COVID-19(6) mortality rate(2) phases of the pandemic(2) case fatality ratio(2) infection fatality ratio(2) Coronavirus infection(2) polymerase chain reaction.(2) SARS-CoV-2(2) civil liability(1) age groups of the population(1) coronavirus(1) recreational potential(1) Antibiotic resistance(1) International student(1) export of medical services(1) information technology.(1) circulation(1) pandemic(1) Health care(1) sanitary hygienic practices(1) health tourism(1) Life satisfaction(1) prevention(1) Efficiency(1) morbidity(1) next-generation sequencing.(1) viral hepatitis E(1) hygienic status(1) primary morbidity.(1) Russia(1)