Publications by authors named "Tsolmon Bilegtsaikhan"

Background: Data on changes in pneumococcal serotypes in hospitalised children following the introduction of the pneumococcal conjugate vaccine (PCV) in low-income and middle-income countries are scarce. In 2016, Mongolia introduced the 13-valent PCV (PCV13) into the national immunisation programme. We aimed to describe the trend and impact of PCV13 introduction on pneumococcal carriage in hospitalised children aged 2-59 months with pneumonia in Mongolia over a 6-year period.

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Article Synopsis
  • A study assessed the long-term effects of the 13-valent pneumococcal conjugate vaccine (PCV13) on pneumococcal carriage in infants and toddlers in Asia, with surveys conducted before (2015) and after (2017, 2022) its introduction.
  • The findings revealed a decrease in carriage of PCV13 serotypes and a drop in resistance genes among toddlers six years after the vaccine was introduced, although overall pneumococcal density increased.
  • The most common non-vaccine serotype identified in 2022 was Serotype 15A, mainly linked to a specific genetic lineage, suggesting that tracking these changes is vital for future vaccine development.
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Background: Hepatocellular carcinoma (HCC) is the most common cancer in Mongolia. The relative importance of hepatitis B virus (HBV) and hepatitis C virus (HCV) infections in HCC etiology is known to vary greatly from one part of the world to another. Principally, 95% of HCC patients have chronic viral hepatitis, including 53% hepatitis B virus, 38.

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Background: Data available for RSV and influenza infections among children < 2 years in Mongolia are limited. We present data from four districts of Ulaanbaatar from April 2015 to June 2021.

Methods: This study was nested in an enhanced surveillance project evaluating pneumococcal conjugate vaccine (PCV13) impact on the incidence of hospitalized lower respiratory tract infections (LRTIs).

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Objectives: Limited data indicate a beneficial effect of pneumococcal conjugate vaccines (PCVs) on respiratory syncytial virus (RSV) and influenza infections in young children. We evaluated the impact of 13-valent PCV (PCV13) introduction on the incidence of severe lower respiratory tract infections (LRTIs) associated with RSV or influenza in hospitalized children.

Methods: Our study was restricted to children aged <2 years with arterial oxygen saturation <93% and children with radiologically confirmed pneumonia nested in a pneumonia surveillance project in four districts of Ulaanbaatar city, Mongolia.

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Starting in June 2016, the 13-valent pneumococcal conjugate vaccine (PCV13) was introduced into the routine immunization program of Mongolia by using a 2+1 dosing schedule, phased by district. We used prospective hospital surveillance to evaluate the vaccine's effect on pneumonia incidence rates among children 2-59 months of age over a 6-year period. Of 17,607 children with pneumonia, overall adjusted incidence rate ratios showed decreased primary endpoint pneumonia, very severe pneumonia, and probable pneumococcal pneumonia until June 2021.

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Background: COVID-19 vaccine booster doses restore vaccine effectiveness lost from waning immunity and emerging variants. Fractional dosing may improve COVID-19 booster acceptability and uptake and will reduce the per-dose cost of COVID-19 booster programmes. We sought to quantify the immunogenicity, reactogenicity, and safety of a half-dose BNT162b2 (Pfizer-BioNTech) booster relative to the standard formulation.

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Background: Coronavirus disease (COVID-19) has had a significant impact globally, and extensive genomic research has been conducted on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) lineage patterns and its variants. Mongolia's effective response resulted in low prevalence until vaccinations became available. However, due to the lack of systematically collected data and absence of whole genome sequencing capabilities, we conducted a two-stepped, nationally representative molecular epidemiologic study of SARS-CoV-2 in Mongolia for 2020 and 2021.

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Background: Few studies have assessed the potential indirect effects of childhood pneumococcal conjugate vaccine (PCV) programs on the adult pneumonia burden in resource-limited settings. We evaluated the impact of childhood PCV13 immunisation on adult all-cause pneumonia following a phased program introduction from 2016.

Methods: We conducted a time-series analysis to assess changes in pneumonia hospitalisation incidence at four district hospitals in Mongolia.

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The SARS-CoV-2 vaccination campaign began in February 2021 and achieved a high rate of 62.7% of the total population fully vaccinated by August 16, 2021, in Mongolia. We aimed to assess the initial protective antibody production after two doses of a variety of types of SARS-CoV-2 vaccines in the Mongolian pre-vaccine antibody-naïve adult population.

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Background: A nationwide vaccination program against coronavirus disease 2019 (COVID-19) was started in Mongolia 4 months after the first local transmission, which occurred in November 2020. Previous studies have reported that two doses of COVID-19 vaccine result in increased antibody against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). A study was conducted in Mongolia 2 weeks after the second vaccine dose.

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Article Synopsis
  • Community-acquired pneumonia is a significant health issue globally, especially in low- and middle-income countries, where its impact on adults is under-studied.
  • A study analyzed over 4,000 respiratory admissions in Ulaanbaatar, finding that severe pneumonia primarily affects older adults and is more common in men and individuals with existing health issues.
  • From 2015 to 2018, the incidence of pneumonia in adults increased, with the highest rates observed in those aged 65 and older, highlighting the need for targeted vaccination and prevention strategies.
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Introduction: The study was focused on comparing crude and sex-adjusted hazard ratio calculated by the baseline variables which may have contributed to the severity of the disease course and fatal outcomes in Coronavirus Disease-19 (COVID-19) patients.

Method: The study enrolled 150 eligible adult patients with confirmed SARS-CoV-2 infection. There were 61 (40.

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Mongolia was listed among the 30 countries with a high tuberculosis burden in 2021. Approximately 10-11% of the tuberculosis cases are of children, which is higher than the global average (6.0%).

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  • Distant metastasis from breast cancer contributes significantly to mortality, with E-selectin on endothelial cells facilitating cancer cell movement through its interaction with CD44.
  • The study examined how soluble E-selectin (sE-selectin) affects the adhesion and migration of breast cancer cells and leukocytes, finding it specifically promoted these processes in CD44(+) cancer cell lines.
  • sE-selectin increased adhesion and migration through pathways involving CD44 and FAK, as well as enhanced infiltration of cancer cells into tissues, indicating sE-selectin's role in tumor progression and metastasis.
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The medical applications of aptamers have recently emerged. We developed an antagonistic thioaptamer (ESTA) against E-selectin. Previously, we showed that a single injection of ESTA at a dose of 100μg inhibits breast cancer metastasis in mice through the functional blockade of E-selectin.

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We performed a genome-wide association study with 23,465 microsatellite markers to identify genes related to adult height. Selective genotyping was applied to extremely tall and extremely short individuals from the Khalkh-Mongolian population. Two loci, 8q21.

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