RESUMO

Estimating an infectious disease attack rate requires inference on the number of reported symptomatic cases of a disease, the number of unreported symptomatic cases, and the number of asymptomatic infections. Population-level immunity can then be estimated as the attack rate plus the number of vaccine recipients who had not been previously infected; this requires an estimate of the fraction of vaccines that were distributed to seropositive individuals. To estimate attack rates and population immunity in southern New England, we fit a validated dynamic epidemiological model to case, clinical, and death data streams reported by Rhode Island, Massachusetts, and Connecticut for the first 15 months of the COVID-19 pandemic, from March 1 2020 to May 31 2021. This period includes the initial spring 2020 wave, the major winter wave of 2020-2021, and the lagging wave of lineage B.1.1.7(Alpha) infections during March-April 2021. In autumn 2020, SARS-CoV-2 population immunity (equal to the attack rate at that point) in southern New England was still below 15%, setting the stage for a large winter wave. After the roll-out of vaccines in early 2021, population immunity in many states was expected to approach 70% by spring 2021, with more than half of this immune population coming from vaccinations. Our population immunity estimates for May 31 2021 are 73.4% (95% CrI: 72.9% - 74.1%) for Rhode Island, 64.1% (95% CrI: 64.0% - 64.4%) for Connecticut, and 66.3% (95% CrI: 65.9% - 66.9%) for Massachusetts, indicating that >33% of southern Englanders were still susceptible to infection when the Delta variant began spreading in July 2021. Despite high vaccine coverage in these states, population immunity in summer 2021 was lower than planned due to 34% (Rhode Island), 25% (Connecticut), and 28% (Massachusetts) of vaccine distribution going to seropositive individuals. Future emergency-setting vaccination planning will likely have to consider over-vaccination as a strategy to ensure that high levels of population immunity are reached during the course of an ongoing epidemic.

RESUMO

In the United States, state-level re-openings in spring 2020 presented an opportunity for the resurgence of SARS-CoV-2 transmission. One important question during this time was whether human contact and mixing patterns could increase gradually without increasing viral transmission, the rationale being that new mixing patterns would likely be associated with improved distancing, masking, and hygiene practices. A second key question to follow during this time was whether clinical characteristics of the epidemic would improve after the initial surge of cases. Here, we analyze age-structured case, hospitalization, and death time series from three states - Rhode Island, Massachusetts, and Pennsylvania - that had successful re-openings in May 2020 without summer waves of infection. Using a Bayesian inference framework on eleven daily data streams and flexible daily population contact parameters, we show that population-average mixing rates dropped by >50% during the lockdown period in March/April, and that the correlation between overall population mobility and transmission-capable mobility was broken in May as these states partially re-opened. We estimate the reporting rates (fraction of symptomatic cases reporting to health system) at 96.0% (RI), 72.1% (MA), and 75.5% (PA); in Rhode Island, when accounting for cases caught through general-population screening programs, the reporting rate estimate is 94.5%. We show that elderly individuals were less able to reduce contacts during the lockdown period when compared to younger individuals. Attack rate estimates through August 31 2020 are 6.4% (95% CI: 5.8% ‒ 7.3%) of the total population infected for Rhode Island, 5.7% (95% CI: 5.0% ‒ 6.8%) in Massachusetts, and 3.7% (95% CI: 3.1% ‒ 4.5%) in Pennsylvania, with some validation available through published seroprevalence studies. Infection fatality rates (IFR) estimates for the spring epidemic are higher in our analysis (>2%) than previously reported values, likely resulting from the epidemics in these three states affecting the most vulnerable sub-populations, especially the most vulnerable of the ≥80 age group.

RESUMO

As three SARS-CoV-2 vaccines come to market in Europe and North America in the winter of 2020-2021, distribution networks will be in a race against a major epidemiological wave of SARS-CoV-2 that began in autumn 2020. Rapid and optimized vaccine allocation is critical during this time. With 95% efficacy reported for two of the vaccines, near-term public health needs require that distribution is prioritized to the elderly, health-care workers, teachers, essential workers, and individuals with co-morbidities putting them at risk of severe clinical progression. Here, we evaluate various age-based vaccine distributions using a validated mathematical model based on current epidemic trends in Rhode Island and Massachusetts. We allow for varying waning efficacy of vaccine-induced immunity, as this has not yet been measured. We account for the fact that known COVID-positive cases may not be included in the first round of vaccination. And, we account for current age-specific immune patterns in both states. We find that allocating a substantial proportion ( > 75%) of vaccine supply to individuals over the age of 70 is optimal in terms of reducing total cumulative deaths through mid-2021. As we do not explicitly model other high mortality groups, this result on vaccine allocation applies to all groups at high risk of mortality if infected. Our analysis confirms that for an easily transmissible respiratory virus, allocating a large majority of vaccinations to groups with the highest mortality risk is optimal. Our analysis assumes that health systems during winter 2020-2021 have equal staffing and capacity to previous phases of the SARS-CoV-2 epidemic; we do not consider the effects of understaffed hospitals or unvaccinated medical staff. Vaccinating only seronegative individuals avoids redundancy in vaccine use on individuals that may already be immune, and will result in 1% to 2% reductions in cumulative hospitalizations and deaths by mid-2021. Assuming high vaccination coverage ( > 28%) and no major relaxations in distancing, masking, gathering size, or hygiene guidelines between now and spring 2021, our model predicts that a combination of vaccination and population immunity will lead to low or near-zero transmission levels by the second quarter of 2021.

RESUMO

Using nation-wide survey data (N=2328) from China, this study investigates how social support from family, peers, and teachers influence low-income household children's (from 13 to 15 years old) academic resilience, as well as how academic resilience mediates the relationship between social support and children's academic achievement. Structural equation modelling was adopted to analyse the data. The results reveal that (1) low-income household children's family, peer, and teacher support are associated with their academic resilience; (2) peer support and academic resilience of low-income household children significantly relate with their academic achievements; (3) academic resilience plays a full mediation role in teacher support and a partial mediation role in peer support on children's academic achievement. The implications of this study on theory and practice, the limitations, and future research directions are discussed.

Utilizando datos de encuestas a nivel nacional (N = 2328) de China, este estudio investiga cómo el apoyo social de la familia, los compañeros y los maestros influyen en la resiliencia académica de los niños de bajos ingresos (de 13 a 15 años), así como la resiliencia académica interviene en la relación entre el apoyo social y el rendimiento académico de los niños. Se adoptó el modelo de ecuaciones estructurales para analizar los datos. Los resultados revelan que (1) el apoyo familiar, de pares y de maestros de niños de bajos ingresos en el hogar está asociado con su capacidad de resilencia académica; (2) el apoyo entre pares y la resilencia académica de los niños de hogares de bajos ingresos se relacionan significativamente con sus logros académicos; (3) la capacidad de resilencia académica desempeña un papel de mediación total en el apoyo del maestro y un papel de mediación parcial en el apoyo de los compañeros en el rendimiento académico de los niños. Se discuten las implicaciones de este estudio en la teoría y la práctica, además de las limitaciones y las futuras direcciones de investigación.

RESUMO

BACKGROUND: The Dominican Republic (DR) ranks among nations with the highest burden of HIV in the Caribbean. Cultural and gender roles in rural areas of the DR may place women at increased HIV risk. However, little is known about sexual health and HIV testing behaviors among women in the rural DR. METHODS: We conducted a needs assessment among a systematic sample of adult women in a rural DR community in 2016. Demographic and behavioral attributes related to HIV testing, sexual health, and healthcare utilization were evaluated. Poisson regression analysis was used to identify demographics and behaviors associated with having had a previous HIV test. Significance was defined as a p-value < 0.05. RESULTS: Among 105 women evaluated, 77% knew someone with HIV and 73% of women reported that they would be very or extremely likely to take an HIV test if offered. Only 68% reported a previous HIV test, including 47% who were tested over 2 years prior. Barriers to HIV testing included low risk perception (23%), distance or requisite travel (13%), and discomfort being tested (11%). Women who had never been tested for HIV were more likely than those who had been tested to be older (p = 0.03), to have a lower level of education (p = 0.04), and to have never been tested for other sexually transmitted infections (STI; p <  0.01). In the Poisson multiple regression model, the only significant predictor of having had an HIV test was having had an STI test (p = 0.03). CONCLUSIONS: In the rural DR, numerous barriers contribute to low prevalence of HIV testing among women. Most women report willingness to have an HIV test and many engage in routine health care, indicating that this population may benefit from incorporating HIV testing and other sexual health promotion activities into routine medical care.

Assuntos

RESUMO

Few studies evaluate knowledge and willingness to use pre-exposure prophylaxis (PrEP) among men who have sex with men (MSM) in middle-income countries. Brazil added PrEP to public drug formularies in December 2017, but little is known about local knowledge and attitudes about PrEP among MSM outside metropolitan areas in Southern Brazil. The cross-sectional HIV Surveillance Survey Project in Brazil estimates HIV and STD prevalence among MSM in 12 state capitals. Among 32 participants at the Salvador, Bahia study site, we used qualitative interviews to assess knowledge, willingness, and barriers to PrEP use among MSM; few MSM had previous knowledge of PrEP and were willing to use PrEP. Clinical, behavioural, social, and structural factors influencing participants' knowledge and willingness to take PrEP included concerns about efficacy and side effects, access to culturally congruent services for MSM, and stigma. Some participants reported that learning about PrEP online positively influenced their willingness to use PrEP. Participants' opinions about PrEP's contribution to risk compensation varied. Interventions to provide culturally congruent care and destigmatise PrEP for MSM at high risk for HIV acquisition, particularly those conducted collaboratively with Brazil's civil society movement, may enhance the public health effort to expand access to PrEP in Brazil.

Assuntos

RESUMO

INTRODUCTION: HIV continues to be a major health concern with approximately 2.1 million new infections occurring worldwide in 2015. In Central America, Guatemala had the highest incident number of HIV infections (3,700) in 2015. Antiretroviral pre-exposure prophylaxis (PrEP) was recently recommended by the World Health Organization (WHO) as an efficacious intervention to prevent HIV transmission. PrEP implementation efforts are underway in Guatemala and success will require providers that are knowledgeable and willing to prescribe PrEP. We sought to explore current PrEP awareness and prescribing attitudes among Guatemalan physicians in order to inform future PrEP implementation efforts. METHODS: We conducted a cross-sectional survey of adult internal medicine physicians at the main teaching hospital in Guatemala City in March 2015. The survey included demographics, medical specialty, years of HIV patient care, PrEP awareness, willingness to prescribe PrEP, previous experience with post-exposure prophylaxis, and concerns about PrEP. The primary outcome was willingness to prescribe PrEP, which was assessed using a 5-point Likert scale for different at-risk population scenarios. Univariate and multivariate logistic regression was performed to identify predictors for willingness to prescribe PrEP. RESULTS: Eighty-seven physicians completed the survey; 66% were male, 64% were internal medicine residency trainees, and 10% were infectious disease (ID) specialists. Sixty-nine percent of physicians were PrEP aware, of which 9% had previously prescribed PrEP. Most (87%) of respondents were willing to prescribe PrEP to men who have sex with men (MSM), sex workers, injection drug users, or HIV-uninfected persons having known HIV-positive sexual partners. Concerns regarding PrEP included development of resistance (92%), risk compensation (90%), and cost (64%). Univariate logistic regression showed that younger age, being a resident trainee, and being a non-ID specialist were significant predictors for willingness to prescribe PrEP. In multivariate logistic regression, being a non-ID specialist was a significant predictor. CONCLUSIONS: Guatemalan physicians at an urban public hospital were PrEP aware and willing to prescribe, but few have actually done so yet. Future education programs should address the concerns identified, including the low potential for the development of antiretroviral resistance. These findings can aid PrEP implementation efforts in Guatemala.

Assuntos