MD Conference Express ICAAC 2011 - (Page 13)
The results of this study are limited by the fact that it was a retrospective, noncomparative study. There was also a lack of data regarding the MSSA molecular epidemiology in the hospital, the proportion of community-onset bacteremias that were health care-associated, and the proportion of nosocomial bacteremias that were line-related. Dr. Gouliouris concluded from the study that local rates of nosocomial MSSA BSIs have declined since 2006, though not as markedly as those for MRSA. The establishment of a vascular access team and the implementation of line care bundles appear to have had the most impact toward reducing both nosocomial MRSA and MSSA BSIs. MRSA screening and decolonization likely accounted for the greater reductions that were achieved in MRSA BSIs compared with MSSA. Finally, MSSA-targeted interventions may be needed to achieve reductions that are comparable with those for MRSA BSIs.
review. Electronic medical records were examined for demographic information and vaccine status. In all, 132 patients <18 years were included. Vaccination status among children aged ≤12 years at presentation revealed that 85% were fully vaccinated, 7% was under vaccinated, and 8% was unvaccinated (never vaccinated). B. pertussis attack rates were shown to be highest among 8- to 12-year olds, compared with 2- to 7- and 13- to 18year olds (p=0.002, one sample t-test; Table 1). Among children <12 years, a trend toward lower attack rates among fully immunized children versus under- or neverimmunized children was observed, but the difference was not statistically significant. In contrast, children aged 13 to 18 years who were not fully immunized had significantly higher attack rates compared with other age groups (p=0.009). No patients in the cohort were hospitalized or died from their illness. Vaccine effectiveness, a metric of the field performance of the vaccine, was calculated by comparing attack rates between under- and never-immunized versus fully immunized patient groups (of note, effectiveness should not be confused with efficacy, which reflects performance in a prospective placebo-controlled trial). The effectiveness of aP varied by age group: 41% (95% CI, 21% to 54%) and 79% (95% CI, 73% to 84%) within the 2- to 7- and 13- to 18-year olds, respectively, possibly reflecting more recent immunization, but only 24% (95% CI, 0% to 40%) in the 8- to 12- year old age group. Table 1. Peak Attack Rates Observed Among 8- to 12Year Olds.
Age Group 2-7 8-12 13-18 2-18 Attack Rate in Vaccinated Persons* 359 2453 452 1011 Attack Rate in Under and Unvaccinated Persons* 606 3211 2189 2073 p value 0.57 0.43 0.009 0.01
Is the Effectiveness of Acellular Pertussis Vaccine in Pre-Adolescents Insufficient?
Written by Noelle Lake, MD
A retrospective, single-center chart review of the 2010 Bordetella pertussis outbreak in California found that a time interval greater than 3 year since vaccination with acellular pertussis (aP) correlated with increased risk for acquiring the disease. Research assistant Maxwell Witt, Kaiser Permanente Medical Center, San Rafael, California, USA, reported that children between 8 and 12 years had higher attack rates and reduced vaccine effectiveness compared with children aged 2 to 7 and 13 to 18 years, possibly a reflection of greater time since their last aP dose. Since the replacement of whole-cell pertussis vaccine with the better-tolerated aP version in 2002, questions regarding its efficacy and durability have lingered [Zhang L et al. Cochrane Database Syst Rev 2011]. Researchers at San Rafael Kaiser Permanente (KP) Medical Center, led by David Witt, MD, saw the California outbreak as an opportunity to observe aP vaccine performance by age, time since last vaccine, and vaccine status. Between March and October 2010, patients who presented to the San Rafael KP pediatrics department with a severe cough for greater than 1 week and a positive PCR for B. pertussis were considered infected and included in the
The authors concluded that aP is highly effective within 3 years of administration after which its protection may diminish. Should larger studies confirm these findings, additional scheduled dosing or targeted vaccine programs during outbreaks may be proposed. One attendee, however, challenged the relevance of the findings including the use of the phrase “vaccine failure,” arguing that strict case definitions had not been used. In Dr. Witt’s opinion, B. pertussis carriage in the face of a viral illness had not been ruled out and therefore, these results cannot be used to question the efficacy of the vaccine.
Official Peer-Reviewed Highlights from the 51st ICAAC
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Table of Contents for the Digital Edition of MD Conference Express ICAAC 2011
MD Conference Express ICAAC 2011
Contents
Infectious Disease Genomics
Emerging Resistance Among Gram-Negative Pathogens
Procalcitonin-Guided Antibiotic Therapy In Patients with Lower Respiratory Tract Infections
Combination Therapy with Flucytosine Improves Survival in AIDS-Related Cryptococcal Meningitis
CXA-201 Effective Against Common ICU Pathogens
Tigecycline Plus Standard Therapy Is More Effective For Treating Infections in Febrile Neutropenic Cancer Patients
Interventions Aimed at Reducing MRSA BSIs Led to Decreased Rates of Nosocomial MSSA BSIs
Is the Effectiveness of aP Vaccine in Pre-Adolescents Insufficient?
TMC435 Effective in the Treatment of HCV Genotype 1 Infection
HIV
Vaccines
Antibiotic Resistance
Drug Discovery
The Conundrum of MDR TB and Combination Therapy
New Drugs to Treat MDR Pathogens
Immunizations in Reproductive Health
Why Can’t Microbes Just Get Along?
The Role of Adjunctive Steroids in the Treatment of Bacterial Meningitis
Human and Animal Viruses Share “One World” and Emerging Zoonotic Infections Continue to Threaten
MD Conference Express ICAAC 2011
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