Project description:BackgroundEstimation of temporal changes in human immunodeficiency virus (HIV) transmission patterns can help to elucidate the impact of preventive strategies and public health policies.MethodsPortuguese HIV-1 subtype B and G pol genetic sequences were appended to global reference data sets to identify country-specific transmission clades. Bayesian birth-death models were used to estimate subtype-specific effective reproductive numbers (Re). Discrete trait analysis (DTA) was used to quantify mixing among transmission groups.ResultsWe identified 5 subtype B Portuguese clades (26-79 sequences) and a large monophyletic subtype G Portuguese clade (236 sequences). We estimated that major shifts in HIV-1 transmission occurred around 1999 (95% Bayesian credible interval [BCI], 1998-2000) and 2000 (95% BCI, 1998-2001) for subtypes B and G, respectively. For subtype B, Re dropped from 1.91 (95% BCI, 1.73-2.09) to 0.62 (95% BCI,.52-.72). For subtype G, Re decreased from 1.49 (95% BCI, 1.39-1.59) to 0.72 (95% BCI, .63-.8). The DTA suggests that people who inject drugs (PWID) and heterosexuals were the source of most (>80%) virus lineage transitions for subtypes G and B, respectively.ConclusionsThe estimated declines in Re coincide with the introduction of highly active antiretroviral therapy and the scale-up of harm reduction for PWID. Inferred transmission events across transmission groups emphasize the importance of prevention efforts for bridging populations.
Project description:BACKGROUND: Limited data exist on transmission dynamics and effectiveness of control measures for influenza in confined settings. OBJECTIVES: To investigate the transmission dynamics of a 2009 pandemic H1N1 influenza A outbreak aboard a Peruvian Navy ship and quantify the effectiveness of the implemented control measures. METHODS: We used surveillance data and a simple stochastic epidemic model to characterize and evaluate the effectiveness of control interventions implemented during an outbreak of 2009 pandemic H1N1 influenza A aboard a Peruvian Navy ship. RESULTS: The serological attack rate for the outbreak was 49·1%, with younger cadets and low-ranking officers at greater risk of infection than older, higher-ranking officers. Our transmission model yielded a good fit to the daily time series of new influenza cases by date of symptom onset. We estimated a reduction of 54·4% in the reproduction number during the period of intense control interventions. CONCLUSION: Our results indicate that the patient isolation strategy and other control measures put in place during the outbreak reduced the infectiousness of isolated individuals by 86·7%. Our findings support that early implementation of control interventions can limit the spread of influenza epidemics in confined settings.
Project description:ObjectivesTo characterize the impact of public health interventions on the volume and characteristics of admissions to the PICU.DesignMulticenter retrospective cohort study.SettingSix U.S. referral PICUs during February 15, 2020-May 14, 2020, compared with the same months during 2017-2019 (baseline).PatientsPICU admissions excluding admissions for illnesses due to severe acute respiratory syndrome coronavirus 2 and readmissions during the same hospitalization.InterventionsNone.Measurements and main resultsPrimary outcome was admission volumes during the period of stay-at-home orders (March 15, 2020-May 14, 2020) compared with baseline. Secondary outcomes were hospitalization characteristics including advanced support (e.g., invasive mechanical ventilation), PICU and hospital lengths of stay, and mortality. We used generalized linear mixed modeling to compare patient and admission characteristics during the stay-at-home orders period to baseline. We evaluated 7,960 admissions including 1,327 during March 15, 2020-May 14, 2020. Daily admissions and patients days were lower during the period of stay-at-home orders compared with baseline: median admissions 21 (interquartile range, 17-25) versus 36 (interquartile range, 30-42) (p < 0.001) and median patient days 93.0 (interquartile range, 55.9-136.7) versus 143.6 (interquartile range, 108.5-189.2) (p < 0.001). Admissions during the period of stay-at-home orders were less common in young children and for respiratory and infectious illnesses and more common for poisonings, endocrinopathies and for children with race/ethnicity categorized as other/unspecified. There were no differences in hospitalization characteristics except fewer patients received noninvasive ventilation during the period of stay-at-home orders.ConclusionsReductions in PICU admissions suggest that much of pediatric critical illness in younger children and for respiratory and infectious illnesses may be preventable through targeted public health strategies.
Project description:In this article, we statistically examine the effectiveness of non-pharmaceutical interventions (NPIs) implemented by the national governments of Greece and Cyprus during 2020 to (a) limit the spread of the SARS-CoV-2 virus, and (b) mitigate the economic fallout brought about by the Covid-19 pandemic. Applying a modified health belief model, we hypothesize that behavioral outcomes at the policy level are a function of NPIs, perceived severity, and social context. We employ a Prais-Winsten estimation in 2-week averages and report panel-corrected standard errors to find that NPIs have clear, yet differential, effects on public health and the economy in terms of statistical significance and time lags. The study provides a critical framework to inform future interventions during emerging pandemics.
Project description:Disease tolerance is a defense strategy against infections that aims at maintaining host health even at high pathogen replication or load. Tolerance mechanisms are currently intensively studied with the long-term goal of exploiting them therapeutically. Because tolerance-based treatment imposes less selective pressure on the pathogen it has been hypothesised to be "evolution-proof". However, the primary public health goal is to reduce the incidence and mortality associated with a disease. From this perspective, tolerance-based treatment bears the risk of increasing the prevalence of the disease, which may lead to increased mortality. We assessed the promise of tolerance-based treatment strategies using mathematical models. Conventional treatment was implemented as an increased recovery rate, while tolerance-based treatment was assumed to reduce the disease-related mortality of infected hosts without affecting recovery. We investigated the endemic phase of two types of infections: acute and chronic. Additionally, we considered the effect of pathogen resistance against conventional treatment. We show that, for low coverage of tolerance-based treatment, chronic infections can cause even more deaths than without treatment. Overall, we found that conventional treatment always outperforms tolerance-based treatment, even when we allow the emergence of pathogen resistance. Our results cast doubt on the potential benefit of tolerance-based over conventional treatment. Any clinical application of tolerance-based treatment of infectious diseases has to consider the associated detrimental epidemiological feedback.
Project description:IntroductionThe 10-valent pneumococcal conjugate vaccine (PCV10, Synflorix) was introduced into the Dutch pediatric national immunization program (NIP) starting in 2011. However, there is substantial pneumococcal disease burden due to increases in non-PCV10 covered serotypes. Higher-valent vaccines for pediatrics (PCV13, PCV15, and PCV20) may alleviate much of the remaining disease burden upon implementation through broader serotype coverage. This article assesses the public health impact of different pediatric vaccination strategies (switching to PCV13, PCV15 or PCV20) versus maintaining PCV10 at different time intervals in the Netherlands.MethodsA population-based, decision-analytic model was developed using historical pneumococcal disease surveillance data to forecast future invasive pneumococcal disease (IPD), pneumonia, and otitis media (OM) cases over a 7-year period (2023-2029) under the following strategies: continued use of PCV10, switching to PCV13 in 2023, switching to PCV15 in 2023, and switching to PCV20 in 2024. Scenario analyses were performed to account for uncertainties in future serotype distributions, disease incidence reductions, and epidemiologic parameters.ResultsSwitching to PCV13 in 2023 was found to avert 26,666 cases of pneumococcal disease compared to continuing PCV10 over a 7-year period (2023-2029). Switching to PCV15 in 2023 was found to avert 30,645 pneumococcal cases over the same period. Switching to PCV20 once available in 2024 was estimated to avert 45,127 pneumococcal cases from 2024-2029. Overall conclusions were maintained after testing uncertainties.ConclusionsFor the Dutch pediatric NIP, switching to PCV13 in 2023 would be an effective strategy compared with continued use of PCV10 for averting pneumococcal disease cases. Switching to PCV20 in 2024 was estimated to avert the most pneumococcal disease cases and provide the highest protection. However, in the face of budget constraints and the undervaluation of prevention strategies, it remains challenging to implement higher valent vaccines. Further research is needed to understand the cost-effectiveness and feasibility of a sequential approach.
Project description:BackgroundThe outbreak of highly pathogenic H5N1 influenza in domestic poultry and wild birds has caused global concern over the possible evolution of a novel human strain [1]. If such a strain emerges, and is not controlled at source [2,3], a pandemic is likely to result. Health policy in most countries will then be focused on reducing morbidity and mortality.Methods and findingsWe estimate the expected reduction in primary attack rates for different household-based interventions using a mathematical model of influenza transmission within and between households. We show that, for lower transmissibility strains [2,4], the combination of household-based quarantine, isolation of cases outside the household, and targeted prophylactic use of anti-virals will be highly effective and likely feasible across a range of plausible transmission scenarios. For example, for a basic reproductive number (the average number of people infected by a typically infectious individual in an otherwise susceptible population) of 1.8, assuming only 50% compliance, this combination could reduce the infection (symptomatic) attack rate from 74% (49%) to 40% (27%), requiring peak quarantine and isolation levels of 6.2% and 0.8% of the population, respectively, and an overall anti-viral stockpile of 3.9 doses per member of the population. Although contact tracing may be additionally effective, the resources required make it impractical in most scenarios.ConclusionsNational influenza pandemic preparedness plans currently focus on reducing the impact associated with a constant attack rate, rather than on reducing transmission. Our findings suggest that the additional benefits and resource requirements of household-based interventions in reducing average levels of transmission should also be considered, even when expected levels of compliance are only moderate.
Project description:This study characterized COVID-19 transmission in Ghana in 2020 and 2021 by estimating the time-varying reproduction number (Rt) and exploring its association with various public health interventions at the national and regional levels. Ghana experienced four pandemic waves, with epidemic peaks in July 2020 and January, August, and December 2021. The epidemic peak was the highest nationwide in December 2021 with Rt ≥ 2. Throughout 2020 and 2021, per-capita cumulative case count by region increased with population size. Mobility data suggested a negative correlation between Rt and staying home during the first 90 days of the pandemic. The relaxation of movement restrictions and religious gatherings was not associated with increased Rt in the regions with fewer case burdens. Rt decreased from > 1 when schools reopened in January 2021 to < 1 after vaccination rollout in March 2021. Findings indicated most public health interventions were associated with Rt reduction at the national and regional levels.
Project description:To assess the conduct of delivery of public health services at the municipal level in Denmark by applying services enlisted in the Essential Public Health Operation framework (EPHO) of WHO. We conducted individual qualitative interviews with key informants working with public health using a self-assessment survey tool in order to obtain an in-depth understanding of the interrelation or multidisciplinary work in Kolding Municipality. The developed self-assessment survey tool entailed questions about essential public health activities performed in a municipality. The Municipality organizes and contributes to core service delivery EPHOs, namely health protection, health promotion, and disease prevention. It collaborates with the general practitioners and the Region of Southern Denmark, responsible for hospital care, to fulfill the selected EPHOs. To obtain a comprehensive picture of the organizations that deliver public health services within a municipality, it is necessary to conduct interviews with representatives from those organizations as well. Additionally, the results from this study can be used to improve the survey tool further and hereafter conduct a nationwide survey in Denmark, as well as other European countries.
Project description:IntroductionEconomic evaluation has an important role to play in the demonstration of value for money of early childhood public health interventions; however, concerns have been raised regarding their consistent application and relevance to commissioners. This systematic review of the literature therefore aims to collate the breadth of the existing economic evaluation evidence of these interventions and to identify the approaches adopted in the assessment of value.Source of dataRecently published literature in Medline, EMBASE, EconLit, Health Management Information Consortium, Cochrane CENTRAL, Cochrane Database of Systematic Reviews, Health Technology Assessment, NHS EED and Web of Science.Areas of agreementThe importance of the early childhood period on future health and well-being as well as the potential to impact health inequalities making for a strong narrative case for expenditure in early childhood public health.Areas of controversyThe most appropriate approaches to evaluating value for money of such preventative interventions relevant for UK decision-makers given the evident challenges.Growing pointsThe presented review considered inconsistencies across methodological approaches used to demonstrate value for money. The results showed a mixed picture in terms of demonstrating value for money.Areas timely for developing researchFuture resource allocations decisions regarding early childhood public health interventions may benefit from consistency in the evaluative frameworks and health outcomes captured, as well as consistency in approaches to incorporating non-health costs and outcomes, incorporating equity concerns and the use of appropriate time horizons.