SARS-CoV-2, the third coronavirus associated with severe respiratory infections in humans, spreads more easily and quickly in the community, with a higher infectiousness rate compared to the other two betacoronavirus species (SARS-CoV and MERS-CoV). The SARS-CoV-2 pandemic, in which the number of cases worldwide has exceeded 30 million, has been the biggest global epidemic of the last century with serious concerns and socio-economic impacts. Educational activities, meetings, worship, tourism,

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... ade and sports organizations came to a halt in many countries during the pandemic period and national and international travel restrictions were applied. Also, in most countries, to protect the population at risk and to slow/stop the spread of infection; nationwide or regional curfew restrictions have been imposed according to risk analysis, and public health measures such as the obligation to wear a mask and quarantine precautions have been taken. The starting time of implementation of these measures, duration and controlling of the restrictions has been one of the important parameters determining the degree of countries affected by the epidemic. Studies on transmission routes of SARS-CoV-2 infections provide new information on epidemiological, immunological and virological parameters that are effective in the community spread of the virus. Epidemiological parameters generally include age, gender, presence of concomitant diseases/conditions, sociocultural habits, the role of asymptomatic persons and reservoir animals, seasonality of infections. Immunological factors include conditions associated with the immune response, such as susceptible individuals with immunodeficiency, the role of people who shed the virus for a long time, the level and duration of protective immunity in recovered people, effectiveness of active and passive immunization, the importance of viral load in the transmission and clinical course. Among the virological parameters that can affect the spread of the infection include the resistance of the virus to environmental conditions and disinfectants, receptor affinity and the degree of adaptation to humans, possible mutations associated with immune escape and virulence. In this article, by mentioning the situations that may pose a risk for the transmission, social spread and clinical course of infections, the main protective measures under the related topics are highlighted.