Estimation of Influenza Vaccine Effectiveness from Routine Surveillance Data

BACKGROUND: Influenza vaccines are reviewed each year, and often changed, in an effort to maintain their effectiveness against drifted influenza viruses. There is however no regular review of influenza vaccine effectiveness during, or at the end of, Australian influenza seasons. It is possible to use a case control method to estimate vaccine effectiveness from surveillance data when all patients in a surveillance system are tested for influenza and their vaccination status is known. METHODOLOGY/PRINCIPAL FINDINGS: Influenza-like illness (ILI) surveillance is conducted during the influenza season in sentinel general practices scattered throughout Victoria, Australia. Over five seasons 2003-7, data on age, sex and vaccination status were collected and nose and throat swabs were offered to patients presenting within three days of the onset of their symptoms. Swabs were tested using a reverse transcriptase polymerase chain reaction (RT-PCR) test. Those positive for influenza were sent to the World Health Organization (WHO) Collaborating Centre for Reference and Research on Influenza where influenza virus culture and strain identification was attempted. We used a retrospective case control design in five consecutive influenza seasons, and estimated influenza vaccine effectiveness (VE) for patients of all ages to be 53% (95% CI 38-64), but 41% (95% CI 19-57) adjusted for age group and year. The adjusted VE for all adults aged at least 20 years, the age groups for whom a benefit of vaccination could be shown, was 51% (95% CI 34-63). Comparison of VE estimates with vaccine and circulating strain matches across the years did not reveal any significant differences. CONCLUSIONS/SIGNIFICANCE: These estimates support other field studies of influenza vaccine effectiveness, given that theoretical considerations suggest that these values may underestimate true effectiveness, depending on test specificity and the ratio of the influenza ILI attack rate to the non-influenza ILI attack rate. Incomplete recording of vaccination status and under-representation of children in patients from whom a swab was collected limit the data. Improvements have been implemented for prospective studies

Field Effectiveness of Pandemic and 2009-2010 Seasonal Vaccines against 2009-2010 A(H1N1) Influenza: Estimations from Surveillance Data in France

BACKGROUND: In this study, we assess how effective pandemic and trivalent 2009-2010 seasonal vaccines were in preventing influenza-like illness (ILI) during the 2009 A(H1N1) pandemic in France. We also compare vaccine effectiveness against ILI versus laboratory-confirmed pandemic A(H1N1) influenza, and assess the possible bias caused by using non-specific endpoints and observational data. METHODOLOGY AND PRINCIPAL FINDINGS: We estimated vaccine effectiveness by using the following formula: VE  =  (PPV-PCV)/(PPV(1-PCV)) × 100%, where PPV is the proportion vaccinated in the population and PCV the proportion of vaccinated influenza cases. People were considered vaccinated three weeks after receiving a dose of vaccine. ILI and pandemic A(H1N1) laboratory-confirmed cases were obtained from two surveillance networks of general practitioners. During the epidemic, 99.7% of influenza isolates were pandemic A(H1N1). Pandemic and seasonal vaccine uptakes in the population were obtained from the National Health Insurance database and by telephonic surveys, respectively. Effectiveness estimates were adjusted by age and week. The presence of residual biases was explored by calculating vaccine effectiveness after the influenza period. The effectiveness of pandemic vaccines in preventing ILI was 52% (95% confidence interval: 30-69) during the pandemic and 33% (4-55) after. It was 86% (56-98) against confirmed influenza. The effectiveness of seasonal vaccines against ILI was 61% (56-66) during the pandemic and 19% (-10-41) after. It was 60% (41-74) against confirmed influenza. CONCLUSIONS: The effectiveness of pandemic vaccines in preventing confirmed pandemic A(H1N1) influenza on the field was high, consistently with published findings. It was significantly lower against ILI. This is unsurprising since not all ILI cases are caused by influenza. Trivalent 2009-2010 seasonal vaccines had a statistically significant effectiveness in preventing ILI and confirmed pandemic influenza, but were not better in preventing confirmed pandemic influenza than in preventing ILI. This lack of difference might be indicative of selection bias

Uterine mullerian adenosarcoma with sarcomatous overgrowth fatal recurrence within two weeks of diagnosis: a case report

Mullerian adenosarcoma with sarcomatous overgrowth (MASO) is a rare variant of uterine sarcomas, associated with postoperative recurrence, metastases and a fatal outcome. The mean age at diagnosis is 54.5 years. A 37-year-old nullipara presented with irregular vaginal bleeding, a normal pelvic examination, and an initially negative ultrasound. Repeat ultrasound one month later revealed an 11-cm heterogeneous pelvic mass. She underwent total abdominal hysterectomy and bilateral salpingo-oophorectomy. Pathology confirmed uterine MASO. Computed tomography 2 weeks postoperatively showed a huge mass compatible with recurrence. Patient died 2 weeks later. MASO is rarely diagnosed in women in their 4th decade. This case stresses that these aggressive tumors should be considered in the differential of patients with vaginal bleeding and pelvic masses irrespective of their age

Implications for registry-based vaccine effectiveness studies from an evaluation of an immunization registry: A cross-sectional study

<p>Abstract</p> <p>Background</p> <p>Population-based electronic immunization registries create the possibility of using registry data to conduct vaccine effectiveness studies which could have methodological advantages over traditional observational studies. For study validity, the base population would have to be clearly defined and the immunization status of members of the population accurately recorded in the registry. We evaluated a city-wide immunization registry, focusing on its potential as a tool to study pertussis vaccine effectiveness, especially in adolescents.</p> <p>Methods</p> <p>We conducted two evaluations – one in sites that were active registry participants and one in sites that had implemented an electronic medical record with plans for future direct data transfer to the registry – of the ability to match patients' medical records to registry records and the accuracy of immunization records in the registry. For each site, records from current pediatric patients were chosen randomly. Data regarding pertussis-related immunizations, clinic usage, and demographic and identifying information were recorded; for 11–17-year-old subjects, information on MMR, hepatitis B, and varicella immunizations was also collected. Records were then matched, when possible, to registry records. For records with a registry match, immunization data were compared.</p> <p>Results</p> <p>Among 350 subjects from sites that were current registry users, 307 (87.7%) matched a registry record. Discrepancies in pertussis-related data were common for up-to-date status (22.6%), number of immunizations (34.7%), dates (10.2%), and formulation (34.4%). Among 442 subjects from sites that planned direct electronic transfer of immunization data to the registry, 393 (88.9%) would have matched a registry record; discrepancies occurred frequently in number of immunizations (11.9%), formulation (29.1%), manufacturer (94.4%), and lot number (95.1%.) Inability to match and immunization discrepancies were both more common in subjects who were older at their first visit to the provider site. For 11–17-year-old subjects, discrepancies were also common for MMR, hepatitis B, and varicella vaccination data.</p> <p>Conclusion</p> <p>Provider records frequently could not be matched to registry records or had discrepancies in key immunization data. These issues were more common for older children and were present even with electronic data transfer. These results highlight general challenges that may face investigators wishing to use registry-based immunization data for vaccine effectiveness studies, especially in adolescents.</p

Seasonal Influenza Vaccine and Protection against Pandemic (H1N1) 2009-Associated Illness among US Military Personnel

INTRODUCTION: A novel A/H1N1 virus is the cause of the present influenza pandemic; vaccination is a key countermeasure, however, few data assessing prior seasonal vaccine effectiveness (VE) against the pandemic strain of H1N1 (pH1N1) virus are available. MATERIALS AND METHODS: Surveillance of influenza-related medical encounter data of active duty military service members stationed in the United States during the period of April-October 2009 with comparison of pH1N1-confirmed cases and location and date-matched controls. Crude odds ratios (OR) and VE estimates for immunized versus non-immunized were calculated as well as adjusted OR (AOR) controlling for sex, age group, and history of prior influenza vaccination. Separate stratified VE analyses by vaccine type (trivalent inactivated [TIV] or live attenuated [LAIV]), age groups and hospitalization status were also performed. For the period of April 20 to October 15, 2009, a total of 1,205 cases of pH1N1-confirmed cases were reported, 966 (80%) among males and over one-half (58%) under 25 years of age. Overall VE for service members was found to be 45% (95% CI, 33 to 55%). Immunization with prior season's TIV (VE = 44%, 95% CI, 32 to 54%) as well as LAIV (VE = 24%, 95% CI, 6 to 38%) were both found to be associated with protection. Of significance, VE against a severe disease outcome was higher (VE = 62%, 95% CI, 14 to 84%) than against milder outcomes (VE = 42%, 95% CI, 29 to 53%). CONCLUSION: A moderate association with protection against clinically apparent, laboratory-confirmed Pandemic (H1N1) 2009-associated illness was found for immunization with either TIV or LAIV 2008-09 seasonal influenza vaccines. This association with protection was found to be especially apparent for severe disease as compared to milder outcome, as well as in the youngest and older populations. Prior vaccination with seasonal influenza vaccines in 2004-08 was also independently associated with protection

Vaccination coverage and timeliness in three South African areas: a prospective study

<p>Abstract</p> <p>Background</p> <p>Timely vaccination is important to induce adequate protective immunity. We measured vaccination timeliness and vaccination coverage in three geographical areas in South Africa.</p> <p>Methods</p> <p>This study used vaccination information from a community-based cluster-randomized trial promoting exclusive breastfeeding in three South African sites (Paarl in the Western Cape Province, and Umlazi and Rietvlei in KwaZulu-Natal) between 2006 and 2008. Five interview visits were carried out between birth and up to 2 years of age (median follow-up time 18 months), and 1137 children were included in the analysis. We used Kaplan-Meier time-to-event analysis to describe vaccination coverage and timeliness in line with the Expanded Program on Immunization for the first eight vaccines. This included Bacillus Calmette-Guérin (BCG), four oral polio vaccines and 3 doses of the pentavalent vaccine which protects against diphtheria, pertussis, tetanus, hepatitis B and Haemophilus influenzae type B.</p> <p>Results</p> <p>The proportion receiving all these eight recommended vaccines were 94% in Paarl (95% confidence interval [CI] 91-96), 62% in Rietvlei (95%CI 54-68) and 88% in Umlazi (95%CI 84-91). Slightly fewer children received all vaccines within the recommended time periods. The situation was worst for the last pentavalent- and oral polio vaccines. The hazard ratio for incomplete vaccination was 7.2 (95%CI 4.7-11) for Rietvlei compared to Paarl.</p> <p>Conclusions</p> <p>There were large differences between the different South African sites in terms of vaccination coverage and timeliness, with the poorer areas of Rietvlei performing worse than the better-off areas in Paarl. The vaccination coverage was lower for the vaccines given at an older age. There is a need for continued efforts to improve vaccination coverage and timeliness, in particular in rural areas.</p> <p>Trial registration number</p> <p>ClinicalTrials.gov: <a href="http://clinicaltrials.gov/ct2/show/NCT00397150">NCT00397150</a></p

Transcutaneous flow related variables measured in vivo: the effects of gender

BACKGOUND: The identification of potential sources of error is a crucial step for any new assessment technique. This is the case for transcutaneous variables, such as flow and arterial gases, which have been applied as functional indicators of various aspects of human health. Regarding gender, a particular subject-related determinant, it is often claimed that women present higher transcutaneous oxygen pressure (tcpO(2)) values than men. However, the statistical significance of this finding is still uncertain. METHODS: The haemodynamical-vascular response to a local reactive hyperaemia procedure (the tourniquet cuff manoeuvre) was studied in two previously selected group of volunteers (n = 16; 8 women and 8 men). The effect of gender was assessed under standardised experimental conditions, using the transcutaneous flow-related variables tcpO(2)-tcpCO(2) and Laser-doppler Flowmetry (LDF). RESULTS: Regarding tcpO(2), statistically significant differences between genders were not found, although higher values were consistently found for the gases in the female group. Regarding LDF, high statistically significant differences (p < 0.005) were found, with the men's group presenting the highest values and variability. Other derived parameters used to characterise the vascular response following the cuff-deflation (t-peak) were similar in both groups. CONCLUSIONS: The relative influence of gender was not clearly demonstrated using these experimental conditions. However the gender-related LDF differences suggest that further investigation should be done on this issue. Perhaps in the presence of certain pathological disparities involving peripheral vascular regulation, other relationships may be found between these variables