This article describes the application of spatial statistical epidemiological modeling and its inference and applies it to COVID-19 case data, looking at it from a spatial perspective, and considering time-series data. COVID-19 cases in Indonesia are increasing and spreading in all provinces, including Kalimantan. This study uses applied mathematics and spatiotemporal analysis to determine the factors affecting the constant rise of COVID-19 cases in Kalimantan. The spatiotemporal analysis uses the Geographically Temporally Weighted Regression (GTWR) model by developing a spatial and temporal interaction distance function. The GTWR model was applied to data on positive COVID-19 cases at a scale of 56 districts/cities in Kalimantan between the period of January 2020 and August 2021. The purpose of the study was to determine the factors affecting the cumulative increase in COVID-19 cases in Kalimantan and map the spatial distribution for 56 districts/cities based on the significant predictor variables. The results of the study show that the GTWR model with the development of a spatial and temporal interaction distance function using the kernel Gaussian fixed bandwidth function is a better model compared to the Ordinary Least Squares (OLS) model. According to the significant variables, there are various factors affecting the rise in cases of COVID-19 in the region of Kalimantan, including the number of doctors, the number of TB cases, the percentage of elderly population, GRDP, and the number of hospitals. The highest factors that affect COVID-19 cases are the high number of TB cases, population density, and the lack of health services. Furthermore, an area map was produced on the basis of the significant variables affected by the rise in COVID-19 cases. The results of the study provide local governments with decision-making recommendations to overcome COVID-19-related issues in their respective regions.

Obtaining a booster dose of coronavirus disease 2019 (COVID-19) vaccine is required to maintain the protective level of neutralizing antibodies and therefore herd immunity in the community, and the success of booster dose programs depends on public acceptance. The aim of this study was to determine the acceptance of a booster dose of COVID-19 vaccine and its drivers and barriers in Indonesia. A cross-sectional survey was conducted in the provinces of Indonesia between 1 and 15 August 2022. Individuals who completed the primary series of the COVID-19 vaccine were asked about their acceptance of a booster dose. Those who refused the booster dose were questioned about their reasons. A logistic regression was used to determine the determinants associated with rejection of a booster dose of COVID-19 vaccine. A total of 2935 respondents were included in the final analysis. With no information on the efficacy and safety of the COVID-19 vaccine, 95% of respondents agreed to receive a booster dose if it were provided for free by the government. This acceptance was reduced to only 50.3% if the vaccine had a 75% efficacy with a 20% chance of side effects. The adjusted logistic regression analysis indicated that there were eight factors associated with the rejection of the booster dose: age, marital status, religion, occupation, type of the first two vaccines received, knowledge regarding the importance of the booster dose, belief that natural immunity is sufficient to prevent COVID-19 and disbelief in the effectiveness of the booster dose. In conclusion, the hesitancy toward booster doses in Indonesia is influenced by some intrinsic factors such as lack of knowledge on the benefits of the booster dose, worries regarding the unexpected side effects and concerns about the halal status of the provided vaccines and extrinsic determinants such as the effectiveness and safety of the vaccine. These findings suggest the need for more campaigns and promotions regarding the booster dose benefits to increase its acceptance.

Willingness to pay (WTP) for booster doses of coronavirus disease 2019 (COVID-19) vaccines is an under studied research topic. Therefore, the current study aimed to investigate the WTP for the booster doses of COVID-19 vaccines and its predictors in Indonesia using an online survey distributed all over the provinces of this low-middle-income country. The WTP was evaluated using a basic dichotomous contingent valuation approach, and its associated determinants were evaluated using a linear regression model. Out of 2935 responders, 66.2% (1942/2935) were willing to pay for a booster dose of the COVID-19 vaccine. The majority of respondents (63.5%) were willing to pay within a price range of 100,000–500,000 Indonesian rupiah (IDR), i.e., USD 6.71–33.57. Being older than 40 years, having a higher educational level, having a higher income, knowing and understanding that booster doses were important, and having a vaccine status that is certified halal (permissible in Islamic law), were all associated with a higher WTP for the booster dose of COVID-19 vaccines. The study findings imply that the WTP for a booster dose of COVID-19 vaccination in Indonesia is lower compared to acceptance of vaccines provided free of charge. This WTP data can be utilized to develop a pricing scheme for the booster doses of COVID-19 vaccination in the country with potential benefits in other low-income countries. The government may be required to provide subsidies for the herd immunity vaccination process to proceed as anticipated. Furthermore, the public community must be educated on the importance of vaccination as well as the fact that the COVID-19 epidemic is far from being over.

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ABSTRACT Metformin is a first-line diabetes therapy but has one of the side effects which is a non-alcoholic fatty liver disease (NAFLD) that triggers the occurrence of fibrosis in the liver. Metformin nanoparticles can improve bioavailability and may reduce side effects. This study aims to analyze the effectiveness of metformin nanoparticle delivery through fasting blood glucose (FGB) levels and liver fibrosis in the diabetic rat model. This is experimental research with a post-test-only controlled group design. This study used 16 white male Wistar rats, 8 weeks of age, body weight (BW) 250-350 g. The streptozotocin (STZ) 40 mg/kg BW were injected i.p. Rats were divided into 4 groups; K1: normal control; K2: negative control (diabetes model); K3: diabetes model treated with metformin 100mg/kg BW; K4: diabetes model treated with nanoparticle metformin 100mg/kg BW. The BW and fasting blood glucose levels were conducted periodically. The histology of fibrosis was performed from Sirius Red staining of liver tissue and quantified using ImageJ software. The data were analyzed with GraphPhad Prism 8.0.0 using the non-parametric Kruskal-Wallis test. Metformin therapy decrease FBG levels on K3 starting on day 21 and K4 starting on day 7, but there was no statistical difference (p=0.0597). The areas of fibrosis were reduced (p=0.002). Metformin nanoparticles were able to decrease FBG levels and effectively reduce the formation of liver fibrosis in the diabetic rat model.   Keywords: diabetes, fibrosis, metformin, nanoparticles   ABSTRAK Metformin merupakan terapi lini pertama diabetes, namun memiliki efek samping yaitu non-alcoholic fatty liver disease (NAFLD) yang memicu terjadinya fibrosis pada hati. Sediaan nanopartikel metformin dapat meningkatkan bioavailabilitas dan dapat mengurangi efek sampingnya. Tujuan penelitian ini untuk menganalisis efektivitas penghantaran sediaan nanopartikel metformin terhadap kadar glukosa darah puasa (GDP) dan fibrosis hati pada tikus model diabetes. Penelitian ini merupakan eksperimental dengan post-test only controlled group design. Penelitian ini menggunakan 16 ekor tikus putih galur Wistar jantan, berusia 8 minggu, berat badan (BB) 250-350 g. Tikus diinjeksikan streptozotocin (STZ) dosis 40 mg/kg BB. Tikus dibagi dalam 4 kelompok perlakuan; K1: kontrol normal; K2: kontrol negatif (model diabetes); K3: model diabetes + terapi metformin 100mg/kgBB; K4: model diabetes + terapi sediaan nanopartikel metformin 100mg/kg BB. Pengukuran BB dan GDP secara berkala. Area fibrosis didapatkan dari pewarnaan Sirius Red jaringan hati tikus, dan dikuantifikasi menggunakan perangkat lunak ImageJ. Data dianalisis dengan GrapPhad Prism 8.0.0 menggunakan uji non parametrik Kruskal-Wallis. Hasil penelitian ini menunjukkan terapi metformin menurunkan kadar GDP pada K3 mulai pada hari ke-21 dan K4 mulai hari ke-7, namun tidak berbeda secara statistik (p=0,0597). Luas area fibrosis mengecil (p=0,002). Kesimpulan penelitian ini sediaan nanopartikel metformin mampu menurunkan kadar GDP dan efektif mengurangi terbentuknya fibrosis hati pada tikus model diabetes.   Kata kunci: diabetes, fibrosis, metformin, nanopartikel