Molecular Characterization of the Convergent Carbapenem-Resistant and Hypervirulent Klebsiella pneumoniae Strain K1-ST23, Collected in Chile during the COVID-19 Pandemic.

The aim of this study was to investigate the genomic features of a carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKp) isolate (K-2157) collected in Chile. Antibiotic susceptibility was determined using the disk diffusion and broth microdilution methods. Whole-genome sequencing (WGS) and hybrid assembly were performed, using data generated on the Illumina and Nanopore platforms. The mucoid phenotype was analyzed using both the string test and sedimentation profile. The genomic features of K-2157 (e.g., sequence type, K locus, and mobile genetic elements) were retrieved using different bioinformatic tools. Strain K-2157 exhibited resistance to carbapenems and was identified as a high-risk virulent clone belonging to capsular serotype K1 and sequence type 23 (ST23). Strikingly, K-2157 displayed a resistome composed of ß-lactam resistance genes (blaSHV-190, blaTEM-1, blaOXA-9, and blaKPC-2), the fosfomycin resistance gene fosA, and the fluoroquinolones resistance genes oqxA and oqxB. Moreover, several genes involved in siderophore biosynthesis (ybt, iro, and iuc), bacteriocins (clb), and capsule hyperproduction (plasmid-borne rmpA [prmpA] and prmpA2) were found, which is congruent with the positive string test displayed by K-2157. In addition, K-2157 harbored two plasmids: one of 113,644 bp (KPC+) and another of 230,602 bp, containing virulence genes, in addition to an integrative and conjugative element (ICE) embedded on its chromosome, revealing that the presence of these mobile genetic elements mediates the convergence between virulence and antibiotic resistance. Our report is the first genomic characterization of a hypervirulent and highly resistant K. pneumoniae isolate in Chile, which was collected during the coronavirus disease 2019 (COVID-19) pandemic. Due to their global dissemination and public health impact, genomic surveillance of the spread of convergent high-risk K1-ST23 K. pneumoniae clones should be highly prioritized. IMPORTANCE Klebsiella pneumoniae is a resistant pathogen involved primarily in hospital-acquired infections. This pathogen is characterized by its notorious resistance to last-line antibiotics, such as carbapenems. Moreover, hypervirulent K. pneumoniae (hvKp) isolates, first identified in Southeast Asia, have emerged globally and are able to cause infections in healthy people. Alarmingly, isolates displaying a convergence phenotype of carbapenem resistance and hypervirulence have been detected in several countries, representing a serious threat to public health. In this work, we analyzed the genomic characteristics of a carbapenem-resistant hvKp isolate recovered in 2022 from a patient with COVID-19 in Chile, representing the first analysis of this type in the country. Our results will provide a baseline for the study of these isolates in Chile, which will support the adoption of local measures aimed at controlling their dissemination.

[Impact of mitigation measures on the COVID-19 pandemic in Chile: preliminary data for the period April 14 to May 14]. / Impacto de diferentes medidas de mitigación en el curso de la pandemia de COVID-19 en Chile: proyección preliminar para el período del 14 de abril al 14 de mayo.

OBJETIVE: To model disease progression, healthcare demand and case fatality rate attributed to COVID-19 pandemic that may occur in Chile in 1-month time, by simulating different scenarios according to diverse mitigation measures hypothetically implemented. Furthermore, we aimed to estimate the same outcomes assuming that 70% of the population will be infected by SARS-CoV-2, with no time limit assumption. METHODS: We based on the number of confirmed COVID-19 cases in Chile up to April 14th 2020 (8 273 cases and 94 deaths). For the simulated scenarios we assumed basic reproduction numbers ranging from R0=2.5 to R0=1.5. The estimation of the number of patients that would require intensive care and the age-specific case fatality rate were based on data provided by the Imperial College of London and the Instituto Superiore di Sanità en Italia. RESULTS: If no mitigation measures were applied (R0=2.5), by May 25, Chile would have 2 019 775 cases and 15 068 deaths. If mitigations measures were implemented to decrease R0 to 1.5 (early detection of cases, quarantine, social distancing of elderly), the number of cases and deaths would importantly decrease. Nonetheless, the demand for in-hospital care including intensive care would exceed the available resources. Our age-specific analysis showed that population over 60 years are at higher risk of needing intensive care and death. CONCLUSION: Our evidence supports the mitigation measures implemented by the Chilean government. Nevertheless, more stringent measures are needed to prevent the health care system's collapse due to shortfall of resources to confront the COVID-19 pandemic.

[COVID-19 risk groups and their strategies for navigating information overload during the first year of the pandemic in Chile]. / Grupos de riesgo por COVID-19 y sus estrategias para enfrentar la sobrecarga informativa en el primer año de la pandemia en Chile.

As a part of the EIS-COVID project on the access and use of information during the COVID-19 pandemic in Chile, the objective of this paper was to ascertain how people's informational environment was constructed during the first stage of the pandemic. It discusses the results of a qualitative study of people belonging to risk groups for COVID-19: people over 18 and under 65 with chronic diseases (hypertension and diabetes) and people 65 and over. Ninety semi-structured interviews were conducted in the Metropolitan and Valparaíso regions between September 2020 and January 2021. The results reveal the problematic nature of the information overload encountered by these groups and the strategies they used to navigate it: a) information avoidance; b) content corroboration and active search for reliable sources; and c) differentiated media use.

Este artículo se enmarca en el proyecto EIS-COVID sobre acceso y uso de información en el contexto de la pandemia de COVID-19 en Chile. Su objetivo fue conocer cómo se constituyó el entorno informativo de las personas en la primera etapa de la pandemia. El artículo muestra los resultados de un estudio cualitativo enfocado en personas pertenecientes a grupos de riesgo por COVID-19: personas mayores de 18 y menores de 65 años con enfermedades crónicas (hipertensión y diabetes) y personas de 65 años y más. Se realizaron 90 entrevistas semiestructuradas en las regiones Metropolitana y de Valparaíso entre septiembre de 2020 y enero de 2021. Se identifica la problemática de la sobrecarga informativa para estos grupos y las estrategias que utilizaron para enfrentarla: a) la evitación de información, b) la corroboración de contenidos y búsqueda activa de fuentes confiables, o c) el uso diferenciado de medios.

Population well-being and the COVID-19 vaccination program in Chile: evidence from Google Trends.

OBJECTIVE: We analyze the dynamics of the mental well-being of the Chilean population in response to the progress of the vaccination strategy implemented by the government. STUDY DESIGN: This study aims at investigating the possibility of using Google Trends as an instrument for tracking mental well-being of the Chilean population. METHODS: We use the volume of searches for keywords in Google Trends (GT) related to Anguish, Anxiety, Depression, and Stress as a proxy for population well-being. Using event study methods, we analyze social attention reactions to news about the vaccination program. We implement a Difference-in-Difference-in-Differences estimation to estimate changes in population welfare by socio-economic status induced by the progress of inoculation. RESULTS: We show that social attention to mental health problems is sensitive to news about the vaccination program. Moreover, and most importantly, we find that mental well-being responds positively to the percentage of inoculated people. This phenomenon appear to be permanent and affected by socio-economic status, with the wealthier population experiencing greater improvements than the less wealthy. CONCLUSIONS: During the COVID-19 vaccination program in Chile, social attention to mental health problems appears to be sensitive to news about the vaccination program. There is also strong evidence of socio-economic status-induced heterogeneity in population responses to program implementation. The above phenomena appears to be permanent and cannot be attributed to either socio-economic segregation in access to vaccines or to the highly stratified schedule of the vaccination program.

A general modeling framework for quantitative tracking, accurate prediction of ICU, and assessing vaccination for COVID-19 in Chile.

Background: One of the main lessons of the COVID-19 pandemic is that we must prepare to face another pandemic like it. Consequently, this article aims to develop a general framework consisting of epidemiological modeling and a practical identifiability approach to assess combined vaccination and non-pharmaceutical intervention (NPI) strategies for the dynamics of any transmissible disease. Materials and methods: Epidemiological modeling of the present work relies on delay differential equations describing time variation and transitions between suitable compartments. The practical identifiability approach relies on parameter optimization, a parametric bootstrap technique, and data processing. We implemented a careful parameter optimization algorithm by searching for suitable initialization according to each processed dataset. In addition, we implemented a parametric bootstrap technique to accurately predict the ICU curve trend in the medium term and assess vaccination. Results: We show the framework's calibration capabilities for several processed COVID-19 datasets of different regions of Chile. We found a unique range of parameters that works well for every dataset and provides overall numerical stability and convergence for parameter optimization. Consequently, the framework produces outstanding results concerning quantitative tracking of COVID-19 dynamics. In addition, it allows us to accurately predict the ICU curve trend in the medium term and assess vaccination. Finally, it is reproducible since we provide open-source codes that consider parameter initialization standardized for every dataset. Conclusion: This work attempts to implement a holistic and general modeling framework for quantitative tracking of the dynamics of any transmissible disease, focusing on accurately predicting the ICU curve trend in the medium term and assessing vaccination. The scientific community could adapt it to evaluate the impact of combined vaccination and NPIs strategies for COVID-19 or any transmissible disease in any country and help visualize the potential effects of implemented plans by policymakers. In future work, we want to improve the computational cost of the parametric bootstrap technique or use another more efficient technique. The aim would be to reconstruct epidemiological curves to predict the combined NPIs and vaccination policies' impact on the ICU curve trend in real-time, providing scientific evidence to help anticipate policymakers' decisions.

Infection with SARS-CoV-2 variant Gamma (P.1) in Chile increased ICU admission risk three to five-fold.

The 2021 wave of SARS-CoV-2 infection in Chile was characterized by an explosive increase in ICU admissions, which disproportionately affected individuals younger than 60 years. This second wave was also accompanied by an explosive increase in Gamma (P.1) variant detections and the massive vaccine rollout. We unveil the role the Gamma variant played in stressing the use of critical care, by developing and calibrating a queueing model that uses data on new onset cases and actual ICU occupancy, symptom's onset to ICU admission interval, ICU length-of-stay, genomic surveillance, and vaccine effectiveness. Our model shows that infection with the Gamma (P.1) variant led to a 3.5-4.7-fold increase in ICU admission for people younger than 60 years. This situation occurred on top of the already reported higher infection rate of the Gamma variant. Importantly, our results also strongly suggest that the vaccines used in Chile (inactivated mostly, but also an mRNA), were able to curb Gamma variant ICU admission over infections.

Mental health care before and during the COVID-19 pandemic in public healthcare centers of a Chilean municipality. / Atención de salud mental antes y durante la pandemia COVID-19 en centros de salud pública de una municipalidad de Chile.

Introduction: Globally, the COVID-19 pandemic has affected people's mental health care. This study aims to describe mental health care in the first semester of the COVID-19 pandemic of the year 2020 compared to the first semester of the year 2019 in the public health establishments of the commune of Chillán, Chile. Methods: A descriptive ecological study. The treated cases were analyzed in aggregate, considering the pandemic, amount of admissions, the reason for consultation, sex, and age for the years 2019 and 2020. Prevalence, percentages, and statistical analysis were evaluated using non-parametric tests. Results: The prevalence of cases due to admissions to the mental health program in primary health care remained similar between the first semester of 2019 and the first semester of 2020. Most mental health cases concentrate on mood (affective) and anxiety disorders. Statistically significant differences were observed between 2019 and 2020 in the number of mental health admissions for mental and behavioral disorders due to psychotropic substances, harmful use disorders, drug dependence, and personality disorders. Conclusions: It is a priority for Chile to increase coverage in primary mental health care. The data provided in this study show at an exploratory level that the initial situation of the pandemic could have affected access to timely care for the most vulnerable people with mental disorders.

Introducción: A nivel mundial, la pandemia por COVID-19 ha afectado la atención en salud mental de las personas. El presente estudio tiene como propósito describir la atención de salud mental en el primer semestre de la pandemia COVID-19 del año 2020, comparado con el primer semestre del año 2019 en los establecimientos de salud pública de la comuna de Chillán, Chile. Métodos: Estudio ecológico descriptivo. Se analizaron de manera agregada los casos atendidos considerando la pandemia, cantidad de ingresos, motivo de consulta, sexo y edad para los años 2019 y 2020, observando prevalencias, porcentajes y comparación estadística con pruebas no paramétricas. Resultados: La prevalencia de casos por ingresos al programa de salud mental de atención primaria en salud/especialidad se mantuvo similar entre el primer semestre del año 2019 y el primer semestre del año 2020. La mayor proporción de casos de salud mental se concentran en los trastornos de humor (afectivos) y trastornos de ansiedad. Se observaron diferencias estadísticamente significativas entre el año 2019 y 2020 en el número de atenciones por ingresos en salud mental para los trastornos mentales y del comportamiento debido a consumo sustancias psicotrópicas, trastornos por consumo perjudicial o dependencia a drogas y trastornos de personalidad. Conclusión: Es prioritario que en Chile se aumente la cobertura en la atención primaria de salud mental, los datos entregados en este estudio muestran a nivel exploratorio que la situación inicial de la pandemia pudo haber afectado el acceso a la atención oportuna de las personas más vulnerables con trastornos de salud mental.

Modelling quarantine effects on SARS-CoV-2 epidemiological dynamics in Chilean communes and their relationship with the Social Priority Index.

Background: An epidemiological model (susceptible, un-quarantined infected, quarantined infected, confirmed infected (SUQC)) was previously developed and applied to incorporate quarantine measures and calculate COVID-19 contagion dynamics and pandemic control in some Chinese regions. Here, we generalized this model to incorporate the disease recovery rate and applied our model to records of the total number of confirmed cases of people infected with the SARS-CoV-2 virus in some Chilean communes. Methods: In each commune, two consecutive stages were considered: a stage without quarantine and an immediately subsequent quarantine stage imposed by the Ministry of Health. To adjust the model, typical epidemiological parameters were determined, such as the confirmation rate and the quarantine rate. The latter allowed us to calculate the reproduction number. Results: The mathematical model adequately reproduced the data, indicating a higher quarantine rate when quarantine was imposed by the health authority, with a corresponding decrease in the reproduction number of the virus down to values that prevent or decrease its exponential spread. In general, during this second stage, the communes with the lowest social priority indices had the highest quarantine rates, and therefore, the lowest effective viral reproduction numbers. This study provides useful evidence to address the health inequity of pandemics. The mathematical model applied here can be used in other regions or easily modified for other cases of infectious disease control by quarantine.

Preventive healthcare among dogs and cats in Chile is positively associated with emotional owner-companion animal bond and socioeconomic factors.

Global companion animal population has been increasing as well as the number of dogs and cats being considered as a family member. However, it is unclear whether this close relationship could be associated with higher preventive healthcare in companion animals. Using data from 7,048 questionnaires of dogs and 3,271 of cats from the First National Study on Responsible Companion Animal Ownership, we estimated the proportion of preventive healthcare in companion animals of Chile. We also conducted a general linear mixed-effect regression model to identify socioeconomic factors and indicators of the emotional owners-companion animal bond that could influence owners' practices related to vaccination, parasite control, and veterinary visits. Based on the owner's answers, Chile has a satisfactory overall rates of parasite control (71%) and annual veterinary visits (65%) but a low vaccination coverage of both dogs (39%) and cats (25%). 'Purebred', 'live in urban areas', 'acquired by monetary compensation', and 'dog species' were associated with a higher probability of preventive healthcare in companion animals. Conversely, this probability was lower among senior animals compared to adults, males, and those owned by the Silent Generation or Baby Boomers (i.e., owners born before 1964). 'Sleeping inside', 'acquired for an emotional reason' (e.g., companionship), and 'considered a family member' were positively associated with at least one of assessed preventive measures. Our findings suggest that emotional owner-companion animal bonds could positively impact the frequency and quality of preventive healthcare in dogs and cats. However, owners who totally disagreed that a companion animal is a "family member" were also associated with a higher likelihood of vaccination uptake and veterinary visits for their animals. This highlights that owner's compliance with veterinary preventive healthcare is multifactorial. Chile has a high prevalence of infectious diseases circulating among dogs and cats and increasingly close contacts between owners and companion animals due to emotional bonds. Thus, our study calls for One Health approaches to reduce the risks of cross-species disease transmission. Specifically, increasing vaccination coverage of companion animals in Chile is the most urgent preventive measure needed, especially among cats, males, and older animals. Expand preventive healthcare among dogs and cats will promote public and animal health, including local wildlife that is susceptible to infectious diseases circulating in companion animals.

The added effect of non-pharmaceutical interventions and lifestyle behaviors on vaccine effectiveness against severe COVID-19 in Chile: A matched case-double control study.

BACKGROUND: World Health Organization approved vaccines have demonstrated relatively high protection against moderate to severe COVID-19. Prospective vaccine effectiveness (VE) designs with first-hand data and population-based controls are nevertheless rare. Neighborhood compared to hospitalized controls, may differ in compliance to non-pharmacuetical interventions (NPI) compliance, which may influence VE results in real-world settings. We aimed to determine VE against COVID-19 intensive-care-unit (ICU) admission using hospital and community-matched controls in a prospective design. METHODS: We conducted a multicenter, observational study of matched cases and controls (1:3) in adults ≧18 years of age from May to July 2021. For each case, a hospital control and two community controls were matched by age, gender, and hospital admission date or neighborhood of residence. Conditional logistic regression models were built, including interaction terms between NPIs, lifestyle behaviors, and vaccination status; the model's ß coefficients represent the added effect these terms had on COVID-19 VE. RESULTS: Cases and controls differed in several factors including education level, obesity prevalence, and behaviors such as compliance with routine vaccinations, use of facemasks, and routine handwashing. VE was 98·2% for full primary vaccination and 85·6% for partial vaccination when compared to community controls, and somewhat lower, albeit not significantly, compared to hospital controls. A significant added effect to vaccination in reducing COVID-19 ICU admission was regular facemask use and VE was higher among individuals non-compliant with the national vaccine program, and/or tonroutine medical visits during the prior year. CONCLUSION: VE against COVID-19 ICU admission in this stringent prospective case-double control study reached 98% two weeks after full primary vaccination, confirming the high effectiveness provided by earlier studies. Face mask use and hand washing were independent protective factors, the former adding additional benefit to VE. VE was significantly higher in subjects with increased risk behaviors.

Perceived barriers and facilitators for adhering to COVID-19 preventive measures in Chile: a qualitative study in three large cities.

BACKGROUND: Globally, it has been reported that different social determinants of health -structural, sociodemographic, economic, living conditions and cultural factors- may affect opportunities to adhere to prevention measures against SARS-CoV-2. The objective of this study was to explore the perceptions around barriers and facilitators for adherence to COVID-19 prevention measures among the adult population residing in three large cities in Chile from a social determinants of health perspective. METHODS: Qualitative paradigm, multiple case-study design. Online semi-structured interviews were conducted with men and women aged 18 and over from different socioeconomic groups residing in three large cities. For participant recruitment and selection, purposive contacts were made based on community and social media networks, followed by snowball sampling. Saturation was reached at 61 participants, after which a thematic analysis was carried out with the support of AtlasTi software. The Ethics Committee of the Universidad del Desarrollo in Chile approved this study. RESULTS: The main perceived barriers to adherence to COVID-19 preventive measures are linked to structural social determinants of health such as income, occupation, gender, access to basic supplies, and housing. Perceived facilitators are the fear of contagion and the incorporation of measures into daily habits. The social communication of preventive measures by health authorities is perceived as punitive, affecting adherence once the fear of contagion decreased in the country. It is also perceived that the recommended preventive measures are disconnected from communities' cultural practices and people´s identity, as well as affected by gender inequities and socioeconomic conditions that stakeholders in the country do not sufficiently address. CONCLUSION: Study findings suggest that adherence to preventive measures, such as social distancing, mask use, and hand washing, could be promoted through their incorporation into the daily life habits of people and communities. These measures should consider the structural social determinants that generate multiple barriers to adherence, like poverty, occupational risks, and overcrowding. Socio-cultural dimensions of health and everyday risks need further understanding among the different communities in the country, allowing for differences in viewpoints and practices based on gender, age, place, and social identity.

COVID-19 pandemic and mental healthcare: Impact on health insurance with guaranteed universal access in Chile.

Background: Universal health coverage (UHC) is a goal of the member states of the United Nations. The negative impact of the COVID-19 pandemic on mental health, inequalities in access to care, and financing gaps set a problematic scenario for universal mental health coverage. In Latin America, depression and anxiety disorders have increased by more than 30%. Chile implemented a reform for UHC in 2005 generating a mandatory guaranteed plan for health insurance (GES) that covers schizophrenia, depression, bipolar disorders, and Alzheimer's disease. We assume that the pandemic increased cases of mental illness in GES of public and private insurance. Objectives: This study aimed to explore the effects of the pandemic on the use of the GES mental health plan of public and private insurance. Methods: A descriptive analysis of secondary data from public and private insurance on the use and expenditure of the GES plan in mental illness between 2005 and 2020 was carried out. An aggregate analysis of the use of psychiatric consultations without a guaranteed plan and sick leave was performed. Results: Between 2005 and 2020, 18.5% of GES cases corresponded to four mental health illnesses (1,682,021 cases). Public insurance covered 80% of cases. In the pandemic, cases of mental illness fell by 10.5% in public insurance and 28.7% in private ones, reducing spending by 33 and 6.2%, respectively. Psychiatric consultations without using the GES plan doubled in 2020 in private insurance, and medical discharges due to mental illness also increased. Leave due to mental illness increased by 20% in both types of insurance. Conclusion: The results suggest that the demand for mental healthcare increased during the pandemic, but public and private health insurance reduced admissions to the GES universal plan for schizophrenia, depression, and bipolar disorder. A universal guaranteed plan in an individual contribution system can have essential weaknesses for people when the principles of social security are not complied with, especially concerning the solidarity of the health insurance system.

Promoting the Participation of "Hard-to-Reach" Migrant Populations in Qualitative Public Health Research during the COVID-19 Pandemic in Chile.

The COVID-19 pandemic has further deepened socioeconomic and health inequities worldwide, especially among populations experiencing social vulnerability, such as international migrants. Sustained lockdowns and social distancing have raised challenges to conducting public health research with hard-to-reach populations. This study aims at exploring strategies to recruit "hard-to-reach" international migrants for qualitative public health research during the pandemic in Chile, based on the authors' experience. A retrospective qualitative evaluation process was carried out on the recruitment processes of three qualitative research projects focused on international migrants in Chile. All projects were implemented during the COVID-19 pandemic, demanding complementary and flexible strategies: (i) social media; (ii) snowball sampling; (iii) referrals from social workers and pro-migrant and migrant-led organizations; (iv) vaccination centers and healthcare centers; and (v) community-based recruitment. The strategies are qualitatively evaluated around seven emerging qualitative categories: (i) feasibility during lockdown periods; (ii) speed of recruitment; (iii) geographical coverage; (iv) sample diversity; (v) proportion of successful interviews; (vi) ethical considerations; and (vii) cost. Engaging hard-to-reach international migrants in public health research during the pandemic required constantly adapting recruitment strategies. Furthermore, relying on strategies that were not only Internet-based promoted the participation of populations with limited access to the Internet and low-digital literacy.

Norovirus, Hepatitis A and SARS-CoV-2 surveillance within Chilean rural wastewater treatment plants based on different biological treatment typologies.

During the COVID-19 pandemic, wastewater from WWTPs became an interesting source of epidemiological surveillance. However, there is uncertainty about the influence of treatment type on virus removal. The aim of this study was to assess viral surveillance within wastewater treatment plants (WWTPs) based on different biological treatments. Seasonal monitoring (autumn-winter and spring-summer) was conducted in 10 Chilean rural WWTPs, which were based on activated sludge, aerated lagoons, bio-discs, constructed wetlands, vermifilters and mixed systems. Viruses were measured (influent/effluent) by the RT-qPCR technique, using a commercial kit for SARS-CoV-2, NoV GI, NoV GII, and HAV. The detection of SARS-CoV-2 viral variants by genotyping was performed using SARS-CoV-2 Mutation Assays (ThermoFisher Scientific, USA). JC polyomavirus detection (control), as well as a qPCR technique. Results showed that SARS-CoV-2, NoV GI and GII were detected in influents at values between <5 and 462, 0 to 28, and 0 to 75 GC/mL, respectively. HAV was not detected among the studied WWTPs. The monitored WWTPs removed these viruses at percentages between 0 and 100 %. WWTPs based on activated sludge with bio-discs demonstrated to be the most efficient at removing SARS-CoV-2 (up to 98 %) and NoV GI and GII (100 %). Meanwhile, bio-discs technologies were the least efficient for viral removal, due to biofilm detachment, which could also adsorb viral aggregates. A correlation analysis established that solids, pH, and temperature are the most influential parameters in viral removal. Wastewater-based surveillance at WWTP allowed for the detection of Omicron before the Chilean health authorities notified its presence in the population. In addition, surveillance of viruses and other microorganisms could help assess the potential public health risk of wastewater recycling.

Seroprevalence of Natural and Acquired Immunity against the SARS-CoV-2 Virus in a Population Cohort from Two Chilean Cities, 2020-2022.

BACKGROUND: Chile has achieved the highest coverage for vaccines against the SARS-CoV-2 virus worldwide. OBJECTIVE: To assess the progression of immunity (natural and acquired by vaccine) in a cohort from two Chilean cities. METHODS: Individuals (n = 386) who participated in three phases of population-based serial prevalence studies were included (2020-2021 and 2022). Presence of SARS-CoV-2 antibodies was measured in serum. Data including time of vaccination and type of vaccine received were analysed with descriptive statistics. RESULTS: Seroprevalence was 3.6% in the first round and increased to 96.9% in the second and 98.7% in the third. In the third round, 75% of individuals who had received the basal full scheme were seropositive at 180 days or more since their last dose; 98% of individuals who received one booster dose were seropositive at 180 days or more, and 100% participants who received two boosters were seropositive, regardless of time since their last dose. Participants receiving mRNA vaccines had higher seroprevalence rates over time. CONCLUSIONS: The high vaccination coverage in Chile enabled the population to maintain high levels of antibodies. Vaccination boosters are essential to maintain immunity over time, which also depends on the type of vaccine administered.

Meteorological, PM2.5 and PM10 factors on SARS-COV-2 transmission: The case of southern regions in Chile.

There are several determinants of a population's health, including meteorological factors and air pollution. For example, it is well known that low temperatures and air pollution increase mortality rates in infant and elderly populations. With the emergence of SARS-COV-2, it is important to understand what factors contribute to its mitigation and control. There is some research in this area which shows scientific evidence on the virus's behavior in the face of these variables. This research aims to quantify the impact of climatic factors and environmental pollution on SARS-COV-2 specifically the effect on the number of new infections in different areas of Chile. At the local level, historical information available from the Department of Statistics and Health Information, the Chilean National Air Quality Information System, the Chilean Meteorological Directorate, and other databases will allow the generation of panel data suitable for the analysis. The results show the significant effect of pollution and climate variables measured in lags and will allow us to explain the behavior of the pandemic by identifying the relevant factors affecting health, using heteroskedastic models, which in turn will serve as a contribution to the generation of more effective and timely public policies for the control of the pandemic.

"If I get sick here, I will never see my children again": The mental health of international migrants during the COVID-19 pandemic in Chile.

BACKGROUND: The COVID-19 pandemic has had an impact on the mental health of international migrants globally. Chile has managed its response to the pandemic in an ongoing context of social unrest and combined regional migratory and humanitarian crisis. The country's population presents a high prevalence of common mental disorders and a high suicide rate, with limited access to mental healthcare. International migrants in Chile represent 8% of the total population, and although a socioeconomically heterogenous group, they face social vulnerability, a range of mental health stressors and additional barriers to access mental healthcare. This study describes the mental health outcomes, stressors, response, and coping strategies perceived by international migrants during the COVID-19 pandemic in Chile. METHODS AND FINDINGS: A qualitative case study was carried out through individual online interviews to 30 international migrants living in Chile during the pandemic and 10 experts of the social and health care sectors. An inductive content analysis was carried out, a process during which the researchers sought to identify patterns and themes derived from the data. Participants experienced mainly negative mental health outcomes, including anxiety and depression symptomatology. Stressors included the virus itself, work, living and socioeconomic conditions, discrimination, fear for their family and distance caring. Institutional responses to address the mental health of international migrants during the pandemic in Chile were limited and participants relied mainly on individual coping strategies. CONCLUSIONS: The pandemic can represent an important opportunity to strengthen mental health systems for the general population as well as for population groups experiencing social vulnerability, if the issues identified and the lessons learned are translated into action at national, regional, and international level. Promoting the mental health of international migrants means recognising migration as a social determinant of mental health and adopting a cross-cultural as well as a Human Rights approach.

Adding a reaction-restoration type transmission rate dynamic-law to the basic SEIR COVID-19 model.

The classical SEIR model, being an autonomous system of differential equations, has important limitations when representing a pandemic situation. Particularly, the geometric unimodal shape of the epidemic curve is not what is generally observed. This work introduces the ßSEIR model, which adds to the classical SEIR model a differential law to model the variation in the transmission rate. It considers two opposite thrives generally found in a population: first, reaction to disease presence that may be linked to mitigation strategies, which tends to decrease transmission, and second, the urge to return to normal conditions that pulls to restore the initial value of the transmission rate. Our results open a wide spectrum of dynamic variabilities in the curve of new infected, which are justified by reaction and restoration thrives that affect disease transmission over time. Some of these dynamics have been observed in the existing COVID-19 disease data. In particular and to further exemplify the potential of the model proposed in this article, we show its capability of capturing the evolution of the number of new confirmed cases of Chile and Italy for several months after epidemic onset, while incorporating a reaction to disease presence with decreasing adherence to mitigation strategies, as well as a seasonal effect on the restoration of the initial transmissibility conditions.

The Covid-19 Pandemic and Maternal Mental Health: A Longitudinal Study of Chilean and Foreign-Born Mothers.

Objectives: We explore the effects of the pandemic on stress, depressive symptoms and parenting practices of mothers with children aged between 24- and 30-months, residents in Santiago, Chile, and the differences between foreign-born and native-born mothers. Methods: Using data from the longitudinal project Mil Primeros Días and lagged-dependent models, we analyzed parental stress, depressive symptoms and parenting practices for native-born and foreign-born mothers. Lagged-dependent model allows us to take advantage of the longitudinal data by controlling for the previous score and baseline individual characteristics. Results: After 8 months of the pandemic, mothers of young children have more depressive symptoms, are more stressed, and show more hostility towards their children. Foreign-born mothers had 0.29 and 0.22 standard deviations (SD) more than native-born mothers in the parental distress and difficult child scales from the Parental Stress Index (PSI), respectively, and 0.17 SD more in the hostile-reactive parental behavior dimension. Conclusion: Findings suggest the need to implement policies and programs that prevent mental health deterioration for mothers, especially migrant mothers, to improve women's psychological condition and child wellness.