use of multiple spaces, learning materials preparation, and recruitment of several faculty, staff, and actors.

The Simulated Virology Clinic: A Standardized Patient Exercise for Preclinical Medical Students Supporting Basic and Clinical Science Integration

INTRODUCTION

Virology is inherently challenging due to the sheer volume of information medical students are responsible for learning. Cognitive integration of this content is critical for early medical students to practice applying this knowledge to diagnostic problem-solving. Simulation offers learners engaging opportunities to practice cognitive integration. We developed a simulated clinic activity for first-year medical students consisting of standardized patient (SP) encounters representing viral infections.

METHODS

Student small groups rotated through eight SP encounters during which they collected patient histories, reviewed physical exam findings, and developed a differential diagnosis and diagnostic plan for each case. The instructor debriefed students on the cases afterward. We assessed students' evaluation of the activity through online surveys.

RESULTS

Two hundred seventy-eight students participated in the simulated clinic in 2018 and 2019. Students rated the activity as very effective for learning about the infections represented and for providing opportunities to integrate clinical skills. Students agreed that the event's instructional design was appropriate for its objectives and that the problem-solving aspect was intellectually stimulating. They indicated that the most effective aspects were solidifying illness scripts for the infections represented, integrating knowledge and skills to diagnose patients in a realistic clinical context, and working collaboratively to problem-solve.

DISCUSSION

The simulated virology clinic is an effective method for providing students opportunities to integrate microbiology and clinical skills and has been positively received by students. This instructional method offers learners an opportunity to solidify illness scripts for viral infections using an interactive, collaborative approach.

Medical Students' Clinical Reasoning During a Simulated Viral Pandemic: Evidence of Cognitive Integration and Insights on Novices' Approach to Diagnostic Reasoning

INTRODUCTION

Cognitive integration from multiple disciplines is essential to clinical problem-solving. Because it is not directly observable, demonstrating evidence of learners' cognitive integration remains a challenge. In addition, little is known about preclinical medical students' approach to diagnostic reasoning despite widespread implementation of clinical reasoning curricula for these early learners. The objectives of this study were to characterize how first-year medical students integrated knowledge to problem-solve during a simulated viral pandemic and to characterize students' diagnostic reasoning approach to this clinical scenario.

MATERIALS AND METHODS

Student teams analyzed clinical data to formulate hypotheses for the pandemic's source and submitted reports justifying their hypotheses and treatment recommendations. A content analysis on students' reports identified codes and themes characterizing the learning content integrated and students' approaches to diagnostic reasoning tasks.

RESULTS

Sixteen problem-solving codes were identified, demonstrating integration of new and previously encountered content from multiple disciplines. A compare-contrast analytical approach was the most commonly employed diagnostic reasoning approach (100%), with a smaller subset of teams also using a causal approach (20%).

DISCUSSION

Content analysis of preclinical students' diagnostic justification tasks provided insights into their approach to diagnostic reasoning, which was most consistent with the search-inference framework rather than a causal approach, likely due to limited pathophysiological knowledge at that point in training.

CONCLUSIONS

Evidence of cognitive integration can be made explicit through learners' narrative justification of diagnostic reasoning tasks. Preclinical students' diagnostic reasoning development has implications for curricular design and implementation for this learner group.

Prematriculation Healthcare Employment Predicts Success in Clerkship Environment

PURPOSE

The average age of the matriculating medical student is increasing as more students take time between college and medical school. Increasing numbers of students are employed in the healthcare field during these gap years. Studies have explored the relationship between matriculation age and medical school performance with conflicting findings. The impact of prior healthcare employment (PHE) on future clerkship performance has not been explored. We hypothesize that medical school performance metrics would be higher for students with PHE than their peers.

METHODS

A retrospective review of four medical school classes at a single institution was conducted. Each student's admission application was examined to identify students with at least 6 months paid employment in a clinical healthcare position (i.e., pre-matriculation direct patient interaction, PHE cohort). Multiple medical school performance metrics were obtained for each student.

RESULTS

Of the 434 included students, 49 were PHE (11.29%) and percent of students with PHE trended up over time. MCAT scores, USMLE Step 1, and Step 2 CK scores were not different for PHE and non-PHE medical students. PHE students had significantly higher NBME subject exams, clinical clerkship scores, and cumulative year 3 performance.

CONCLUSIONS

Students who matriculate to medical school with prior healthcare employment outperform their peers in the clinical environment, possibly due to acquisition of knowledge or skills from their prior employment. These findings support students seeking paid healthcare experiences prior to medical school and have implications for pre-medicine advising, admissions, and medical school curricula.

2707. Non 13-Valent Pneumococcal Conjugate Vaccine Serotypes Predominate as Causes of Pneumococcal Otitis Media in Children

Background

Pneumococcal acute otitis media (AOM) in children due to vaccine-related serotypes (ST) has declined after the introduction of the 13-valent pneumococcal conjugate vaccine (PCV13), although some serotypes, such has 3, 19A and 19F have persisted. Among non-vaccine serotypes, 35B has been shown to contribute substantially to both OM and invasive infections. This study describes the current epidemiology of pneumococcal OM isolates obtained from the U S Pediatric Multicenter Pneumococcal Surveillance Group (USPMPSG).

Methods

From the USPMPSG database, we collected data from patients <18 years of age with pneumococcal OM isolates from 2014 to 2018. Analysis included demographics, immunization status, antimicrobial susceptibility data and serotype. Statistical comparisons included Fisher’s exact and Wilcoxon rank-sum tests.

Results

A total of 494 patients with isolates were identified within the time period from 5 children’s hospitals. Median age was 1.7 years (range 0–17.6) and 299 (60.5%) were male; 176 (35.7%) had an underlying condition. Thirty-two patients had received no dose of either PCV7 or PCV13. Thirty-five serotypes were identified (3 isolates were non-typeable), of which 6 serotypes [35B (16.8%), 3 (9.5%), 15A (7.9%), 15B (7.9%), 23B (7.9%) and 21 (6.1%)] caused more than half of the total OM infections (figure). Ninety (18.2%) isolates were of PCV13 serotypes. Twenty-five of 476 (5.3%) isolates had a penicillin MIC>2 µg/mL. These were of serotypes 11A, 15A/C, 19A/F, 35B and NT; 10/455 (2.2%) isolates had ceftriaxone MIC>1 µg/mL and were of ST 3, 15A, 19A/F and 35B.

Conclusion

Most pneumococcal OM were caused by non-PCV13 serotypes. Serotype 35B remained the most common serotype among pneumococcal isolates recovered from ear drainage or middle ear cultures. The low proportion of penicillin-resistant isolates along with the increasing proportion of AOM cases being due to non-pneumococcal isolates supports the consideration to switch routine antibiotic treatment for AOM to standard dose amoxicillin-clavulanate from high dose amoxicillin in PCV13 immunized children (Pediatr Infect Dis J 2018;37:1255–1257).

Disclosures

All authors: No reported disclosures.

Performing Under Pressure: Varsity Athletes Excel in Medical School

PURPOSE

The admission process for medical school relies on objective and subjective measures of personal achievement, and selecting successful medical students is a daunting task for admission committees. While there is a significant body of literature examining MCAT scores and undergraduate grade point average (GPA) with medical school performance, there is a paucity of research on impact of specific student accomplishments on future performance. We hypothesize participation in a varsity collegiate sport will correlate with higher performance during medical school.

METHODS

A retrospective review of four medical school classes at a single institution was completed. Each student's admission application was examined for at least 1 year of participation in a varsity-level sport at their respective undergraduate institution. A total of 62 athletes (16.36%) were identified out of 441 total students. Multiple medical school performance metrics were obtained for each student.

RESULTS

There was no difference in MCAT scores between athletes and non-athlete medical students. There was a significant difference in step 1, step 2 CK, NBME shelf exams, cumulative year 3 performance, and AOA status with the athletes outperforming their peers.

CONCLUSION

Students who participate in collegiate varsity athletics excel in medical school. One explanation for this finding may be participation in high-stakes athletic training and competition results in development of specific attributes beneficial in medical school. These attributes may include receptiveness to criticism, time management, resiliency, team participation, and performing under pressure. Additional research is needed to elucidate the attributes that determine improved medical school performance, such that medical educators can utilize this knowledge to better prepare all students for the rigors of medical school.

Association of Prior Vaccination With Influenza Vaccine Effectiveness in Children Receiving Live Attenuated or Inactivated Vaccine

IMPORTANCE

Some studies have reported negative effects of prior-season influenza vaccination. Prior-season influenza vaccination effects on vaccine effectiveness (VE) in children are not well understood.

OBJECTIVE

To assess the association of prior-season influenza vaccination with subsequent VE in children aged 2 to 17 years.

DESIGN, SETTING, AND PARTICIPANTS

This multiseason, test-negative case-control study was conducted in outpatient clinics at 4 US sites among children aged 2 to 17 years with a medically attended febrile acute respiratory illness. Participants were recruited during the 2013-2014, 2014-2015, and 2015-2016 seasons when influenza circulated locally. Cases were children with influenza confirmed by reverse-transcription polymerase chain reaction. Test-negative control individuals were children with negative test results for influenza.

EXPOSURES

Vaccination history, including influenza vaccine type received in the enrollment season (live attenuated influenza vaccine [LAIV], inactivated influenza vaccine [IIV], or no vaccine) and season before enrollment (LAIV, IIV, or no vaccine), determined from medical records and immunization registries.

MAIN OUTCOMES AND MEASURES

LAIV and IIV effectiveness by influenza type and subtype (influenza A[H1N1]pdm09, influenza A[H3N2], or influenza B), estimated as 100 × (1 - odds ratio) in a logistic regression model with adjustment for potential confounders. Prior season vaccination associations were assessed with an interaction term.

RESULTS

Of 3369 children (1749 [52%] male; median age, 6.6 years [range, 2-17 years]) included in the analysis, 772 (23%) had a positive test result for influenza and 1674 (50%) were vaccinated in the enrollment season. Among LAIV recipients, VE against influenza A(H3N2) was higher among children vaccinated in both the enrollment and 1 prior season (50.3% [95% CI, 17.0% to 70.2%]) than among those without 1 prior season vaccination (-82.4% [95% CI, -267.5% to 9.5%], interaction P < .001). The effectiveness of LAIV against influenza A(H1N1)pdm09 was not associated with prior season vaccination among those with prior season vaccination (47.5% [95% CI, 11.4% to 68.9%]) and among those without prior season vaccination (7.8% [95% CI, -101.9% to 57.9%]) (interaction P = .37). Prior season vaccination was not associated with effectiveness of IIV against influenza A(H3N2) (38.7% [95% CI, 6.8% to 59.6%] among those with prior-season vaccination and 23.2% [95% CI, -38.3% to 57.4%] among those without prior-season vaccination, interaction P = .16) or with effectiveness of IIV against influenza A[H1N1]pdm09 (72.4% [95% CI, 56.0% to 82.7%] among those with prior season vaccination and 67.5% [95% CI, 32.1% to 84.4%] among those without prior season vaccination, interaction P = .93). Residual protection from prior season vaccination only (no vaccination in the enrollment season) was observed for influenza B (LAIV: 60.0% [95% CI, 36.8% to 74.7%]; IIV: 60.0% [36.9% to 74.6%]). Similar results were observed in analyses that included repeated vaccination in 2 and 3 prior seasons.

CONCLUSIONS AND RELEVANCE

Influenza VE varied by influenza type and subtype and vaccine type, but prior-season vaccination was not associated with reduced VE. These findings support current recommendations for annual influenza vaccination of children.

2015-2016 Vaccine Effectiveness of Live Attenuated and Inactivated Influenza Vaccines in Children in the United States

Background

In the 2015-2016 season, quadrivalent live attenuated influenza vaccine (LAIV) and both trivalent and quadrivalent inactivated influenza vaccine (IIV) were available in the United States.

Methods

This study, conducted according to a test-negative case-control design, enrolled children aged 2-17 years presenting to outpatient settings with fever and respiratory symptoms for <5 days at 8 sites across the United States between 30 November 2015 and 15 April 2016. A nasal swab was obtained for reverse-transcriptase polymerase chain reaction (RT-PCR) testing for influenza, and influenza vaccination was verified in the medical record or vaccine registry. Influenza vaccine effectiveness (VE) was estimated using a logistic regression model.

Results

Of 1012 children retained for analysis, most children (59%) were unvaccinated, 10% received LAIV, and 31% received IIV. Influenza A (predominantly antigenically similar to the A/California/7/2009 strain) was detected in 14% and influenza B (predominantly a B/Victoria lineage) in 10%. For all influenza, VE was 46% (95% confidence interval [CI], 7%-69%) for LAIV and 65% (48%-76%) for IIV. VE against influenza A(H1N1)pdm09 was 50% (95% CI, -2% to 75%) for LAIV and 71% (51%-82%) for IIV. The odds ratio for vaccine failure with RT-PCR-confirmed A(H1N1)pdm09 was 1.71 (95% CI, 0.78-3.73) in LAIV versus IIV recipients.

Conclusions

LAIV and IIV demonstrated effectiveness against any influenza among children aged 2-17 years in 2015-2016. When compared to all unvaccinated children, VE against influenza A(H1N1)pdm09 was significant for IIV but not LAIV.

Clinical Trials Registration

NCT01997450.

Impact of Prior Vaccination History on Risk of Vaccine Failure with Live Attenuated and Inactivated Influenza Vaccines in Children, 2013–14 through 2015–16

Background

Prior season vaccination may influence influenza vaccine effectiveness; however, little is known about the impact of prior vaccination or vaccine type received. We assessed prior vaccination history and risk of influenza in children over 3 seasons.

Methods

Children aged 2–17 years seeking outpatient care for febrile acute respiratory illness were recruited during the 2013–14 through 2015–16 seasons (1 vaccine-mismatched H3N2 season and 2 H1N1pdm09 seasons) at 4 US sites. Influenza was confirmed by RT-PCR. Vaccination data for the season of enrollment (current) and 3 prior seasons were obtained from medical records and immunization registries. Among children who received 1 dose of influenza vaccine during the current season, risk of vaccine failure (ie, PCR-confirmed influenza) was estimated using test-negative design with logistic regression models adjusted for age, season, enrollment site, enrollment week (relative to peak), and outpatient visits. Risk of failure with live attenuated influenza vaccine (LAIV) and inactivated influenza vaccine (IIV) were modeled separately. Separate models were used for vaccine history based on number of seasons and vaccine type received (ie, none, LAIV, IIV, both).

Results

Influenza was detected in 191 (12%) of 1601 children who received 1 vaccine dose during the current season: 117 H3N2 and 74 H1N1pdm09. Among 508 current season LAIV recipients, 239 (47%) received LAIV and 144 (28%) received IIV in the prior season. Among 1093 current season IIV recipients, 94 (9%) received LAIV and 711 (65%) received IIV in the prior season. For LAIV, receipt of vaccine (any type) in a prior season was associated with a decreased risk of H3N2 failure (odds ratio 0.23; 95% CI, 0.09–0.57). Prior vaccination was not associated with risk of LAIV vaccine failure against H1N1pdm09. For IIV, there was no evidence that prior vaccination was associated with risk of vaccine failure against H3N2 or H1N1pdm09. Similar results were seen in children without any high-risk conditions.

Conclusion

Risk of vaccine failure among vaccinated children varied by vaccine type and virus subtype. Future studies should examine immunologic effects to better understand these differences.

Disclosures

H. Q. McLean, MedImmune: Grant Investigator, Research support; H. Caspard, MedImmune: Employee, Salary; M. R. Griffin, MedImmune: Grant Investigator, Grant recipient; M. Gaglani, MedImmune: Investigator, Research support; T. R. Peters, MedImmune: Investigator, Research support; K. A. Poehling, MedImmune: Investigator, Research support; C. S. Ambrose, AstraZeneca: Employee, Salary; E. Belongia, MedImmune: Grant Investigator, Research support

Effectiveness of live attenuated influenza vaccine and inactivated influenza vaccine in children during the 2014-2015 season

BACKGROUND

A clinical study found that live attenuated influenza vaccine (LAIV) was superior to inactivated influenza vaccine (IIV) against drifted A(H3N2) viruses in children. During the 2014-2015 influenza season, widespread circulation of antigenically and genetically drifted A(H3N2) viruses provided an opportunity to evaluate subtype-specific vaccine effectiveness (VE) of quadrivalent LAIV (LAIV4) and IIV in children.

METHODS

Children (2-17years) with febrile acute respiratory illness <5days' duration were enrolled at 4 outpatient sites in the United States during the 2014-2015 influenza season. Nasal swabs were tested for influenza by reverse transcription polymerase chain reaction; vaccination dates were obtained from medical records or immunization registries. VE was estimated using a test-negative design comparing odds of vaccination among influenza cases and test-negative controls with adjustment for potential confounders.

RESULTS

Among 1696 children enrolled, 1511 (89%) were included in the analysis. Influenza was detected in 427 (28%) children; 317 had influenza A(H3N2) and 110 had influenza B. Most influenza isolates were characterized as a drifted strain of influenza A(H3N2) or a drifted strain of B/Yamagata. For LAIV4, adjusted VE was 50% (95% confidence interval [CI], 27-66%) against any influenza, 30% (95% CI, -6% to 54%) against influenza A(H3N2), and 87% (95% CI, 63-96%) against type B. For IIV, adjusted VE was 39% (95% CI, 18-54%) against any influenza, 40% (95% CI, 16-58%) against A(H3N2), and 29% (95% CI, -15% to 56%) against type B. Odds of influenza for LAIV4 versus IIV recipients were similar against influenza A(H3N2) (odds ratio [OR], 1.17; 95% CI, 0.73-1.86) and lower against influenza B (OR, 0.18; 95% CI, 0.06-0.55).

CONCLUSIONS

LAIV4 and IIV provided similar protection against a new antigenic variant A(H3N2). LAIV4 provided significantly greater protection than IIV against a drifted influenza B strain. ClinicalTrials.gov identifier: NCT01997450.

Estimating the Burden of Pandemic Infectious Disease: The Case of the Second Wave of Pandemic Influenza H1N1 in Forsyth County, North Carolina

BACKGROUND

Understanding the burden of influenza A(H1N1)pdm09 virus during the second wave of 2009-2010 is important for future pandemic planning.

METHODS

Persons who presented to the emergency department (ED) or were hospitalized with fever and/or acute respiratory symptoms at the academic medical center in Forsyth County, North Carolina were prospectively enrolled and underwent nasal/throat swab testing for influenza A(H1N1)pdm09. Laboratory-confirmed cases of influenza A(H1N1)pdm09 virus identified through active surveillance were compared by capture-recapture analysis to those identified through independent, passive surveillance (physician-ordered influenza testing). This approach estimated the number of total cases, including those not captured by either surveillance method. A second analysis estimated the total number of influenza A(H1N1)pdm09 cases by multiplying weekly influenza percentages determined via active surveillance by weekly counts of influenza-associated discharge diagnoses from administrative data. Market share adjustments were used to estimate influenza A(H1N1)pdm09 virus ED visits or hospitalizations per 1,000 residents.

RESULTS

Capture-recapture analysis estimated that 753 residents (95% confidence interval [CI], 424-2,735) with influenza A(H1N1)pdm09 virus were seen in the academic medical center from September 2009 through mid-April 2010; this result yielded an estimated 4.7 (95% CI, 2.6-16.9) influenza A(H1N1)pdm09 virus ED visits or hospitalizations per 1,000 residents. Similarly, 708 visits were estimated using weekly influenza percentages and influenza-associated discharge diagnoses, yielding an estimated 4.4 influenza A(H1N1)pdm09 virus ED visits or hospitalizations per 1,000 residents.

CONCLUSION

This study demonstrates that the burden of influenza A(H1N1)pdm09 virus in ED and inpatient settings by capture-recapture analysis was 4-5 per 1,000 residents; this rate was approximately 8-fold higher than that detected by physician-ordered influenza testing.

Effectiveness of live attenuated influenza vaccine and inactivated influenza vaccine in children 2-17 years of age in 2013-2014 in the United States

BACKGROUND

A postmarketing observational study was initiated to evaluate quadrivalent live attenuated influenza vaccine (LAIV) effectiveness in children aged 2-17 years in the United States.

METHODS

Children and adolescents aged 2-17 years seeking outpatient care for febrile acute respiratory illness <5 days duration were enrolled at 4 geographically diverse sites during the 2013-2014 influenza season. Nasal swabs were tested for influenza using reverse transcription polymerase chain reaction. Vaccination status was documented from medical records or immunization registries. Children who received ≥1 dose of influenza vaccine ≥14 days before study visit were considered vaccinated. Vaccine effectiveness (VE) was estimated as 100×(1-adjusted odds ratio), where the odds of interest are the odds of vaccine exposure among influenza cases and test-negative controls.

RESULTS

In total, 1033 children and adolescents were included in the analysis. Influenza was detected in 14% (145/1033) of all children, with 74% (108/145) of the influenza cases due to A/H1N1pdm09 strains, 21% (31) to influenza B, and 4% (6) to influenza H3N2. LAIV did not show significant effectiveness against A/H1N1pdm09 (VE 13% [95% CI: -55 to 51]) but was effective against B/Yamagata strains (82% [95% CI: 12-96]). Inactivated influenza vaccine was effective against A/H1N1pdm09 (74% [95% CI: 50-86]) and B/Yamagata (70% [95% CI: 18-89]).

CONCLUSIONS

LAIV provided significant protection against B/Yamagata influenza but not against A/H1N1pdm09 in children aged 2-17 years in 2013-2014, resulting in a proposed change of the 2015-2016 formulation with a new and more heat-stable A/H1N1pdm09 LAIV strain.

Predictors of Influenza Diagnosis Among Patients With Laboratory-Confirmed Influenza

OBJECTIVE

This study was performed to determine predictors of clinical influenza diagnosis among patients with laboratory-confirmed influenza.

METHODS

Prospective, laboratory-confirmed surveillance for influenza was conducted among patients of all ages who were hospitalized or presented to the emergency department with fever and respiratory symptoms during 2009-2013. We evaluated all enrolled persons who had influenza confirmed by viral culture and/or polymerase chain reaction and received any discharge diagnosis. The primary outcome, clinical influenza diagnosis, was defined as (1) a discharge diagnosis of influenza, (2) a prescription of neuraminidase inhibitor, or (3) a rapid test positive for influenza virus. Bivariate analyses and multiple logistic regression modeling were performed.

RESULTS

Influenza was diagnosed for 29% of 504 enrolled patients with laboratory-confirmed influenza and for 56% of 236 patients with high-risk conditions. Overall, clinical influenza diagnosis was predicted by race/ethnicity, insurance status, year, being hospitalized, having high-risk conditions, and receiving no diagnosis of bacterial infection. Being diagnosed with a bacterial infection reduced the odds of receiving an influenza diagnosis by >3-fold for all patients and for patients with high-risk conditions.

CONCLUSIONS

Many influenza virus-positive patients, including those with high-risk conditions, do not receive a clinical diagnosis of influenza. The pattern of clinical diagnoses among influenza virus-positive patients suggests preferential consideration of bacterial diseases as a diagnosis.

Multicenter surveillance of Streptococcus pneumoniae isolates from middle ear and mastoid cultures in the 13-valent pneumococcal conjugate vaccine era

BACKGROUND

Streptococcus pneumoniae is a common cause of otitis media (OM) in children; mastoiditis remains an important complication of OM. Limited data are available on the impact of the 13-valent pneumococcal conjugate vaccine (PCV13) on pneumococcal otitis.

METHODS

Investigators from 8 children's hospitals in the United States prospectively collected pneumococcal isolates from middle ear or mastoid cultures from children from 2011 to 2013. Serotype and antibiotic susceptibilities were determined and PCV13 doses for children documented.

RESULTS

Over the 3-year period, the proportion of isolates included in PCV13 (plus a related serotype) decreased significantly (P = .0006) among the middle ear/mastoid isolates (2011, 50% [74/149]; 2012, 40.5% [47/116]; 2013, 29% [34/118]). The number of serotype 19A isolates in 2013 (n = 12, 10.2% of total) decreased 76% compared with the number of 19A isolates in 2011 (n = 50, 33.6% of total). Of the children from whom serotype 19A was isolated (n = 93), 55% had previously received <3 doses of PCV13. The most common non-PCV13 serotypes for the combined years were 35B (n = 37), 21 (n = 20), 23B (n = 20), 15B (n = 18), 11 (n = 17), 23A (n = 14), 15A (n = 14), and 15C (n = 14). The proportion of isolates with a penicillin minimal inhibitory concentration >2 µg/mL decreased significantly over the 3 years (2011, 22% [35/154]; 2012, 20% [24/118]; 2013, 10% [12/120]; P < .02).

CONCLUSIONS

The number of pneumococcal isolates and the percentage of isolates with high-level penicillin resistance from cultures taken from children with OM or mastoiditis for clinical indications have decreased following PCV13 use, largely related to decreases in serotype 19A isolates.

Relative timing of influenza disease by age group

A detailed understanding of influenza movement in communities during yearly epidemics is needed to inform improved influenza control programs. We sought to determine the relative timing of influenza presentation and symptom onset by age group and influenza strain. Prospective, laboratory-confirmed surveillance was performed over three moderate influenza seasons in emergency departments and inpatient settings of both medical centers in Winston-Salem, NC. Influenza disease presented first in school age children through community epidemics of influenza A(H1N1)pdm09 and influenza B, and first in persons 5-49 years old for influenza A(H3N2). This finding indicates that influenza prevention in persons 5-49 years of age may be particularly important in influenza epidemic control.

Influenza testing, diagnosis, and treatment in the emergency department in 2009-2010 and 2010-2011

OBJECTIVES

The objective was to describe patterns of rapid influenza test ordering, diagnosis of influenza, and antiviral prescribing by the treating physician for children and adults presenting to emergency departments (EDs) with fever and acute respiratory symptoms in Winston-Salem, North Carolina, over two influenza seasons.

METHODS

The authors prospectively enrolled patients presenting to the ED with fever and acute respiratory symptoms for two influenza seasons: H1N1 pandemic of September 2009 through mid-May 2010 and November 2010 through April 2011. Enrolled patients had nose or and throat swabs obtained and tested for influenza by viral culture and polymerase chain reaction (PCR) testing. Demographic information and medical history were obtained by patient or guardian report. Testing, treatment, and discharge diagnosis from the ED visit, as well as medical history and insurance status, were ascertained from chart review.

RESULTS

Among 2,293 eligible patients approached, 1,657 (72%) were enrolled, of whom 38% were younger than 18 years, 47% were 18 to 49 years, and 15% were 50 years of age and older. Overall, 14% had culture- or PCR-confirmed influenza. The odds of 1) rapid influenza test ordering, 2) a physician diagnosis of influenza, and 3) prescribing antiviral treatment during the ED visit were fourfold higher among patients with than without culture- or PCR-confirmed influenza. The odds of rapid influenza test ordering were threefold lower in 2009/2010 than 2010/2011, whereas the odds of physician diagnosis of influenza and antiviral prescriptions were 2- and 3.5-fold higher, respectively.

CONCLUSIONS

In 2009/2010 compared to 2010/2011, the odds of rapid influenza test ordering were lower, whereas the odds of influenza-specific discharge diagnoses and antiviral prescriptions were higher among patients presenting to the ED with culture/PCR-confirmed influenza. These results demonstrated a gap between clinical practice and recommendations for the diagnosis and treatment of influenza from the Centers for Disease Control and Prevention (CDC).

Verifying influenza and pneumococcal immunization status of children in 2009-2010 from primary care practice records and from the North Carolina Immunization Registry

BACKGROUND

The North Carolina Immunization Registry (NCIR) has been available since 2004. We sought to measure its utilization among practices that provide primary care for children who are enrolled in a prospective influenza surveillance study.

METHODS

This study included children aged 0.5-17 years who presented with fever or acute respiratory symptoms to an emergency department or inpatient setting in Winston-Salem, North Carolina, from September 1, 2009, through May 19, 2010. Study team members verified influenza and pneumococcal immunization status by requesting records from each child's primary care practice and by independently reviewing the NCIR. We assessed agreement of nonregistry immunization medical records with NCIR data using the kappa statistic.

RESULTS

Fifty-six practices confirmed the immunization status of 292 study-enrolled children. For most children (238/292, 82%), practices verified the child's immunizations by providing a copy of the NCIR record. For 54 children whose practices verified their immunizations by providing practice records alone, agreement with the NCIR by the kappa statistic was 0.6-0.7 for seasonal and monovalent H1N1 influenza vaccines and 0.8-0.9 for pneumococcal conjugate and polysaccharide vaccines. A total of 221 (98%) of 226 enrolled children younger than 6 years of age had 2 or more immunizations documented in the NCIR.

LIMITATIONS

NCIR usage may vary in other regions of North Carolina.

CONCLUSION

More than 95% of children younger than 6 years of age had 2 or more immunizations documented in the NCIR; thus, the Centers for Disease Control and Prevention 2010 goal for immunization information systems was met in this population. We found substantial agreement between practice records and the NCIR for influenza and pneumococcal immunizations in children.

Exposure to influenza virus aerosols during routine patient care

BACKGROUND

Defining dispersal of influenza virus via aerosol is essential for the development of prevention measures.

METHODS

During the 2010-2011 influenza season, subjects with influenza-like illness were enrolled in an emergency department and throughout a tertiary care hospital, nasopharyngeal swab specimens were obtained, and symptom severity, treatment, and medical history were recorded. Quantitative impaction air samples were taken not ≤0.305 m (1 foot), 0.914 m (3 feet), and 1.829 m (6 feet) from the patient's head during routine care. Influenza virus was detected by rapid test and polymerase chain reaction.

RESULTS

Sixty-one of 94 subjects (65%) tested positive for influenza virus. Twenty-six patients (43%) released influenza virus into room air, with 5 (19%) emitting up to 32 times more virus than others. Emitters surpassed the airborne 50% human infectious dose of influenza virus at all sample locations. Healthcare professionals (HCPs) were exposed to mainly small influenza virus particles (diameter, <4.7 µm), with concentrations decreasing with increasing distance from the patient's head (P < .05). Influenza virus release was associated with high viral loads in nasopharyngeal samples (shedding), coughing, and sneezing (P < .05). Patients who reported severe illness and major interference with daily life also emitted more influenza virus (P < .05).

CONCLUSIONS

HCPs within 1.829 m of patients with influenza could be exposed to infectious doses of influenza virus, primarily in small-particle aerosols. This finding questions the current paradigm of localized droplet transmission during non-aerosol-generating procedures.

Potential impact of parental Tdap immunization on infant pertussis hospitalizations

We estimated the potential impact of parental Tdap immunization before delivery, at delivery and at the 2-week newborn visit on U.S. infant pertussis hospitalizations. We used published data for pertussis hospitalization rates among U.S. infants aged 0-4 months, the Tdap vaccine efficacy in adults, and the proportion of infants with pertussis <6 months of age in which either parent was the source (16-40% from mothers and 16-20% from fathers). Immunizing parents before pregnancy or ≥ 2 weeks prior to delivery should reduce pertussis hospitalizations among infants 0-4 months by 2694-9314 if both parents are vaccinated, and by 1347-6909 if only mothers are vaccinated. Greater reductions in pertussis hospitalizations would be achieved if parents are immunized ≥ 2 weeks prior to delivery than after delivery or the 2-week newborn visit. Although immunizing parents prior to pregnancy or delivery is best, immunizing parents in the postpartum period should provide protection to that newborn and to infants of subsequent pregnancies.

Potential impact of accelerating the primary dose of rotavirus vaccine in infants

We estimated the potential impact of administering the first dose of rotavirus vaccine at 6 weeks (42 days of life) instead of 2 months of age, which is permissible for all U.S. vaccines recommended at 2 months of age, on rotavirus hospitalization rates. We used published data for hospitalization rates, vaccine coverage, and vaccine efficacy after one dose and assumed a two-week delay in seroconversion after vaccine administration in the United States. Administering the first dose of rotavirus vaccine at 6 weeks instead of 8 weeks of age should have prevented 1110, 1660, and 2210 rotavirus hospitalizations among U.S. infants <3 months of age in 2006 when the vaccine was first introduced. This estimated benefit represents a 2-4% reduction in rotavirus hospitalizations among children <5 years of age.

Detection of group A Streptococcus in tonsils from pediatric patients reveals high rate of asymptomatic streptococcal carriage

Background

Group A Streptococcus (GAS) causes acute tonsillopharyngitis in children, and approximately 20% of this population are chronic carriers of GAS. Antibacterial therapy has previously been shown to be insufficient at clearing GAS carriage. Bacterial biofilms are a surface-attached bacterial community that is encased in a matrix of extracellular polymeric substances. Biofilms have been shown to provide a protective niche against the immune response and antibiotic treatments, and are often associated with recurrent or chronic bacterial infections. The objective of this study was to test the hypothesis that GAS is present within tonsil tissue at the time of tonsillectomy.

Methods

Blinded immunofluorescent and histological methods were employed to evaluate palatine tonsils from children undergoing routine tonsillectomy for adenotonsillar hypertrophy or recurrent GAS tonsillopharyngitis.

Results

Immunofluorescence analysis using anti-GAS antibody was positive in 11/30 (37%) children who had tonsillectomy for adenotonsillar hypertrophy and in 10/30 (33%) children who had tonsillectomy for recurrent GAS pharyngitis. Fluorescent microscopy with anti-GAS and anti-cytokeratin 8 & 18 antibodies revealed GAS was localized to the tonsillar reticulated crypts. Scanning electron microscopy identified 3-dimensional communities of cocci similar in size and morphology to GAS. The characteristics of these communities are similar to GAS biofilms from in vivo animal models.

Conclusion

Our study revealed the presence of GAS within the tonsillar reticulated crypts of approximately one-third of children who underwent tonsillectomy for either adenotonsillar hypertrophy or recurrent GAS tonsillopharyngitis at the Wake Forest School of Medicine.

Trial Registration

The tissue collected was normally discarded tissue and no patient identifiers were collected. Thus, no subjects were formally enrolled.

2009-2010 seasonal influenza vaccination coverage among college students from 8 universities in North Carolina

OBJECTIVE

The authors sought to describe the 2009-2010 seasonal influenza vaccine coverage of college students.

PARTICIPANTS

A total of 4,090 college students from 8 North Carolina universities participated in a confidential, Web-based survey in October-November 2009.

METHODS

Associations between self-reported 2009-2010 seasonal influenza vaccination and demographic characteristics, campus activities, parental education, and e-mail usage were assessed by bivariate analyses and by a mixed-effects model adjusting for clustering by university.

RESULTS

Overall, 20% of students (range 14%-30% by university) reported receiving 2009-2010 seasonal influenza vaccine. Being a freshman, attending a private university, having a college-educated parent, and participating in academic clubs/honor societies predicted receipt of influenza vaccine in the mixed-effects model.

CONCLUSIONS

The self-reported 2009-2010 influenza vaccine coverage was one-quarter of the 2020 Healthy People goal (80%) for healthy persons 18 to 64 years of age. College campuses have the opportunity to enhance influenza vaccine coverage among its diverse student populations.

Assessment of parental report for 2009-2010 seasonal and monovalent H1N1 influenza vaccines among children in the emergency department or hospital

OBJECTIVE

To assess the validity of parental report for seasonal and monovalent H1N1 influenza vaccinations among children 6 months to <18 years who were recommended to receive both vaccines in 2009-2010.

METHODS

Children with fever or respiratory symptoms were prospectively enrolled in both emergency departments in Forsyth County, North Carolina, and the only pediatric hospital in the region. Enrollment occurred from September 1, 2009, through April 12, 2010, during the H1N1 influenza pandemic. A parental questionnaire was administered by trained interviewers to ascertain the status of seasonal and monovalent H1N1 influenza vaccines. Parental report was compared with that documented in the medical record and/or the North Carolina immunization registry.

RESULTS

Among 297 enrolled children 6 months to <18 years of age, 174 (59%) were 6 months to 4 years, 67 (23%) were 5-8 years, and 56 (19%) were 9 to <18 years. Parents reported that 140 (47%) children had received ≥1 dose of 2009-2010 influenza vaccine-128 (43%) for seasonal vaccine and 63 (21%) for H1N1 vaccine. Confirmed vaccination data indicated that 156 (53%) children had received ≥1 dose of any 2009-2010 vaccine-120 (40%) for seasonal vaccine and 53 (18%) for H1N1 vaccine. Parental report of any seasonal influenza vaccination was 92% sensitive and 86% specific and had a kappa of 0.76. Parental report for any H1N1 influenza vaccination was 88% sensitive and 92% specific with a kappa of 0.71.

CONCLUSIONS

Parental report of 2009-2010 seasonal and monovalent H1N1 influenza vaccinations was sensitive and specific and had reasonable agreement with the medical record and/or immunization registry.

Transocular entry of seasonal influenza-attenuated virus aerosols and the efficacy of n95 respirators, surgical masks, and eye protection in humans

BACKGROUND

The efficacy of barrier precautions to prevent influenza transmission is unknown.

METHODS

Twenty-eight participants were exposed to monodispersed live attenuated influenza vaccine (LAIV) particles (4.9 μm) in 6 groups: group 1, no precautions; group 2, ocular exposure only; group 3, surgical mask without eye protection; group 4, surgical mask with eye protection; group 5, fit-tested N95 respirator without eye protection; and group 6, fit-tested N95 respirator with eye protection. Influenza was detected by reverse-transcription polymerase chain reaction (RT-PCR) and culture in nasal washes. Exact 95% confidence intervals (CIs) were calculated.

RESULTS

Influenza was detected in 4 of 4 participants in group 1 (95% CI, 0-.60), 3 of 4 in group 2 (95% CI, .006-.806]), 5 of 5 in group 3 (95% CI, 0-.522), 5 of 5 in group 4, (95% CI, 0-.522), 3 of 5 in group 5 (95% CI, .053-.853), and 1 of 5 in group 6 (95% CI, .05-.72). RT-PCR revealed significant differences between group 1 and all other groups except group 3.

CONCLUSIONS

Transocular transmission of LAIV occured in most participants suggesting the necessity of eye protection. An N95 respirator provided the best guard further enhanced by eye protection.

Potential impact of accelerating the primary dose of pneumococcal conjugate vaccine in infants

OBJECTIVE

To estimate the potential effect of the acceleration of administration of the first dose of pneumococcal conjugate vaccine from 2 months to 6 weeks of age.

DESIGN

Prediction model using data from a retrospective cohort study.

SETTING

Published data from 8 states that participated in Active Bacterial Core Surveillance of the Emerging Infections Program Network for pneumococcus before pneumococcal conjugate vaccine introduction (July 1, 1997- June 30, 2000).

PARTICIPANTS

A total of 759 739 live births under surveillance. Intervention Estimating the potential benefit of administration of the first dose of the pneumococcal conjugate vaccine at 6 weeks of age instead of 2 months of age.

MAIN OUTCOME MEASURES

Estimation of reduction in the rate of invasive pneumococcal disease in infants 61 to 90 days of age.

RESULTS

The estimated direct effect of the acceleration of administration of the first dose of pneumococcal conjugate vaccine from 2 months to 6 weeks of age when this vaccine was first introduced could have reduced the burden of invasive pneumococcal disease in infants 61 to 90 days of age by 39.9%, 56.0%, and 72.1% for respective vaccine efficacies of 50%, 70%, and 90%. This translates into preventing an estimated 73, 103, and 133 cases of invasive pneumococcal disease per year among approximately 4 112 052 live births in the United States.

CONCLUSIONS

The acceleration of administration of the pneumococcal conjugate vaccine from 2 months to 6 weeks of age could reduce the burden of invasive pneumococcal disease among infants. This observation may be important when a new conjugate vaccine becomes available, particularly among populations with prevalent invasive pneumococcal disease from a serotype included in the new vaccine.

Human metapneumovirus nucleoprotein and phosphoprotein interact and provide the minimal requirements for inclusion body formation

Human metapneumovirus (HMPV) is a recently discovered paramyxovirus of the subfamily Pneumovirinae, which also includes avian pneumovirus and human respiratory syncytial virus (HRSV). HMPV is an important cause of respiratory disease worldwide. To understand early events in HMPV replication, cDNAs encoding the HMPV nucleoprotein (N), phosphoprotein (P), matrix protein (M), M2-1 protein and M2-2 protein were cloned from cells infected with the genotype A1 HMPV wild-type strain TN/96-12. HMPV N and P were shown to interact using a variety of techniques: yeast two-hybrid assays, co-immunoprecipitation and fluorescence resonance energy transfer (FRET). Confocal microscopy studies showed that, when expressed individually, fluorescently tagged HMPV N and P exhibited a diffuse expression pattern in the host-cell cytoplasm of uninfected cells but were recruited to cytoplasmic viral inclusion bodies in HMPV-infected cells. Furthermore, when HMPV N and P were expressed together, they also formed cytoplasmic inclusion-like complexes, even in the absence of viral infection. FRET microscopy revealed that HMPV N and P interacted directly within cytoplasmic inclusion-like complexes. Moreover, it was shown by yeast two-hybrid analysis that the N-terminal 28 aa are required for the recruitment to and formation of cytoplasmic inclusions, but are dispensable for binding to HMPV P. This work showed that HMPV N and P proteins provide the minimal viral requirements for HMPV inclusion body formation, which may be a distinguishing characteristic of members of the subfamily Pneumovirinae.

Potential impact of acceleration of the pertussis vaccine primary series for infants

OBJECTIVE

This study estimates the potential impact, on rates of pertussis infections, hospitalizations, and deaths among infants in the United States, of administering the first dose of diphtheria and tetanus toxoids and acellular pertussis vaccine at 6 weeks rather than 2 months of age.

METHODS

We used existing data to estimate current US rates of pertussis infections, hospitalizations, and deaths according to age and infant population in 2004. We then estimated the potential impact of accelerating the administration of the first dose of diphtheria and tetanus toxoids and acellular pertussis vaccine from 2 months to 6 weeks of age, an alternative schedule consistent with current vaccination guidelines. We used Poisson distribution analysis to determine 95% confidence intervals for projected rates of pertussis disease.

RESULTS

Acceleration of administration of the first dose of diphtheria and tetanus toxoids and acellular pertussis vaccine from 2 months to 6 weeks of age is expected to prevent 1236 cases of pertussis, 898 hospitalizations, and 7 deaths attributable to pertussis per year in the United States. These decreases represent 9% reduction in cases, 9% reduction in hospitalizations, and 6% reduction in deaths attributable to pertussis among infants <3 months of age. Acceleration of the second and third doses by 2 weeks is expected to prevent an additional 923 cases, 520 hospitalizations, and 2 deaths attributable to pertussis each year.

CONCLUSION

Acceleration of administration of diphtheria and tetanus toxoids and acellular pertussis vaccine from 2 months to 6 weeks should reduce the burden of pertussis among young infants.

Bartonella henselae endocarditis in a child

14-year-old white male with a past medical history of congenital bicuspid aortic valve, Streptococcus viridans endocarditis, and pulmonary valve homograft presented with culture-negative endocarditis. Molecular studies identified the causative organism as Bartonella henselae and subsequent serologic studies supported this diagnosis. This rare cause of endocarditis may be under recognized in children. Bartonella henselae endocarditis should be considered in all children with culture-negative endocarditis, and molecular studies using a polymerase chain reaction-based assay should be routinely utilized in the evaluation of all endocarditis cases that are culture negative to rapidly diagnosis this treatable cause of endocarditis.

AP-3 directs the intracellular trafficking of HIV-1 Gag and plays a key role in particle assembly

Gag proteins direct the process of retroviral particle assembly and form the major protein constituents of the viral core. The matrix region of the HIV-1 Gag polyprotein plays a critical role in the transport of Gag to the plasma membrane assembly site. Recent evidence indicates that Gag trafficking to late endosomal compartments, including multivesicular bodies, occurs prior to viral particle budding from the plasma membrane. Here we demonstrate that the matrix region of HIV-1 Gag interacts directly with the delta subunit of the AP-3 complex, and that this interaction plays an important functional role in particle assembly. Disruption of this interaction eliminated Gag trafficking to multivesicular bodies and diminished HIV particle formation. These studies illuminate an early step in retroviral particle assembly and provide evidence that the trafficking of Gag to late endosomes is part of a productive particle assembly pathway.

Intracellular localization and protein interactions of the gene 1 protein p28 during mouse hepatitis virus replication

Coronaviruses encode the largest replicase polyprotein of any known positive-strand RNA virus. Replicase protein precursors and mature products are thought to mediate the formation and function of viral replication complexes on the surfaces of intracellular double-membrane vesicles. However, the functions of only a few of these proteins are known. For the coronavirus mouse hepatitis virus (MHV), the first proteolytic processing event of the replicase polyprotein liberates an amino-terminal 28-kDa product (p28). While previous biochemical studies have suggested that p28 is associated with viral replication complexes, the intracellular localization and interactions of p28 with other proteins during the course of MHV replication have not been defined. We used immunofluorescence confocal microscopy to show that p28 localizes to viral replication complexes in the cytoplasm during early times postinfection. However, at late times postinfection, p28 localizes to sites of M accumulation distinct from the replication complex. Furthermore, by yeast two-hybrid and coimmunoprecipitation analyses, we demonstrate that p28 specifically binds to p10 and p15, two coronavirus replicase proteins of unknown function. Deletion mutagenesis experiments determined that the carboxy terminus of p28 is not required for its interactions with p10 and p15. These results suggest that p28 may play a part at the replication complex by interacting with p10 and p15. Moreover, our findings highlight a potential role for p28 at virion assembly sites.

Reovirus sigma NS and mu NS proteins form cytoplasmic inclusion structures in the absence of viral infection

Reovirus replication occurs in the cytoplasm of infected cells and culminates in the formation of crystalline arrays of progeny virions within viral inclusions. Two viral nonstructural proteins, sigma NS and micro NS, and structural protein sigma 3 form protein-RNA complexes early in reovirus infection. To better understand the minimal requirements of viral inclusion formation, we expressed sigma NS, mu NS, and sigma 3 alone and in combination in the absence of viral infection. In contrast to its concentration in inclusion structures during reovirus replication, sigma NS expressed in cells in the absence of infection is distributed diffusely throughout the cytoplasm and does not form structures that resemble viral inclusions. Expressed sigma NS is functional as it complements the defect in temperature-sensitive, sigma NS-mutant virus tsE320. In both transfected and infected cells, mu NS is found in punctate cytoplasmic structures and sigma 3 is distributed diffusely in the cytoplasm and the nucleus. The subcellular localization of mu NS and sigma 3 is not altered when the proteins are expressed together or with sigma NS. However, when expressed with micro NS, sigma NS colocalizes with mu NS to punctate structures similar in morphology to inclusion structures observed early in viral replication. During reovirus infection, both sigma NS and mu NS are detectable 4 h after adsorption and colocalize to punctate structures throughout the viral life cycle. In concordance with these results, sigma NS interacts with mu NS in a yeast two-hybrid assay and by coimmunoprecipitation analysis. These data suggest that sigma NS and mu NS are the minimal viral components required to form inclusions, which then recruit other reovirus proteins and RNA to initiate viral genome replication.

Crystal structure of human junctional adhesion molecule 1: implications for reovirus binding

Reovirus attachment to cells is mediated by the binding of viral attachment protein sigma 1 to junctional adhesion molecule 1 (JAM1). The crystal structure of the extracellular region of human JAM1 (hJAM1) reveals two concatenated Ig-type domains with a pronounced bend at the domain interface. Two hJAM1 molecules form a dimer that is stabilized by extensive ionic and hydrophobic contacts between the N-terminal domains. This dimeric arrangement is similar to that observed previously in the murine homolog of JAM1, indicating physiologic relevance. However, differences in the dimeric structures of hJAM1 and murine JAM1 suggest that the interface is dynamic, perhaps as a result of its ionic nature. We demonstrate that hJAM1, but not the related proteins hJAM2 and hJAM3, serves as a reovirus receptor, which provides insight into sites in hJAM1 that likely interact with sigma 1. In addition, we present evidence that the previously reported structural homology between sigma 1 and the adenovirus attachment protein, fiber, also extends to their respective receptors, which form similar dimeric structures. Because both receptors are located at regions of cell-cell contact, this similarity suggests that reovirus and adenovirus use conserved mechanisms of entry and pathways of infection.

Pneumocystis carinii pneumonia in a girl with a midbrain glioma

A 7-year-old girl with a midbrain glioma contracted Pneumocystis carinii pneumonia (PCP) in the absence of cytotoxic or corticosteroid therapy. Gliomas are known to cause immunosuppression, and PCP prophylaxis should be considered for patients with these tumors.

Recurrent pneumococcal arthritis as the presenting manifestation of X-linked agammaglobulinemia

Pneumococcal arthritis in children older than 24 months is unusual and can suggest underlying immunodeficiency. We report a case of recurrent pneumococcal arthritis as the presenting manifestation of X-linked agammaglobulinemia.

Retrovirus mediated gene transfer of the self antigen MBP into the bone marrow of mice alters resistance to experimental autoimmune encephalomyelitis

Experimental autoimmune encephalomyelitis (EAE) is a prototypic model of organ specific autoimmunity. MHC class II restricted T-cells directed against myelin basic protein (MBP) have been shown to cause EAE in susceptible strains of mice. We have asked whether the introduction of a gene encoding an autoantigen (MBP) into the hematopoetic stem cells of mice would result in tolerance to that protein. We have introduced cDNA encoding the 21.5 kDa isoform of MBP into the hematopoetic stem cells of B10.PL (73NS), SJL, and B10 mice by retrovirus-mediated gene transfer. Our experiments show expression of proviral MBP in peripheral blood and thymus following transplantation of genetically modified stem cells. Such expression does not result in deletion of MBP-specific T cells or tolerance to MBP, nor does it alter susceptibility to MBP-induced EAE in susceptible strains B10.PL and SJL. However, retrovirus-mediated gene transfer resulted in resistant B10 mice developing mild EAE. This report demonstrates that autoreactive MBP-specific T cells can be selected in the presence of endogenous antigen or an MBP-encoding retrovirus.

The role of the leader sequence coding region in expression and assembly of bacteriorhodopsin

Bacterio-opsin is made as a precursor in Halobacterium halobium, which has 13 additional residues at the amino terminus. The codons for these residues have been proposed to form a hairpin structure in the mRNA and play a role in ribosome binding; the leader peptide sequence also has been proposed to have a role in membrane insertion of bacteriorhodopsin (BR). We have made mutations in the bop gene region coding for the leader sequence and expressed the mutant genes in an H. halobium mutant lacking wild-type BR. The leader sequence coding region was found to be important for the stability of the mRNA and for its efficient translation. Single base substitutions in this region that did not affect the amino acid sequence caused significant reductions in protein expression. Deletion of the leader region resulted in unstable mRNA and almost no BR production. Introduction of a new ribosome-binding sequence within the coding region of the mature protein restored mRNA stability and some protein expression. Protein made without the leader peptide was properly assembled in the membrane.

Purified GPI-anchored CD4DAF as a receptor for HIV-mediated gene transfer

CD4 is the major cellular receptor for the human immunodeficiency virus (HIV). A hybrid gene encoding the extracellular domains of CD4, linked to the sequence encoding the membrane attachment region of the glycosylphosphatidylinositol (GPI)-anchored protein decay accelerating factor (DAF) was stably transfected into HeLa cells. The resultant cell line (T4HD) expressed GPI-anchored CD4DAF at high levels and was susceptible to gene transfer with a recombinant HIV vector. In an effort to expand the spectrum of cells susceptible to HIV gene transfer, CD4DAF was released from the surface of the T4HD cell line by detergent lysis, purified by immunoaffinity chromatography, and reincorporated into native HeLa cells. Incorporation occurred via the GPI anchor as evidenced by cleavage with phosphatidylinositol-specific phospholipase C. More than 95% of the CD4DAF-treated HeLa cells were CD4-positive by flow cytometry, and kinetic analysis demonstrated that over 75% of the fusion protein remained anchored to the cell membrane after 90 min at 37 degrees C. The purified protein retained its ability to bind the envelope protein of HIV. When incorporated, it bound fluorescein isothiocyanate (FITC)-conjugated gp120, and in its soluble form blocked transduction of CD4-positive cells incubated with an HIV-derived vector containing the Neo gene. In contrast to the T4HD cells, exposure of CD4DAF-treated cells to the Neo HIV vector yielded only transient neomycin-resistant colonies. These results suggest that endogenous synthesis of the CD4 molecule may be necessary for successful HIV genomic integration.