The Covid-19 pandemic has caused great changes worldwide leading to stressful emotions of insecurity about the future and abrupt differentiations in the daily routine of millions of people during a short time period. In the same vein, it proved that, despite the great progress in medicine, continuous vigilance is necessary. The history of mankind has witnessed quite a few epidemics but the transmission of infectious disease may nowadays be easier than ever before due to the current lifestyle. Mass disaster phenomena pose a challenge for the psychological resilience of persons and societies since everybody must adapt to a new situation that demands rapid and forced changes in pervasive parts of daily life. Additionally, they may lead to manifestation of intense stress and other psychiatric symptoms in cases when health status, or even life itself, seem to be in danger. People react to such situations in various ways, but societies, as organized groups, usually react by increasing their cohesion and their social solidarity, and by supplying help to people or groups who need it. In the first period, during which attempts are made and measures are implemented in order to manage the sanitarian consequences of the pandemic, many people may manifest intense anxiety and other psychopathological symptoms. These people, including those belonging to more vulnerable groups (e.g., patients suffering from chronic mental disorders), may need psychological support interventions. When these consequences subside, the need for an organized approach to the treatment of the psychological consequences of the pandemic may become apparent. These consequences may result from facts such as the acute changes enforced in the daily life, the financial and vocational problems, the sense of insecurity about the future and the loss of beloved ones. The current Covid-19 pandemic, with such a totally new extent and intensity of effects for the humanity, provides an occasion to delve with the psychology of people under these circumstances. The paper gives a brief report of the psychological responses in both individual and group basis. Furthermore, it refers to the psychological effects of quarantine and to vulnerability factors that could lead to the manifestation of psychopathological symptoms during pandemics.