Waning mumps IgG antibody and incomplete IgG avidity maturation may increase susceptibility to mumps virus infection in some vaccinees. To measure mumps IgG avidity, serum specimens serially diluted to the endpoint were incubated on a commercial mumps-specific IgG enzyme immunoassay and treated with the protein denaturant diethylamine (60 mM, pH 10). End titer avidity indices (etAIs [percent ratio of detected diethylamine-resistant IgG at endpoint]) were calculated. Unpaired serum specimens (n = 108) from 15-month-old children living in a low-incidence setting were collected 1 month and 2 years after the first measles, mumps, and rubella vaccine dose (MMR1) and tested for mumps avidity. Per the receiver operating characteristic curve, the avidity assay is accurate (area under the curve, 0.994; 95% confidence interval [CI], 0.956 to 1.000), 96.5% sensitive (95% CI, 87.9 to 99.6%), and 92.2% specific (95% CI, 81.1 to 97.8%) at an etAI of 30%. When 9 sets of paired serum specimens collected 1 to 60 months post-MMR1 were tested for mumps and measles IgG avidity using comparable methods, the mumps etAI increased from 11% to 40 to 60% in 6 months. From 6 to 60 months, avidity was sustained at a mean etAI of 50% (95% CI, 46 to 54%), significantly lower (P < 0.0001) than the mean measles etAI of 80% (95% CI, 74 to 86%). Mean etAIs in children 2 years post-MMR1 (n = 51), unvaccinated adults with distant mumps disease (n = 29), and confirmed mumps cases (n = 23) were 54, 62, and 57%, respectively. A mumps-specific endpoint avidity assay was developed and validated, and mumps avidity was determined to be generally sustained at etAIs of 40 to 60%, reaching etAIs of >80% in some individuals.IMPORTANCE Numerous outbreaks of mumps have occurred in the United States among two-dose measles-mumps-rubella (MMR)-vaccinated populations since 2006. The avidity of mumps-specific IgG antibodies may affect susceptibility to mumps virus infection in some vaccinated individuals. To accurately measure mumps avidity, we developed and validated a mumps-specific IgG avidity assay that determines avidity at the endpoint titer of serially diluted serum specimens, providing results that are independent of IgG concentration. At low antibody titers, endpoint methods are considered more accurate than methods that determine avidity at a single dilution. We determined that 6 months after the first MMR dose, mumps IgG avidity is high and generally sustained at avidity indices of 40 to 60%, reaching values of >80% in some individuals. Additionally, 4% (4/103) of individuals had avidity indices of </=30% (low avidity) 2 years after vaccination. Inadequate mumps avidity maturation may be one factor influencing susceptibility to mumps virus infection among previously vaccinated or naturally infected individuals.

Background: Recent mumps outbreaks among 2-dose measles mumps rubella (MMR) vaccine recipients have raised questions regarding the potential benefits of a third dose of vaccine (MMR3). If MMR3 provides a sustained elevation in mumps antibody, it may be beneficial for certain at-risk groups or as an outbreak control measure. Methods: Sera were collected immediately prior to MMR3 and at 1 month and 1 year post-MMR3 from 656 healthy adults aged 18-28 years in a nonoutbreak setting. Immunoglobulin G (IgG) was measured by enzyme-linked immunosorbent assay (ELISA) using whole mumps virus (commercial ELISA), hemagglutinin (HN; major neutralizing target), and nucleoprotein (NP; immunodominant) antigens. ELISA measurements were compared with in vitro plaque reduction neutralization (PRN) titers, and baseline antibody was compared with post-MMR3 levels. Results: There were modest but statistically significant (P < .05) increases in mumps antibody at 1 month post-MMR3 by all 3 ELISA methods and by PRN titer. At 1 year post-MMR3, mumps antibody declined toward baseline but remained elevated (P < .05). The correlation between PRN titers and ELISA measurements was poor (r(2) = .49), although sera with the highest amount of HN IgG also had the highest PRN titers. Conclusions: Individuals with the lowest baseline PRN titers had the largest increase in frequency of samples that became positive for HN and NP by ELISA. A third dose of MMR may benefit certain individuals with a low level of mumps virus-neutralizing antibody, especially in the context of an outbreak or other high-risk setting. Additionally, poor correlation among serologic tests does not allow effective prediction of PRN titer by ELISA.

Neutralizing antibodies are assumed to be essential for protection against mumps virus infection, but their measurement is labor and time intensive. For this reason ELISA assays are typically used to measure mumps specific IgG. However, since there is poor correlation between mumps neutralization titers and ELISA assays that measure the presence of mumps specific IgG, ELISA assays that better correlate with neutralization are needed. To address this issue, we measured mumps antibody by plaque reduction neutralization, by a commercial ELISA (whole-virus antigen), and by ELISAs specific for the mumps nucleoprotein and hemagglutinin. The results indicate that differences in the antibody response to the individual mumps proteins could partially explain the lack of correlation among various serologic tests. Furthermore, the data indicate that some seropositive individuals have low levels of neutralizing antibody. If neutralizing antibody is important for protection, this suggests that previous estimates of immunity based on whole-virus ELISA may be overstated.

CONTEXT: Early in the 2009 pandemic influenza A (H1N1) experience, children aged 5 to 17 years were determined to be disproportionately affected compared with recent influenza seasons. OBJECTIVE: To characterize the pandemic among school-aged children, to enable timely influenza outbreak identification, and to determine which school-based influenza surveillance indicator correlated most closely with a laboratory-based standard influenza indicator (standard) and, therefore, might be most useful for future school-based influenza surveillance. DESIGN: During the 2009-2010 school year, we monitored students using 3 different surveillance indicators: (1) all-cause absenteeism, (2) influenza-like illness (ILI)-related absenteeism, (3) and ILI-related school health office visits. Thresholds were set for each indicator to identify individual school outbreaks. Each surveillance indicator was compared with the standard, confirmed influenza cases among hospitalized patients. SETTING: Tri-County (Denver metropolitan area), Colorado. PARTICIPANTS: Prekindergarten through 12th-grade students in public schools. MAIN OUTCOME MEASURES: Correlation coefficients comparing each influenza surveillance indicator with the standard and graphs comparing weekly rates for each influenza surveillance indicator or weekly outbreak counts with the standard. RESULTS: Correlation between the surveillance indicators and the standard varied greatly. All-cause absenteeism correlated most poorly with the standard (Pearson's r = 0.33) and ILI-related health office visits correlated moderately well (r = 0.63). Influenza-like illness-related absenteeism correlated best (r = 0.92) and could be improved (r = 0.97) by shifting ILI-absenteeism data later by 1 week. Graphs of weekly rates or weekly outbreak counts also illustrated that ILI-related absenteeism correlated best with the standard. CONCLUSIONS: For influenza surveillance among school-aged children, when feasible, we recommend using ILI-related absenteeism, which correlated best and its rate peaked more than 1 week sooner than the standard. The other 2 surveillance indicators might be useful in certain situations, such as when resources are limited.

In 2010, 41 patients ill with Escherichia coli O157:H7 isolates determined to be indistinguishable by pulsed-field gel electrophoresis were identified among residents of five Southwestern U.S. states. A majority of patients reported consuming complimentary samples of aged raw-milk Gouda cheese at national warehouse chain store locations; sampling Gouda cheese was significantly associated with illness (odds ratio, 9.0; 95 % confidence interval, 1.7 to 47). Several Gouda samples yielded the O157:H7 outbreak strain, confirming the food vehicle and source of infections. Implicated retail food-sampling operations were inconsistently regulated among affected states, and sanitation deficiencies were common among sampling venues. Inspection of the cheese manufacturer indicated deficient sanitation practices and insufficient cheese curing times. Policymakers should continue to reexamine the adequacy and enforcement of existing rules intended to ensure the safety of raw-milk cheeses and retail food sampling. Additional research is necessary to clarify the food safety hazards posed to patrons who consume free food samples while shopping.

Tri-County Health Department studied needlestick injury (NSI) risks in pandemic influenza A (H1N1) mass vaccination clinics through incident reports and an Internet-based vaccinator survey. The mass vaccination clinic NSI rate was 4.9 times the mean rate observed during Tri-County Health Department's 2003 to 2009 routine vaccination clinics. There was also a trend of increased risk for NSI with vaccination inexperience. These findings can be used to improve future mass vaccination clinic safety.

Waning immunity or secondary vaccine failure (SVF) has been anticipated by some as a challenge to global measles elimination efforts. Although such cases are infrequent, measles virus (MeV) infection can occur in vaccinated individuals following intense and/or prolonged exposure to an infected individual and may present as a modified illness that is unrecognizable as measles outside of the context of a measles outbreak. The immunoglobulin M response in previously vaccinated individuals may be nominal or fleeting, and viral replication may be limited. As global elimination proceeds, additional methods for confirming modified measles cases may be needed to understand whether SVF cases contribute to continued measles virus (MeV) transmission. In this report, we describe clinical symptoms and laboratory results for unvaccinated individuals with acute measles and individuals with SVF identified during MeV outbreaks. SVF cases were characterized by the serological parameters of high-avidity antibodies and distinctively high levels of neutralizing antibody. These parameters may represent useful biomarkers for classification of SVF cases that previously could not be confirmed as such using routine laboratory diagnostic techniques.

Utah Clinical Guidelines on Prescribing Opioids for Treatment of Pain were produced and made available to medical providers in March 2009. These guidelines were developed by a multidisciplinary consensus panel after a review of existing evidence-based guidelines. Common recommendations were compiled and presented to the panel for review. The guidelines consist of a set of recommendations for both acute and chronic pain. A second panel reviewed existing tools for providers and determined the need for any new tools. The final guidelines include 20 tools for providers to use in their practice. The complete version of the guidelines and the accompanying tools are available at: www.useonlyasdirected.org or www.health.utah.gov/prescription.

BACKGROUND: In 2006, the largest mumps outbreak in the United States in 20 years occurred. To understand prior mumps seroprevalence and factors associated with the presence of antibody to mumps virus, data from the 1999-2004 National Health and Nutrition Examination Survey (NHANES) were analyzed. METHODS: A mumps virus-specific enzyme immunoassay was used to measure the seroprevalence of serum immunoglobulin G (IgG) antibody among NHANES participants aged 6-49 years. Participants were grouped on the basis of 10-year birth cohorts, 95% confidence intervals (CIs) were calculated using SUDAAN software, and logistic regression was used to identify independent predictors. RESULTS: The overall age-adjusted seroprevalence of IgG antibody to mumps virus during 1999-2004 was 90.0% (95% CI, 88.8%-91.1%). Seroprevalence was higher among US-born non-Hispanic blacks (96.4% [95% CI, 95.5%-97.2%]) and non-US-born Mexican Americans (93.7% [95% CI, 92.0%-95.2%]). Seroprevalence was significantly lower in the 1967-1976 birth cohort (85.7% [95% CI, 83.5%-87.8%]). The variables sex, education, and race/ethnicity/birthplace were independent predictors in at least 1 of the birth cohorts. CONCLUSIONS: The overall estimate of 90.0% is at the lower end of the estimated population immunity (90%-92%) needed to achieve herd immunity. Lower seroprevalence among groups suggest that they represent populations at an increased risk. For mumps control, high vaccine coverage and high population immunity must be achieved and maintained.