The pitfalls of inferring virus–virus interactions from co-detection prevalence data: application to influenza and SARS-CoV-2

There is growing experimental evidence that many respiratory viruses—including influenza and SARS-CoV-2—can interact, such that their epidemiological dynamics may not be independent. To assess these interactions, standard statistical tests of independence suggest that the prevalence ratio—defined as the ratio of co-infection prevalence to the product of single-infection prevalences—should equal unity for non-interacting pathogens. As a result, earlier epidemiological studies aimed to estimate the prevalence ratio from co-detection prevalence data, under the assumption that deviations from unity implied interaction. To examine the validity of this assumption, we designed a simulation study that built on a broadly applicable epidemiological model of co-circulation of two emerging or seasonal respiratory viruses. By focusing on the pair influenza–SARS-CoV-2, we first demonstrate that the prevalence ratio systematically underestimates the strength of interaction, and can even misclassify antagonistic or synergistic interactions that persist after clearance of infection. In a global sensitivity analysis, we further identify properties of viral infection—such as a high reproduction number or a short infectious period—that blur the interaction inferred from the prevalence ratio. Altogether, our results suggest that ecological or epidemiological studies based on co-detection prevalence data provide a poor guide to assess interactions among respiratory viruses.

A comparative study of dengue virus vectors in major parks and adjacent residential areas in Ho Chi Minh City, Vietnam

The primary dengue virus vectors, Aedes aegypti and Aedes albopictus, are primarily daytime biting mosquitoes. The risk of infection is suspected to be considerable in urban parks due to visitor traffic. Despite the importance of vector control for reducing dengue transmission, little information is available on vector populations in urban parks. The present study characterized mosquito habitats and estimated vector densities in the major urban parks in Ho Chi Minh City, Vietnam and compared them with those in adjacent residential areas. The prevalences of habitats where Aedes larvae were found were 43% and 9% for the parks and residential areas, respectively. The difference was statistically significant (prevalence ratio [PR]: 5.00, 95% CI: 3.85–6.49). The prevalences of positive larval habitats were significantly greater in the parks for both species than the residential areas (PR: 1.52, 95% CI: 1.04–2.22 for A. aegypti, PR: 10.10, 95% CI: 7.23–14.12 for A. albopictus). Larvae of both species were positively associated with discarded containers and planters. Aedes albopictus larvae were negatively associated with indoor habitats, but positively associated with vegetation shade. The adult density of A. aegypti was significantly less in the parks compared with the residential areas (rate ratio [RR]; 0.09, 95% CI: 0.05–0.16), while the density of A. albopictus was significantly higher in the parks (RR: 9.99, 95% CI: 6.85–14.59). When the species were combined, the density was significantly higher in the parks (RR: 2.50, 95% CI: 1.92–3.25). The urban parks provide suitable environment for Aedes mosquitoes, and A. albopictus in particular. Virus vectors are abundant in the urban parks, and the current vector control programs need to have greater consideration of urban parks.

Legislative provisions for standardised tobacco packaging and changes in public support in 27 European countries

BackgroundGlobal adoption of standardised packaging requirements for tobacco products is a victory for public health, but their proliferation and impacts rely partly on public support. How this is related to legislation remains underassessed. This study explored change over time in public support for standardised packaging in countries with varying degrees of legislative provisions.MethodsWe used data from 27 European countries, collected from 2017 (n=28, 300) and 2020 (n=27, 901) waves of the Eurobarometer survey, to assess self-reported support for standardised packaging regulations among both smokers and non-smokers. Countries were grouped into three categories of policy adoption (policy implemented; policy legislated; no legislation) and changes in support were assessed using multilevel Poisson regression models.ResultsIn 2020, public support for standardised packaging was 71% (95% CI 68% to 74%) in countries that implemented standardised packaging legislation, 57% (55% to 60%) in countries that had legislated but not yet implemented legislation and 41% (40%to 42%) in countries with no legislation. Compared with 2017, this represented a relative change of +8% (1% to 15%), +12% (5% to 21%) and −5% (95% CI −2% to −8%), respectively, in the three country categories. Among smokers, there was no indication of change in support across the three groups. Among non-smokers, support increased in countries with existing legislation (adjusted prevalence ratio [aPR]=1.14, 95% CI 1.06 to 1.23) and decreased in countries with no legislation (aPR=0.93, 0.90 to 0.97).ConclusionsPublic support for standardised packaging regulations increased in countries implementing and legislating for these measures, particularly among non-smokers. An overall increase in support provides reassurance for policymakers defending policy action on tobacco packaging, as well as for those seeking to implement standardised packaging in their own countries.

The impact of a demand-side sanitation and hygiene promotion intervention on sustained behavior change and health in Amhara, Ethiopia: A cluster-randomized trial

Behaviors related to water, sanitation, and hygiene (WASH) are key drivers of infectious disease transmission, and experiences of WASH are potential influencers of mental well-being. Important knowledge gaps exist related to the content and delivery of effective WASH programs and their associated health impacts, particularly within the contexts of government programs implemented at scale. We developed and tested a demand-side intervention called Andilaye, which aimed to change behaviors related to sanitation, personal hygiene, and household environmental sanitation. This theory-informed intervention was delivered through the existing Ethiopian Health Extension Programme (HEP). It was a multilevel intervention with a catalyzing event at the community level and behavior change activities at group and household levels. We randomly selected and assigned 50 kebeles (sub-districts) from three woredas (districts), half to receive the Andilaye intervention, and half the standard of care sanitation and hygiene programming (i.e., community-led total sanitation and hygiene [CLTSH]). We collected data on WASH access, behavioral outcomes, and mental well-being. A total of 1,589 households were enrolled into the study at baseline; 1,472 households (94%) participated in an endline assessment two years after baseline, and approximately 14 months after the initiation of a multi-level intervention. The intervention did not improve construction of latrines (prevalence ratio [PR]: 0.99; 95% CI: 0.82, 1.21) or handwashing stations with water (PR: 0.96; 95% CI: 0.72, 1.26), or the removal of animal feces from the compound (PR: 1.10; 95% CI: 0.95, 1.28). Nor did it impact anxiety (PR: 0.90; 95% CI: 0.72, 1.11), depression (PR: 0.83; 95% CI: 0.64, 1.07), emotional distress (PR: 0.86; 95% CI: 0.67, 1.09) or well-being (PR: 0.90; 95% CI: 0.74, 1.10) scores. We report limited impact of the intervention, as delivered, on changes in behavior and mental well-being. The effectiveness of the intervention was limited by poor intervention fidelity. While sanitation and hygiene improvements have been documented in Ethiopia, behavioral slippage, or regression to unimproved practices, in communities previously declared open defecation free is widespread. Evidence from this trial may help address knowledge gaps related to challenges associated with scalable alternatives to CLTSH and inform sanitation and hygiene programming and policy in Ethiopia and beyond. Trial registration: This trial was registered with clinicaltrials.gov (NCT03075436) on March 9, 2017.

Prevalence of and factors associated with dental service utilization among early elderly in Lithuania

Background There is no recent information about dental service utilization (DSU) among elderly in Lithuania. We examined DSU and its associated factors in Lithuanian early elderly based on the Andersen’s behavioural model. Methods The cross-sectional study conducted in 2017–2019 included a nationally representative stratified sample of 370 Lithuanian early elderly aged 65–74 years (response rate of 54.5%). Information on predisposing factors (age, sex, nationality and education), enabling factor (residence), need-based factors (status of teeth, oral pain or discomfort, and dry mouth), general health, personal health practices and perceived stress was obtained from a structured, self-administered questionnaire. Clinically-assessed need-based factors included number of missing teeth and dental treatment need. Multivariable Poisson regression with robust variance estimates was used. Results A total of 239 study participants (64.6%) reported a dental visit during the last year and 338 (91.4%) needed dental treatments. A higher level of education (adjusted prevalence ratio [aPR] = 1.21, 95% confidence interval [CI]:1.04–1.40), pain or discomfort in teeth/mouth (aPR = 1.35, 95%CI: 1.13–1.62) and lower number of missing teeth (aPR = 0.99, 95%CI: 0.98–1.00) were associated with DSU. Conclusions Even though majority of early elderly needed dental treatments, only two-thirds visited a dentist during the last year. Predisposing and need-based factors were significant predictors of having a dental visit in the last year. A national oral health program for Lithuanian elderly with the focus on regular preventive dental check-ups is needed. More studies, both quantitative and qualitative, are warranted to investigate in depth the barriers for DSU among elderly in Lithuania.

Vitamin D Deficiency and Gestational Diabetes Mellitus in Relation to Body Mass Index

A relationship between vitamin D deficiency (VDD) and gestational diabetes mellitus (GDM) has been described. Considering that GDM prevalence depends on body mass index (BMI), our main objective was to determine if VDD is associated with GDM, independent of BMI. A cross-sectional study with 886 pregnant women was conducted in Elda (Spain) from September 2019 to June 2020. To assess the association, Poisson regression models with robust variance were used to estimate the prevalence ratio (PR). The observed GDM prevalence was 10.5%, while the VDD prevalence was 55.5%. In the crude model, both VDD and obesity were associated with GDM, but in the adjusted model, only VDD was statistically significant (PR = 1.635, p = 0.038). A secondary event analysis did not detect differences in VDD, but BMI yielded a higher frequency of births by cesarean section and newborns with a >90 percentile weight in the obesity group. In conclusion, VDD is associated with GDM, independent of BMI. Future longitudinal studies could provide information on causality.

Limitations in Activities of Daily Living in Individuals With Chronic Kidney Disease: Biopsychosocial Factors of the Brazilian Population

This study assesses the relationship between biopsychosocial factors and limitations in activities of daily living (ADL) in individuals with chronic kidney disease (CKD). Individual data from the National Health Survey were analyzed, with a sample size of 839 participants. The outcome was dichotomous, presenting limitations in ADL, and the factors considered were clinical and health characteristics, self-perceived behavior, contextual social support, and housing. Cox regression was applied to control the interaction between factors, using the prevalence ratio as a measure of effect and a significance level of 5%. A total of 839 individuals with CKD were reported, of which 373 (40.7%: 35.4 - 46.1%) reported having limitations in ADL. The presence of limitations in ADL was related to residing in a rural area, as well as to the absence of private health insurance, worse self-perceived health, presence of depressive symptoms, and disabilities, in addition to the use of medications and hemodialysis. Limitations in ADL in individuals with CKD are associated with biopsychosocial factors in the Brazilian population, requiring public policies that enable better therapeutic management and support for behavioral health and contextual needs.

The Association of Acculturative Stress with Self-reported Sleep Disturbance and Sleep Duration among Asian Americans

Study Objectives This study aims to examine associations between acculturative stress– defined as the psychological impact, or stress reaction, of adapting to a new cultural context –and self-reported sleep outcomes among Chinese and Korean immigrants in the United States. Methods In this cross-sectional study, acculturative stress was assessed using a 9-item scale, and sleep disturbance was measured using the 8-item scale. Sleep duration was self-reported. Poisson and linear regression analyses were conducted to examine the associations between acculturative stress, sleep disturbance, and sleep duration. Results Our sample consists of 400 participants (females: 52%, Chinese: 50%, Koreans: 50%, the mean of age=58.4). 81.8% of them were classified as having no sleep disturbance, while 18.2% were classified as having sleep disturbance. Poisson models revealed that greater acculturative stress was associated with a higher prevalence of sleep disturbance (Prevalence Ratio (PR): 1.18, 95% confidence interval (CI): 1.06-1.31). In linear models, a one-unit increase in acculturative stress was associated with 0.08 hours less sleep (p <0.05). Interaction tests indicated effect modification for sleep disturbance by sex and ethnic identity: only women had a significant association between acculturative stress and sleep disturbance (PR: 1.30; 95% CI: 1.13-1.49), while the association was significant for individuals identifying as “very Asian” (PR: 1.21; 95% CI: 1.08-1.35), but not for those identifying as “mostly Asian” or “bicultural/western”. Conclusions If findings are replicated, we suggest developing intervention programs for Asian immigrants to minimize acculturative stress and bolster protective factors that decrease the risk for poor sleep outcomes.