Joe Biden flips Arizona as Trump keeps transition in limbo, Chicago and Detroit told to hunker down as pandemic surges, and things to know about Friday the 13th.
There are over 35,000,000 reported cases of COVID-19 disease and 1 000 000 deaths across more than 200 countries worldwide.1 With cases continuing to rise and a robust vaccine not yet available for safe and widespread delivery, lifestyle adaptations will be needed for the foreseeable future. As we try to contain the spread of the virus, adults are spending more time at home. Recent evidence2 suggests that physical activity levels have decreased by ~30% and sitting time has increased by ~30%. This is a major concern as physical inactivity and sedentary behaviour are risk factors3 for cardiovascular disease, obesity, cancer, diabetes, hypertension, bone and joint disease, depression and premature death.
To date, more than 130 authors from across the world have provided COVID-19-related commentary on these concerns. Many experts4 have emphasised the importance of increasing healthy living behaviours and others5 have indicated that we are now simultaneously fighting not one but two pandemics (ie, COVID-19, physical inactivity). Physical inactivity alone results in over 3 million deaths per year5 and a global burden of US$50 billion.6 Immediate action is required to facilitate physical activity during the COVID-19 pandemic because it is an effective form of medicine3 to promote good health, prevent disease and bolster immune function. Accordingly, widespread messaging to keep adults physically active is of paramount importance.
Several organisations including the WHO, American Heart Association and American College of Sports Medicine have offered initial suggestions and resources for engaging in physical activity during the COVID-19 pandemic. Expanding on these resources, our infographic aims to present a comprehensive illustration for promoting daily physical activity to the lay audience during the COVID-19 pandemic (figure 1). As illustrated, adults are spending more time at home, moving less and sitting more. Physical activity provides numerous health benefits, some of which may even help directly combat the effects of COVID-19. For substantial health benefits, adults should engage in 150–300 min of moderate-to-vigorous intensity physical activity each week and limit the time spent sitting. The recommended levels of physical activity are safely attainable even at home. Using a combination of both formal and informal activities, 150 min can be reached during the week with frequent sessions of physical activity spread throughout the day. Sedentary behaviour can be further reduced by breaking up prolonged sitting with short active breaks. In summary, this infographic offers as an evidence-based tool for public health officials, clinicians, educators and policymakers to communicate the importance of engaging in physical activity during the COVID-19 pandemic.
What Is Herd Immunity?
Herd immunity occurs when a significant portion of a population becomes immune to an infectious disease, limiting further disease spread.
Disease spread occurs when some proportion of a population is susceptible to the disease. Herd immunity occurs when a significant portion of a population becomes immune to an infectious disease and the risk of spread from person to person decreases; those who are not immune are indirectly protected because ongoing disease spread is very small.
The proportion of a population who must be immune to achieve herd immunity varies by disease. For example, a disease that is very contagious, such as measles, requires more than 95% of the population to be immune to stop sustained disease transmission and achieve herd immunity.
How Is Herd Immunity Achieved?
Herd immunity may be achieved either through infection and recovery or by vaccination. Vaccination creates immunity without having to contract a disease. Herd immunity also protects those who are unable to be vaccinated, such as newborns and immunocompromised people, because the disease spread within the population is very limited. Communities with lower vaccine coverage may have outbreaks of vaccine-preventable diseases because the proportion of people who are vaccinated is below the necessary herd immunity threshold. In addition, the protection offered by vaccines may wane over time, requiring repeat vaccination.
Achieving herd immunity through infection relies on enough people being infected with the disease and recovering from it, during which they develop antibodies against future infection. In some situations, even if a large proportion of adults have developed immunity after prior infection, the disease may still circulate among children. In addition, antibodies from a prior infection may only provide protection for a limited duration.
People who do not have immunity to a disease may still contract an infectious disease and have severe consequences of that disease even when herd immunity is very high. Herd immunity reduces the risk of getting a disease but does not prevent it for nonimmune people.
Herd Immunity and COVID-19
There is no effective vaccine against coronavirus disease 2019 (COVID-19) yet, although several are currently in development. It is not yet known if having this disease confers immunity to future infection, and if so, for how long. A large proportion of people would likely need to be infected and recover to achieve herd immunity; however, this situation could overwhelm the health care system and lead to many deaths and complications. To prevent disease transmission, keep distance between yourself and others, wash your hands often with soap and water or sanitizer that contains at least 60% alcohol, and wear a face covering in public spaces where it is difficult to avoid close contact with others.