Background: Natural protection against Mycobacterium tuberculosis is based on cell-mediated immunity, which most importantly involves CD4+ and CD8+ T-cell subsets. Therefore, the evaluation of CD4+ and CD8+ T-cell profi les are important to evaluate cell-mediated immunity. Immuno-regulating therapy is important in increase of T cell subsets. Objective: To determine some T-cell subsets in active pulmonary tuberculosis patients following immunoregulating treatment in intensive phase of antituberculosis treatment, so to evaluate the treatment effect. Method: This study was conducted in TB clinic of National Center for Communicable Diseases (NCCD) between Aug 2008 and Mar 2009. CD4+ and CD8+-T cells were evaluated in 50 active pulmonary tuberculosis (infi ltrative form) cases before antituberculosis treatment (25 cases with Salimon-Study group, 25 cases without SalimonControl group) Patients with chronic disease, pregnant and alcohol users are excluded. The T cell subsets count was performed by FACSCount fl ow cytometer at the Immunology Laboratory of the NCCD,Mongolia.The monoclonal antibodies to CD3, CD4 and CD8 (Becton Dickinson) were used for the analysis. Result: CD4 count was 605,1242,7 cells/microL, CD8 count-470,92235,7 cells/microL, CD3 count-1130,7425,6 cells/microL, CD4/CD8 ratio was-1,480,67. CD4, CD8, CD3 cells were signifi cantly lower (P=0.05) in active pulmonary TB patients than in healthy Mongolian. And these subsets were signifi cantly lower in older patients (>50 age).There was no statistical signifi cance in sex and other age groups (p>0, 05). There were statistical signifi cances such as CD4 count, CD4/CD8 ratio (CD4-733,95314,38 cells/micro, CD4/CD8 ratio-1.870,7 in treatment group, CD4-570,54213.07 cells/micro, CD4/CD8 ratio-1.260.45 in control group) between TB and control group at the end of intensive phase of antituberculosis treatment (=0,05, =0,001). However, there were not any signifi cance CD8 count and CD3 count between two groups (CD8-423,68174,28 cells/microL, CD3-1212,27453,98 cells/microL in treatment group, CD8-500,67203,74cells/microL, CD3 -1139,33 386,47 cells/ microL in control group) (=0,05). Conclusion: 1. T cell subsets were signifi cantly lower in active,new,smear positive, pulmonary TB patients than in healthy Mongolians (p=0.05). 2. The statistical signifi cance is observed in 50 years and older TB patients (p=0.05). 3. CD4, CD4/CD8 were signifi cantly higher in patients treated with immuno-regulating treatment than in patients of control group (=0,05, =0,001).

Background: To prevent and combat the spread of the COVID-19 pandemic, the Government of Mongolia has implemented measures such as movement and time restrictions, social distancing and isolation, closure of schools, kindergartens and public places, immunization, and others. It has caused adverse consequences for people, social relations, and the economy, causing health, social, economic, and humanitarian crises. Not only does this situation, medical students, as frontline healthcare workers, are more susceptible to virus infection. Vaccines against COVID-19 have been researched quickly due to the pandemic and are being used under emergency use authorization. In our country the approach of mixing vaccine doses from different manufacturers was used (fractional doses). Therefore, there is no study on the exposure of medical students to the COVID-19 infection and the adverse effects after receiving a dose of a heterologous vaccine. Objective: To study the exposure to the COVID-19 infection and vaccination status of medical students. Methods: The survey was conducted from November 2023 to December 2023 using a cross-sectional study design, and 170 students who study at ASUSU and live in the dormitory were included. Results: A total of 170 students participated in the study. 55.9% (n=95) of them were in the first year, 22.4% (n=38) were in the second year, 10% (n=17) were in the third year, 7.6% (n=13) were in the fourth year, 2.4% (n=4) were from the 5th year and 1.8% (n=3) were from the 6th year students. 88.2% (n=150) of students were female and 11.8% (n=20) were male. In this study, 37.1% of the students were infected by COVID-19 infection previously. Among them, 50% of the students were infected from family members, 16.7% from the school environment, and 15.2% did not know about the source of infection. 76.2% of the respondents were diagnosed with COVID-19 in a medical institution, and forty-one students answered that they were treated at the hospital. 83% of the cases were treated at home and were cured within 14 days. In contrast, 93.8% of the hospitalized students were treated within four months to 1 year. The current study demonstrates neurological, respiratory, sensory, cardiovascular, psychiatric, digestive, and dermatological symptoms were in 37.6%, 24.1%, 27.6%, 17.6%, 11.8%, 11.2%, and 10% of the students who participated in the study, respectively. For a year or more, symptoms of all organ systems were present, but neurological symptoms appeared to be the highest. 55.9% (n=115) of the enrolled students received 3 or 4 doses of the vaccine, 3.5% (n=6) did not receive the vaccine. In total, 35% (n=60) of the enrolled students experienced side effects and 65% (n=106) had no side effects. Conclusion In this study, 37.1% of the students were infected by COVID-19 infection previously. According to the current study, symptoms related to the nervous system was the most prevalent and 55.9% (n=115) of the enrolled students received 3 or 4 doses of the vaccine. In total, 35% (n=60) of the enrolled students experienced side effects.