CalScope: Monitoring SARS-CoV-2 Seroprevalence from Vaccination and Prior Infection in Adults and Children in California May 2021– July 2021

ABSTRACTImportanceUnderstanding how SARS-CoV-2 seroprevalence varies regionally across California is critical to the public health response to the pandemic.ObjectiveTo estimate how many Californians have antibodies against SARS-CoV-2 from prior infection or vaccination.DesignWave 1 of CalScope: a repeated cross-sectional serosurvey of adults and children enrolled between April 20, 2021 and June 16, 2021.SettingA population-based random sample of households in seven counties in California (Alameda, El Dorado, Kern, Los Angeles, Monterey, San Diego, and Shasta) were invited to complete an at-home SARS-CoV-2 antibody test and survey instrument.ParticipantsInvitations were sent to 200,000 randomly selected households in the seven counties. From each household, 1 adult (18 years and older) and 1 child (aged 6 months to 17 years) could enroll in the study. There were no exclusion criteria.Main Outcome(s) and MeasuresAll specimens were tested for antibodies against the nucleocapsid and spike proteins of SARS-CoV-2. The primary outcome was serostatus category, which was determined based on antibody test results and self-reported vaccination status: seronegative, antibodies from infection only, antibodies from infection and vaccination, and antibodies from vaccination alone. We used inverse probability of selection weights and iterative proportional fitting to account for non-response.Results11,161 households enrolled in wave 1 of CalScope, with 7,483 adults and 1,375 children completing antibody testing. As of June 2021, 27% (95%CI [23%, 31%]) of adults and 30% (95%CI [24%, 36%]) of children had evidence of prior SARS-CoV-2 infection; 33% (95%CI [28%, 37%]) of adults and 57% (95%CI [48%, 66%]) of children were seronegative. Serostatus varied regionally. Californians 65 years or older were most likely to have antibodies from vaccine alone (59%; 95%CI [48%, 69%]) and children between 5-11 years old were most likely to have antibodies from prior infection alone (36%; 95%CI [21%, 52%]).Conclusions and RelevanceAs of June 2021, a third of adults in California and most children under 18 remained seronegative. Seroprevalence varied regionally and by demographic group, suggesting that some regions or populations might remain more vulnerable to subsequent surges than others.Key PointsQuestionWhat is the prevalence of vaccine and infection derived antibodies against SARS-CoV-2 in adults and children in California?FindingsIn this population-based serosurvey that included 11,161 households, as of June 2021, 33% of adults and 57% of children were seronegative; 18% of adults and 26% of children had antibodies from infection alone; 9% of adults and 5% of children had antibodies from both infection and vaccination; and 41% of adults and 13% of children had antibodies from vaccination alone.MeaningSerostatus varied considerably across geographic regions, suggesting that certain areas might be at increased risk for future COVID-19 surges.

Examining Vaccine Hesitancy in Sub-Saharan Africa: A Survey of the Knowledge and Attitudes among Adults to Receive COVID-19 Vaccines in Ghana

The impact of COVID-19 vaccination programmes on disease transmission, morbidity and mortality relies heavily on the population’s willingness to accept the vaccine. We explore Ghanaian adult citizens’ vaccine hesitancy attitudes and identify the likelihood of participation or non-participation in the government’s effort to get citizens vaccinated. A fully anonymised cross-sectional online survey of 2345 adult Ghanaians was conducted from 23 to 28 February 2021. Differences in intentions regarding COVID-19 vaccination were explored using Pearson Chi-square tests. Additionally, multinomial logistic regression was used to analyse the factors associated with willingness to receive vaccines. Responses were weighted using the iterative proportional fitting technique to generate a representative sample. About half (51%) of mostly urban adult Ghanaians over 15 years are likely to take the COVID-19 vaccine if made generally available. Almost a fifth (21%) of the respondents were unlikely to take the vaccine, while another 28% were undecided. Additionally, we find differences in vaccine hesitancy among some socio-demographic characteristics such as age, gender, and primary sources of information. Attaining the proverbial 63% to 70% herd immunity threshold in Ghana is only possible if the preventive vaccination programmes are combined with an enhanced and coordinated public education campaign. Such a campaign should focus on promoting the individual and population-level benefits of vaccination and pre-emptive efforts towards addressing misinformation about vaccines.

High Engagement of Patients Monitored by a Digital Health Ecosystem Indicates Significant Improvements of Key r-hGH Treatment Metrics

The early adoption of digital health solutions in the treatment of growth disorders has enabled the collection and analysis of more than 10 years of real-world data using the easypod™ connect platform. Using this rich dataset, we were able to study the impact of engagement on three key treatment-related outcomes: adherence, persistence of use, and growth. In total, data for 17,906 patients were available. The three features, regularity of injection (≤2h vs >2h), change of comfort setting (yes/no), and opting-in to receive injection reminders (yes/no), were used as a proxy for engagement. Patients were assigned to the low-engagement group (n=1,752) when all of their features had the low-engagement flag (>2h, no, no) and to the high-engagement group (n=1,081) when all of their features had the high-engagement flag (≤2h, yes, yes). The low-engagement group was down-sampled to 1,081 patients (subsample of n=37 for growth) using the iterative proportional fitting algorithm. Statistical tests were used to study the impact of engagement to the outcomes. The results show that all three outcomes were significantly improved by a factor varying from 1.8 up to 2.2 when the engagement level was high. These results should encourage the promotion of engagement and associated behaviors by both patients and healthcare professionals.

Generating and Visualizing Spatially Disaggregated Synthetic Population Using a Web-Based Geospatial Service

Geographically fine-grained population information is critical for various urban planning and management tasks. This is especially the case for the Chinese cities that are undergoing rapid development and transformation. However, detailed population data are rarely available in comprehensive and timely means. Therefore, appropriate approaches are needed to estimate populations from available data sets in a systematic way to support the continuous demand from urban analytics and planning. Population synthesis approaches such as Iterative Proportional Fitting (IPF) were developed to combine microdata samples with marginal statistics about population characteristics at aggregated spatial levels in order to expand the microdata sample into a complete synthetic population. This paper presents the framework for and the implementation of a geospatial platform for supporting the generation and exploration of spatially detailed urban synthetic populations. The platform provides analytical and visualization tools to support the quick generation of a full urban population with critical attributes based on the latest data available. The case of the synthetic population of Chongqing is used to illustrate the population information and types of visualization that are facilitated.

Spatial Microsimulation Combined with Skater Regionalization Methods: A Study for the Paraíba Valley and North Coast Metropolitan Region Subregion 4 in the São Paulo State

This study analyzes the socio-occupational distribution in the Paraíba Valley and North Coast Metropolitan Region (in Portuguese: Região Metropolitana do Vale do Paraíba e Litoral Norte – RMVPLN) Subregion 4 using spatial microsimulation techniques. To fulfill the proposed objective, the Iterative Proportional Fitting (IPF) technique was used to obtain spatial microdata in the territorial census tracts unit through the 2010 Brazilian Demographic Census. After the Skater regionalization technique was applied, eight homogeneous socio-occupational groups were found. Overall, the proposed socio-occupational categories, studied at an intra-urban scale, allowed for highlighting the social structure on a subregion of the newest Metropolitan space in the São Paulo state. Although this is a preliminary study, it is already capable to identify inequalities degrees that consistently spatially segregate and the less privileged population socioeconomic groups.

Generation of a synthetic population for agent-based transport modelling with small sample travel survey data using statistical raster census data

This paper presents a step-by-step method to generate a synthetic population for agent-based transport modelling as input to MATSim software, which requires an activity chain for each agent. We make use of high spatial resolution statistical raster (250 m) census data, applying all calculations at this scale. Due to the small sample, size of travel survey data an Iterative Proportional Fitting method is not suitable. Therefore, we devise a method utilizing Bayesian networks, maximum likelihood and Markov Chain Monte Carlo simulation to reproduce attribute distribution and fit to raster margins. Stratified sampling along households is employed to generate activity chains for the synthetic population.

A municipal database from the 2011 Spanish census

Purpose The paper aims to describe the process to obtain a complete municipal database from the 2011 Spanish Census information. By complete, the authors mean variables for the full sample of the 8,116 municipalities as of the census reference date. In addition, the database should be consistent with the public census information released by the National Statistical Institute: microdata and customized tables. Design/methodology/approach The authors use mainly small area demographic and synthetic estimators that are reconciled using biproportional adjustment (iterative proportional fitting), when needed. Findings As a result, the authors obtain a complete and consistent municipal database composing 55 variables related to socio-demographic characteristics of persons. Originality/value The provision of a complete and consistent municipal database, available for download, which is absent in the original 2011 Spanish Census.

Updates to the ipfraking ecosystem

Kolenikov (2014, Stata Journal 14: 22–59) introduced the package ipfraking for iterative proportional fitting (raking) weight-calibration procedures for complex survey designs. In this article, I briefly describe the original package and updates to the core program and document additional programs that are used to support the process of creating survey weights in the author’s production code.