Highlights d Antibodies to four COVID-19 vaccines differed in an observational study in Mongolia d Responses from high to low: Pfizer/BioNTech > AstraZeneca > Sputnik V > Sinopharm d Breakthrough infections in June to early July of 2021 were due mostly to the Alpha variant d After breakthrough infection, high antibody levels are seen in all vaccine groups

In this study, a representative group of Mongolian adults was tested for hepatitis B virus (HBV) and hepatitis C virus (HCV). Screening was conducted at 17 different locations on a randomly sampled group, representing the Mongolian adult population. A total of 1158 adults, 500 (43.1%) men and 659 (56.9%) women were included. The prevalence estimates of HBV and HCV amongst the general Mongolian adult population were found to be 11.1%±1% (SE) and 8.5%±0.7% or 207 418 and 160 228 cases, respectively. For HCV, the majority of cases are concentrated in older age groups with a prevalence of 25.8% amongst those aged 50 years and above, whilst the prevalence of HBV does not vary significantly amongst age groups. For both, HBV and HCV, the data indicate a higher risk of infection and a higher mortality because of the hepatitis amongst men than amongst women. This study represents the first nationwide estimate of the prevalence of HBV in Mongolia and also considered the first for HCV since 2005 and confirm the position of Mongolia as one of the hot-spots of chronic hepatitis infection in the world with about 19.4% of the adult population being infected with either HBV or HCV.

Objectives: This study was conducted to determine the effect of Hepatitis B infection with or without D coinfection on the hepatitis flare associated with chemotherapy for B-Cell non-Hodgkin lymphoma. Methods: The hepatitis flare related to the chemotherapy for newly diagnosed B-Cell non-Hodgkin lymphoma was studied in HBV mono-infected and HBV and HDV coinfected patients between 2015 and 2018. Results: Nineteen HBsAg positive patients satisfied the inclusion criteria. In the group with the hepatitis flare, 14.3% were anti-HDV negative and 83.3% were anti-HDV positive (p<.006). Also, the hepatitis flare occurred in all patients where HDV-RNA was detected, while it had occurred in 60% of patients where HDV-RNA was not detected. Conclusion: The hepatitis flare related to chemotherapy occurred more frequently in B-Cell non-Hodgkin lymphoma patients coinfected with HBV and HDV without antiviral prophylaxis, especially when HDV-RNA was detected.

Different vaccines for SARS-CoV-2 are approved in various countries, but few direct comparisons of the antibody responses they stimulate have been reported. We collected plasma specimens in July 2021 from 196 Mongolian participants fully vaccinated with one of four Covid vaccines: Pfizer/BioNTech, AstraZeneca, Sputnik V and Sinopharm. Functional antibody testing with a panel of nine SARS-CoV-2 viral variant RBD proteins reveal marked differences in the vaccine responses, with low antibody levels and RBD-ACE2 blocking activity stimulated by the Sinopharm and Sputnik V vaccines in comparison to the AstraZeneca or Pfizer/BioNTech vaccines. The Alpha variant caused 97% of infections in Mongolia in June and early July 2021. Individuals who recover from SARS-CoV-2 infection after vaccination achieve high antibody titers in most cases. These data suggest that public health interventions such as vaccine boosting, potentially with more potent vaccine types, may be needed to control the COVID-19 pandemic in Mongolia and worldwide.

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