Publications by authors named "Natalya Kostandova"

The emergence of SARS-CoV-2 into a highly susceptible global population was primarily driven by human mobility-induced introduction events. Especially in the early stages, understanding mobility was vital to mitigating the pandemic prior to widespread vaccine availability. We conducted a systematic review of studies published from January 1, 2020, to May 9, 2021, that used population-level human mobility data to understand SARS-CoV-2 transmission.

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Background: Preventing COVID-19 in Gaza is crucial due to the devastation of advanced health services infrastructure by war. Despite the high protection offered by COVID-19 vaccines against severe disease, a 2021 survey in Gaza found only half of the population was vaccinated, and one-third was vaccine-hesitant. This follow-up study conducted in March 2023 aimed to re-evaluate vaccination levels, hesitancy, exposure to vaccine promotion efforts, and other risk factors in Gaza.

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Multiplex-based serological surveillance is a valuable but underutilized tool to understand gaps in population-level exposure, susceptibility, and immunity to infectious diseases. Assays for which blood samples can be tested for antibodies against several pathogens simultaneously, such as multiplex bead immunoassays, can more efficiently integrate public health surveillance in low- and middle-income countries. On March 7-8, 2023 a group of experts representing research institutions, multilateral organizations, private industry, and country partners met to discuss experiences, identify challenges and solutions, and create a community of practice for integrated, multi-pathogen serosurveillance using multiplex bead assay technologies.

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Introduction: Attacks on healthcare have further weakened the already fragile health system in the Central African Republic. We investigated attacks on healthcare in three conflict-affected prefectures-Ouaka, Haute-Kotto, and Vakaga-from 2016 to 2020. The study aim was to gain an in-depth understanding of the immediate and long-term effects of attacks on healthcare workers, facilities, supply chain, quality of care, and other components of the health system.

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Models of measles transmission can be used to identify areas of high risk to tailor immunization strategies. Estimates of spatial connectivity can be derived from data such as mobile phone records, however it is not clear how this maps to the movement of children who are more likely to be infected. Using travel surveys across two districts in Zambia and national mobile phone data, we compared estimates of out-of-district travel for the population captured in the mobile phone data and child-specific travel from travel surveys.

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Community-based serological studies are increasingly relied upon to measure disease burden, identify population immunity gaps, and guide control and elimination strategies; however, there is little understanding of the potential for and impact of sampling biases on outcomes of interest. As part of efforts to quantify measles immunity gaps in Zambia, a community-based serological survey using stratified multi-stage cluster sampling approach was conducted in Ndola and Choma districts in May-June 2022, enrolling 1245 individuals. We carried out a follow-up study among individuals missed from the sampling frame of the serosurvey in July-August 2022, enrolling 672 individuals.

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Article Synopsis
  • The study investigated the COVID-19 pandemic's impact on health services and community health-seeking behavior in the Mweso health zone of North Kivu, DRC, during its first year (March 2020-March 2021).
  • It employed a mixed-methods approach, including epidemiological analysis, health service usage data, and qualitative insights from health care workers and community members.
  • Findings indicated that, despite a rise in COVID-19 cases, health service utilization varied significantly, with financial limitations being cited as the primary barrier to accessing care, rather than direct impacts from COVID-19.
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To respond to the COVID-19 pandemic, countries introduced public health and social measures that had indirect societal, economic consequences. Concerns during epidemics include continuity of routine health services. We investigate how healthcare utilisation and healthcare seeking behaviour changed during the first year of the COVID-19 pandemic among host communities in Cox's Bazar, Bangladesh.

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The COVID-19 pandemic has impacted many facets of human behavior, including human mobility partially driven by the implementation of non-pharmaceutical interventions (NPIs) such as stay at home orders, travel restrictions, and workplace and school closures. Given the importance of human mobility in the transmission of SARS-CoV-2, there have been an increase in analyses of mobility data to understand the COVID-19 pandemic to date. However, despite an abundance of these analyses, few have focused on Sub-Saharan Africa (SSA).

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Background: Infection prevention and control (IPC) was a central component of the Democratic Republic of the Congo's COVID-19 response in 2020, aiming to prevent infections and ensure safe health service provision.

Objectives: We aimed to assess the evolution of IPC capacity in 65 health facilities supported by Action Contre la Faim in three health zones in Kinshasa (Binza Meteo (BM), Binza Ozone (BO), and Gombe), investigate how triage and alert validation were implemented, and estimate how health service utilisation changed in these facilities (April-December 2020).

Methods: We used three datasets: IPC Scorecard data assessing health facilities' IPC capacity at baseline, monthly and weekly triage data, and monthly routine data on eight health services.

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Article Synopsis
  • The study examined the impact of COVID-19 on health services and community health-seeking behavior in the Central African Republic (CAR), particularly in Bangui during the first year of the pandemic.
  • It utilized a mixed-methods approach, combining epidemiological analysis, health service utilization data, and qualitative insights from healthcare workers and community members.
  • Findings revealed a concentration of testing in urban areas, a decrease in health consultations across various services, and a notable fear of seeking care due to the pandemic's restrictions.
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Background: Measles-rubella supplementary immunization activities (MR-SIAs) are conducted to address inequalities in coverage and fill population immunity gaps when routine immunization services fail to reach all children with two doses of a measles-containing vaccine (MCV). We used data from a post-campaign coverage survey in Zambia to measure the proportion of measles zero-dose and under-immunized children who were reached by the 2020 MR-SIA and identified reasons associated with persistent inequalities following the MR-SIA.

Methods: Children between 9 and 59 months were enrolled in a nationally representative, cross-sectional, multistage stratified cluster survey in October 2021 to estimate vaccination coverage during the November 2020 MR-SIA.

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Article Synopsis
  • - The study explores how to effectively allocate convalescent plasma (CP) during the COVID-19 pandemic to minimize serious health issues and fatalities, using a simulation model to analyze different strategies.
  • - Results showed that giving CP priority to patients in early hospitalization significantly reduced deaths, averting about 15% more fatalities compared to only treating hospitalized individuals; prioritizing outpatients reduced hospitalizations by a notable 22%.
  • - The findings suggest that the best allocation strategy for CP depends on whether the goal is to reduce deaths, infections, or hospitalizations, with mixed allocation strategies yielding better overall outcomes than sticking to a single setting.
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Measles is a highly transmissible disease that requires high levels of vaccination coverage for control and elimination. Areas that are unable to achieve and maintain high coverage levels are at risk for measles outbreaks resulting in increased morbidity and mortality. Public health emergencies, such as the current COVID-19 pandemic, pose a threat to the functioning of health systems by disrupting immunization services which can derail measles vaccination efforts.

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  • The study investigates the impact of COVID-19 on refugee populations in Uganda, specifically analyzing case incidence and health service utilization during the first year of the pandemic.
  • It was found that initial COVID-19 incidence rates were lower among refugees compared to the general population, with lower testing capacity in refugee settlements.
  • Changes in health services showed that while consultations for acute conditions decreased, routine maternal and child health services were relatively less affected by the pandemic.
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Article Synopsis
  • The study investigated COVID-19 vaccination coverage and vaccine hesitancy among adults and healthcare workers in the Gaza Strip in October 2021, highlighting significant challenges due to the ongoing humanitarian crisis.
  • A total of 1,075 individuals were surveyed, revealing a 49% vaccination rate among the general population and a much higher rate of 89% among healthcare workers, with 34% of the overall population expressing vaccine hesitancy.
  • The analysis showed that factors such as being male, older age, higher education, and confidence in vaccine safety were positively associated with vaccination status, while similar factors contributed to vaccine hesitancy.
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Background: The effects of the Coronavirus Disease 2019 (COVID-19) pandemic in humanitarian contexts are not well understood. Specific vulnerabilities in such settings raised concerns about the ability to respond and maintain essential health services. This study describes the epidemiology of COVID-19 in Azraq and Zaatari refugee camps in Jordan (population: 37,932 and 79,034, respectively) and evaluates changes in routine health services during the COVID-19 pandemic.

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Background: The Transmission Assessment Survey (TAS) is a decision-making tool to determine when transmission of lymphatic filariasis is presumed to have reached a level low enough that it cannot be sustained even in the absence of mass drug administration. The survey is applied over geographic areas, called evaluation units (EUs); existing World Health Organization guidelines limit EU size to a population of no more than 2 million people.

Methodology/principal Findings: In 2015, TASs were conducted in 14 small EUs in Haiti.

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We observed micrometer-sized grains of wadsleyite, a high-pressure phase of (Mg,Fe)(2)SiO(4,) in the recovery products of a shock experiment. We infer these grains crystallized from shock-generated melt over a time interval of <1 micros, the maximum time over which our experiment reached and sustained pressure sufficient to stabilize this phase. This rapid crystal growth rate (approximately 1 m/s) suggests that, contrary to the conclusions of previous studies of the occurrence of high-pressure phases in shock-melt veins in strongly shocked meteorites, the growth of high-pressure phases from the melt during shock events is not diffusion-controlled.

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