The mental health effects of the coronavirus disease 2019 (COVID-19) pandemic may shape population health for many years to come.Failure to address the mental health issues stemming from the pandemic is likely to prolong its impact.The COVID-19 pandemic has created a significant global challenge and,in lower-income countries,even a disruption of mental health services.Given our experience with previous pandemics,the present COVID-19 crisis can be expected to cause psychological trauma,and steps are needed to address this issue proactively.Policies focusing on the long-term mental health consequences of COVID-19 may equal the importance of those currently seeking to mitigate its physical effects.The implications of the GOVID-19 pandemic for mental health call for a greater focus on the needs of those with mental disorders and on mental health issues affecting health care workers and the general public.Timely preventive and therapeutic mental health care is essential in addressing the psychosocial needs of populations exposed to the pandemic.In addition to specialist care,"task-shifting" and digital technologies may provide cost-effective means of providing mental health care in lower-income countries worldwide as well as in higher-income countries with mental health services overwhelmed by the effects of the COVID-19 pandemic.In view of the ever-increasing pressure on global health systems resulting from the COVID-19 pandemic,adopting and adapting "task-shifting",i.e.,the delegation of psychotherapeutic interventions to trained non-specialists,as an element of the provision of mental health services,is overdue.Digital technologies can be used to enhance social support and facilitate resilience to the detrimental mental health effects of the pandemic;they may also offer an efficient and cost-effective way to provide easy access to mentalhealth care.

A global disparity exists between the burden of mental ill-health and the resources available to address this is-sue.Common mental disorders,such as mild-to-moderate depression,anxiety disorders and post-traumatic stress disorder,are associated with a significant decline in health and functioning and contribute significantly to the overall burden of disease.In view of a shortage of mental health professionals in most low-and middle-income countries,task sharing (task shifting) can make an important contribution to improving access to mental health services.Task sharing involves non-specialists in the delivery of health care.The use of lay health workers is premised on the assumption that the shorter training required for non professionals will allow an increase in the provision of required care without the need for an increase in resources and will strengthen and scale-up sustainable health systems.The need for low-tech support in the management of common mental disorders is widespread,and the core resource is humans trained to identify and treat those requiting mental health care.There is a strong evidence base for the effectiveness of task sharing in psychotherapy,and talk therapies,e.g.cognitive behavioral therapy,can easily be delegated to non-specialists,including non-specialist health work-ers,peer helpers and lay people.A (cost-) effective model of mental health care in low-resource settings as well as in high-income countries may include the medical school-based training of some psychiatrists and clinical psychologists in the treatment of referred patients with serious mental illness.These professional mental health specialists would also be trainers and supervisors of non-specialist health workers who would identify common mental health disorders and provide psychotherapy to people with these conditions in a community-based set-ring.Community-based generalism including task sharing rather than centralized specialism may be capable of preventing and treating many common mental disorders with minor financial expenditure.

The German pathologist and politician Rudolf Virehow proposed the concept of sociomedical causation,em-phasising the role of social and environmental factors in the aetiology and prevention of diseases.Virchow's achievements are threefold:he was a founder of scientific biomedicine,he characterised medicine as a social science as much as a biological science and he promoted and improved public health.In his landmark report of a typhus epidemic in mid-19th century Germany,Virchow drew a connection between the epidemic and poverty and living conditions.He proposed radical social reform and stated that,"medicine is social science and politics nothing but medicine on a grand scale".The task of medicine was therefore not merely to treat disease but also to contribute to the health of the entire population.Virchow realised that,in order to improve the health of the public,medicine must attend to both its biological and social underpinnings.His work has had far-reaching con-sequences for the development of public health and medical sociology.As in Virchow's times,poverty,deprived living conditions,malnutrition,crowding and economic insecurity determine to a high degree the prevalence of disease and life expectancy in low-and middle-income countries today.Sociomedical causation is not limited to infectious diseases but also extends to the contemporary pandemics of non-communicable diseases.Obesity and other non-communicable diseases cannot be addressed effectively without considering and acting on the social determinants of health.The concept of "health in all policies" has emerged with the goal of promoting political action addressing the social determinants of health.This concept concerns prevention of disease,promotion of a healthy lifestyle and improvement of factors potentially harmful to the health of entire populations.The current"health-in-all-policies" reforms in China may advance the global evidence base for the prevention of chronic disease in low-,middle-and high-income countries.

Confinement to the home and psychological distress due to the coronavirus disease 2019 (COVID-19) pandemic may lead to harmful health behaviors, such as overeating, sedentary behavior with reduced physical activity, elevated alcohol and tobacco use and increased screen time causing impaired sleep. All of these behaviors are associated with non-communicable diseases and can interfere with immunity. While no foods, single nutrients or dietary supplements are capable of preventing infection with COVID-19, a balanced diet containing sufficient amounts of macronutrients and diverse micronutrients is a prerequisite of an optimally functioning immune system. High-energy "Western" diets and obesity are major risk factors for a more severe course of COVID-19. Alcohol use and tobacco also have detrimental effects on the immune system. Therefore, population-wide body weight control, reduction of smoking rates and limitation of alcohol consumption are important preventive measures. Furthermore, sufficient restorative sleep is needed for adequate immune functioning. Appropriate lifestyle changes in regard to nutrition, exercise, sleep, smoking and alcohol intake may help shift the population distribution of infection risk and aid in preventing severe COVID-19 disease. Large-scale surveys should explore the effects of lifestyle changes, and the provision of reliable lifestyle information and effective interventions to individuals and communities during the pandemic is a pressing need.