Last data update: Sep 23, 2024. (Total: 47723 publications since 2009)
Records 1-11 (of 11 Records) |
Query Trace: Soldan K [original query] |
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The Great Chlamydia Control Bake Off: the same ingredients (evidence) but different recipes for success
Soldan K , Anyalechi GE , Kreisel KM , Hocking JS , Bernstein K . Sex Transm Infect 2021 97 (7) 473-475 Successful baking requires careful measurement, the precise mixing of ingredients and an attentive eye while the mixture is in the oven. However, the environment may have an impact on the final product. Humidity, quality of ingredients, type of oven used and altitude can all mean the difference between a perfect cake and a goopy mess. Although chlamydia control may seem quite different from baking, there are some important parallels, notably the context in which control programmes are developed, implemented and evaluated. The same inputs and approaches applied in different contexts may produce drastically different results. | | van Bergen et al1 describe the methods of and conclusions from addressing the question ‘Where to go to in Chlamydia control?’ for the Netherlands in this issue of Sexually Transmitted Infections. |
Population-Level Effects of Human Papillomavirus Vaccination Programs on Infections with Nonvaccine Genotypes.
Mesher D , Soldan K , Lehtinen M , Beddows S , Brisson M , Brotherton JM , Chow EP , Cummings T , Drolet M , Fairley CK , Garland SM , Kahn JA , Kavanagh K , Markowitz L , Pollock KG , Soderlund-Strand A , Sonnenberg P , Tabrizi SN , Tanton C , Unger E , Thomas SL . Emerg Infect Dis 2016 22 (10) 1732-40 We analyzed human papillomavirus (HPV) prevalences during prevaccination and postvaccination periods to consider possible changes in nonvaccine HPV genotypes after introduction of vaccines that confer protection against 2 high-risk types, HPV16 and HPV18. Our meta-analysis included 9 studies with data for 13,886 girls and women ≤19 years of age and 23,340 women 20-24 years of age. We found evidence of cross-protection for HPV31 among the younger age group after vaccine introduction but little evidence for reductions of HPV33 and HPV45. For the group this same age group, we also found slight increases in 2 nonvaccine high-risk HPV types (HPV39 and HPV52) and in 2 possible high-risk types (HPV53 and HPV73). However, results between age groups and vaccines used were inconsistent, and the increases had possible alternative explanations; consequently, these data provided no clear evidence for type replacement. Continued monitoring of these HPV genotypes is important. |
Experiences with insecticide-treated curtains: a qualitative study in Iquitos, Peru
Paz-Soldan VA , Bauer KM , Lenhart A , Cordova Lopez JJ , Elder JP , Scott TW , McCall PJ , Kochel TJ , Morrison AC . BMC Public Health 2016 16 582 BACKGROUND: Dengue is an arthropod-borne viral disease responsible for approximately 400 million infections annually; the only available method of prevention is vector control. It has been previously demonstrated that insecticide treated curtains (ITCs) can lower dengue vector infestations in and around houses. As part of a larger trial examining whether ITCs could reduce dengue transmission in Iquitos, Peru, the objective of this study was to characterize the participants' experience with the ITCs using qualitative methods. METHODS: Knowledge, attitudes, and practices (KAP) surveys (at baseline, and 9 and 27 months post-ITC distribution, with n = 593, 595 and 511, respectively), focus group discussions (at 6 and 12 months post-ITC distribution, with n = 18 and 33, respectively), and 11 one-on-one interviews (at 12 months post-distribution) were conducted with 605 participants who received ITCs as part of a cluster-randomized trial. RESULTS: Focus groups at 6 months post-ITC distribution revealed that individuals had observed their ITCs to function for approximately 3 months, after which they reported the ITCs were no longer working. Follow up revealed that the ITCs required re-treatment with insecticide at approximately 1 year post-distribution. Over half (55.3 %, n = 329) of participants at 9 months post-ITC distribution and over a third (34.8 %, n = 177) at 27 months post-ITC distribution reported perceiving a decrease in the number of mosquitoes in their home. The percentage of participants who would recommend ITCs to their family or friends in the future remained high throughout the study (94.3 %, n = 561 at 9 months and 94.6 %, n = 488 at 27 months post-distribution). When asked why, participants reported that ITCs were effective at reducing mosquitoes (81.6 and 37.8 %, at 9 and 27 months respectively), that they prevent dengue (5.7 and 51.2 %, at 9 and 27 months), that they are "beautiful" (5.9 and 3.1 %), as well as other reasons (6.9 and 2.5 %). CONCLUSION: ITCs have substantial potential for long term dengue vector control because they are liked by users, both for their perceived effectiveness and for aesthetic reasons, and because they require little proactive behavioral effort on the part of the users. Our results highlight the importance of gathering process (as opposed to outcome) data during vector control studies, without which researchers would not have become aware that the ITCs had lost effectiveness early in the trial. |
Factors associated with correct and consistent Insecticide treated curtain use in Iquitos, Peru
Paz-Soldan VA , Bauer K , Morrison AC , Cordova Lopez JJ , Izumi K , Scott TW , Elder JP , Alexander N , Halsey ES , McCall PJ , Lenhart A . PLoS Negl Trop Dis 2016 10 (3) e0004409 Dengue is an arthropod-borne virus of great public health importance, and control of its mosquito vectors is currently the only available method for prevention. Previous research has suggested that insecticide treated curtains (ITCs) can lower dengue vector infestations in houses. This observational study investigated individual and household-level socio-demographic factors associated with correct and consistent use of ITCs in Iquitos, Peru. A baseline knowledge, attitudes, and practices (KAP) survey was administered to 1,333 study participants, and ITCs were then distributed to 593 households as part of a cluster-randomized trial. Follow up KAP surveys and ITC-monitoring checklists were conducted at 9, 18, and 27 months post-ITC distribution. At 9 months post-distribution, almost 70% of ITCs were hanging properly (e.g. hanging fully extended or tied up), particularly those hung on walls compared to other locations. Proper ITC hanging dropped at 18 months to 45.7%. The odds of hanging ITCs correctly and consistently were significantly greater among those participants who were housewives, knew three or more correct symptoms of dengue and at least one correct treatment for dengue, knew a relative or close friend who had had dengue, had children sleeping under a mosquito net, or perceived a change in the amount of mosquitoes in the home. Additionally, the odds of recommending ITCs in the future were significantly greater among those who perceived a change in the amount of mosquitoes in the home (e.g. perceived the ITCs to be effective). Despite various challenges associated with the sustained effectiveness of the selected ITCs, almost half of the ITCs were still hanging at 18 months, suggesting a feasible vector control strategy for sustained community use. |
How do changes in the population tested for chlamydia over time affect observed trends in chlamydia positivity? Analysis of routinely collected data from young women tested for chlamydia in family planning clinics in the Pacific Northwest (USA), between 2003 and 2010
Woodhall SC , Torrone L , Fine D , Salomon SG , Nakatsukasa-Ono W , Soldan K , Weinstock H . Sex Health 2015 12 (6) 512-9 BACKGROUND: The proportion of chlamydia tests that are positive (positivity) is dependent on the population tested and the test technology used. The way in which changes in these variables might affect trends in positivity over time is investigated. METHODS: Data from 15- to 24-year-old women tested for chlamydia in family planning clinics participating in the Infertility Prevention Project in the Pacific Northwest, United States (USA Public Health Service Region X) during 2003-2010 (n = 590557) were analysed. Trends in positivity and in test, demographic and sexual behaviour variables were identified. Unadjusted and adjusted trends in chlamydia positivity were calculated using logistic regression. RESULTS: The proportion of tests carried out using nucleic acid amplification tests (NAATs) increased dramatically during the analysis period in two states. Smaller changes in demographic and behavioural characteristics were seen. Controlling for test technology used had the largest effect on the trend in testing positive per year, leading to a fall in the calculated odds ratio of testing positive from 1.06 to 1.02 in Oregon, and from 1.07 to 1.02 in Idaho. Controlling for other variables had minimal effect on chlamydia positivity trends. CONCLUSIONS: Changes in NAAT use had a large effect on observed trends in chlamydia positivity over time in the two states where NAATs were introduced during the analysis period. While trends in chlamydia positivity may be a useful metric for monitoring chlamydia burden, it is important to consider changes in test type when interpreting these data. |
Dengue knowledge and preventive practices in Iquitos, Peru
Paz-Soldan VA , Morrison AC , Cordova Lopez JJ , Lenhart A , Scott TW , Elder JP , Sihuincha M , Kochel TJ , Halsey ES , Astete H , McCall PJ . Am J Trop Med Hyg 2015 93 (6) 1330-1337 As part of a cluster-randomized trial to evaluate insecticide-treated curtains for dengue prevention in Iquitos, Peru, we surveyed 1,333 study participants to examine knowledge and reported practices associated with dengue and its prevention. Entomological data from 1,133 of these households were linked to the survey. Most participants knew that dengue was transmitted by mosquito bite (85.6%), but only few (18.6%) knew that dengue vectors bite during daytime. Most commonly recognized dengue symptoms were fever (86.6%), headache (76.4%), and muscle/joint pain (67.9%). Most commonly reported correct practices for mosquito control were cleaning homes (61.6%), using insecticide sprays (23%), and avoiding having standing water at home (12.3%). Higher education was associated with higher knowledge about dengue, including transmission and vector control. Higher socioeconomic status was associated with increased reported use of preventive practices requiring money expenditure. We were less likely to find Aedes aegypti eggs, larvae, or pupae in households that had < 5-year-old children at home. Although dengue has been transmitted in Iquitos since the 1990s and the Regional Health Authority routinely fumigates households, treats domestic water containers with larvicide, and issues health education messages through mass media, knowledge of dengue transmission and household practices for prevention could be improved. |
Population-level impact and herd effects following human papillomavirus vaccination programmes: a systematic review and meta-analysis
Drolet M , Benard E , Boily MC , Ali H , Baandrup L , Bauer H , Beddows S , Brisson J , Brotherton JM , Cummings T , Donovan B , Fairley CK , Flagg EW , Johnson AM , Kahn JA , Kavanagh K , Kjaer SK , Kliewer EV , Lemieux-Mellouki P , Markowitz L , Mboup A , Mesher D , Niccolai L , Oliphant J , Pollock KG , Soldan K , Sonnenberg P , Tabrizi SN , Tanton C , Brisson M . Lancet Infect Dis 2015 15 (5) 565-80 BACKGROUND: Human papillomavirus (HPV) vaccination programmes were first implemented in several countries worldwide in 2007. We did a systematic review and meta-analysis to assess the population-level consequences and herd effects after female HPV vaccination programmes, to verify whether or not the high efficacy reported in randomised controlled clinical trials are materialising in real-world situations. METHODS: We searched the Medline and Embase databases (between Jan 1, 2007 and Feb 28, 2014) and conference abstracts for time-trend studies that analysed changes, between the pre-vaccination and post-vaccination periods, in the incidence or prevalence of at least one HPV-related endpoint: HPV infection, anogenital warts, and high-grade cervical lesions. We used random-effects models to derive pooled relative risk (RR) estimates. We stratified all analyses by age and sex. We did subgroup analyses by comparing studies according to vaccine type, vaccination coverage, and years since implementation of the vaccination programme. We assessed heterogeneity across studies using I2 and chi2 statistics and we did trends analysis to examine the dose-response association between HPV vaccination coverage and each study effect measure. FINDINGS: We identified 20 eligible studies, which were all undertaken in nine high-income countries and represent more than 140 million person-years of follow-up. In countries with female vaccination coverage of at least 50%, HPV type 16 and 18 infections decreased significantly between the pre-vaccination and post-vaccination periods by 68% (RR 0.32, 95% CI 0.19-0.52) and anogenital warts decreased significantly by 61% (0.39, 0.22-0.71) in girls 13-19 years of age. Significant reductions were also recorded in HPV types 31, 33, and 45 in this age group of girls (RR 0.72, 95% CI 0.54-0.96), which suggests cross-protection. Additionally, significant reductions in anogenital warts were also reported in boys younger than 20 years of age (0.66 [95% CI 0.47-0.91]) and in women 20-39 years of age (0.68 [95% CI 0.51-0.89]), which suggests herd effects. In countries with female vaccination coverage lower than 50%, significant reductions in HPV types 16 and 18 infection (RR 0.50, 95% CI 0.34-0.74]) and in anogenital warts (0.86 [95% CI 0.79-0.94]) occurred in girls younger than 20 years of age, with no indication of cross-protection or herd effects. INTERPRETATION: Our results are promising for the long-term population-level effects of HPV vaccination programmes. However, continued monitoring is essential to identify any signals of potential waning efficacy or type-replacement. FUNDING: The Canadian Institutes of Health Research. |
Time-varying, serotype-specific force of infection of dengue virus
Reiner RC Jr , Stoddard ST , Forshey BM , King AA , Ellis AM , Lloyd AL , Long KC , Rocha C , Vilcarromero S , Astete H , Bazan I , Lenhart A , Vazquez-Prokopec GM , Paz-Soldan VA , McCall PJ , Kitron U , Elder JP , Halsey ES , Morrison AC , Kochel TJ , Scott TW . Proc Natl Acad Sci U S A 2014 111 (26) E2694-702 Infectious disease models play a key role in public health planning. These models rely on accurate estimates of key transmission parameters such as the force of infection (FoI), which is the per-capita risk of a susceptible person being infected. The FoI captures the fundamental dynamics of transmission and is crucial for gauging control efforts, such as identifying vaccination targets. Dengue virus (DENV) is a mosquito-borne, multiserotype pathogen that currently infects approximately 390 million people a year. Existing estimates of the DENV FoI are inaccurate because they rely on the unrealistic assumption that risk is constant over time. Dengue models are thus unreliable for designing vaccine deployment strategies. Here, we present to our knowledge the first time-varying (daily), serotype-specific estimates of DENV FoIs using a spline-based fitting procedure designed to examine a 12-y, longitudinal DENV serological dataset from Iquitos, Peru (11,703 individuals, 38,416 samples, and 22,301 serotype-specific DENV infections from 1999 to 2010). The yearly DENV FoI varied markedly across time and serotypes (0-0.33), as did daily basic reproductive numbers (0.49-4.72). During specific time periods, the FoI fluctuations correlated across serotypes, indicating that different DENV serotypes shared common transmission drivers. The marked variation in transmission intensity that we detected indicates that intervention targets based on one-time estimates of the FoI could underestimate the level of effort needed to prevent disease. Our description of dengue virus transmission dynamics is unprecedented in detail, providing a basis for understanding the persistence of this rapidly emerging pathogen and improving disease prevention programs. |
Human papillomavirus antibody reference reagents for use in postvaccination surveillance serology
Bissett SL , Wilkinson D , Tettmar KI , Jones N , Stanford E , Panicker G , Faust H , Borrow R , Soldan K , Unger ER , Dillner J , Minor P , Beddows S . Clin Vaccine Immunol 2012 19 (3) 449-51 Suitably controlled serosurveillance surveys are essential for evaluating human papillomavirus (HPV) immunization programs. A panel of plasma samples from 18-year-old females was assembled, the majority of the samples being from recipients of the bivalent HPV vaccine. Antibody specificities were evaluated by three independent laboratories, and 3 pools that displayed no antibodies to any HPV type tested or intermediate or high levels of antibody to HPV16, HPV18, HPV31, and HPV45 were created. These pools will be useful as control reagents for HPV serology. |
Danish health register study: a randomised trial with findings about the implementation of chlamydia screening, but not about its benefits
Soldan K , Berman SM . Sex Transm Infect 2011 87 (2) 86-7 Andersen et al1 report findings from 9 years' follow-up in one county in Denmark of 30 000 men and women aged 21–23 years, of whom 9000 (4000 women and 5000 men) were randomly selected in 1997 to receive a mailed invitation to provide a self-obtained specimen for chlamydia screening. That study has exploited the rare opportunity offered by Danish health registers to link longitudinal health records for a cohort of young people, which included men (a rarity). Using an intention-to-treat analysis, the authors conclude that a single postal invite for chlamydia testing, with a repeat offer to those found positive, did not reduce the long-term risk of reproductive complications.1 What do these data add to the evidence base concerning the effectiveness of chlamydia screening? What lessons should inform further studies? | Previous randomised controlled trials (RCTs) of a single chlamydia screen, with 1-year follow-up for the incidence of pelvic inflammatory disease (PID), have noted the limitation of evaluating the impact of a single round of chlamydia screening, because the risk of chlamydia infection is ongoing,2 as should the intervention be.3 The study by Andersen et al1 with its long follow-up for ectopic pregnancy and infertility increases the probability of the acquisition of chlamydia infections after (or before) the intervention and accentuates this bias to a null finding for these outcomes. |
Maternal dengue and pregnancy outcomes: a systematic review
Pouliot SH , Xiong X , Harville E , Paz-Soldan V , Tomashek KM , Breart G , Buekens P . Obstet Gynecol Surv 2010 65 (2) 107-18 To assess the impact of dengue infection during pregnancy on birth outcomes, we conducted a systematic review of 30 published studies (19 case reports, 9 case series, and 2 comparison studies). Studies were identified by searching computerized databases using dengue and dengue hemorrhagic fever, cross-referenced with pregnancy, preterm birth or delivery, low birth weight, small-for-gestational age, spontaneous abortion, pre-eclampsia, eclampsia, or fetal death as search terms. The case reports examined showed high rates of cesarean deliveries (44.0%) and pre-eclampsia (12.0%) among women with dengue infection during pregnancy, while the case series showed elevated rates of preterm birth (16.1%) and cesarean delivery (20.4%). One comparative study found an increase in low birth weight among infants born to women with dengue infections during pregnancy, compared with infants born to noninfected women. Vertical transmission was described in 64.0% and 12.6% of women in case reports and case series (respectively), as well as in one comparative study. The authors conclude that there is a risk of vertical transmission, but whether maternal dengue infection is a significant risk factor for adverse pregnancy outcomes is inconclusive. More comparative studies are needed. TARGET AUDIENCE: Obstetricians & Gynecologists, Family Physicians. LEARNING OBJECTIVES: After completion of this educational activity, the participant should be better able to assess symptoms of dengue fever and locations where dengue fever occurs, describe possible perinatal complications of maternal dengue fever, and identify the limitations of available literature describing dengue fever in pregnancy. |
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