Governments around the world must rapidly mobilize and make difficult policy decisions to mitigate the coronavirus disease 2019 (COVID-19) pandemic. Because deaths have been concentrated at older ages, we highlight the important role of demography, particularly, how the age structure of a population may help explain differences in fatality rates across countries and how transmission unfolds. We examine the role of age structure in deaths thus far in Italy and South Korea and illustrate how the pandemic could unfold in populations with similar population sizes but different age structures, showing a dramatically higher burden of mortality in countries with older versus younger populations. This powerful interaction of demography and current age-specific mortality for COVID-19 suggests that social distancing and other policies to slow transmission should consider the age composition of local and national contexts as well as intergenerational interactions. We also call for countries to provide case and fatality data disaggregated by age and sex to improve real-time targeted forecasting of hospitalization and critical care needs.

Governments around the world must rapidly mobilize and make difficult policy decisions to mitigate the COVID-19 pandemic. Because deaths have been concentrated at older ages, we highlight the important role of demography, particularly how the age structure of a population may help explain differences in fatality rates across countries and how transmission unfolds. We examine the role of age structure in deaths thus far in Italy and South Korea and illustrate how the pandemic could unfold in populations with similar population sizes but different age structures, showing a dramatically higher burden of mortality in countries with older versus younger populations. This powerful interaction of demography and current age-specific mortality for COVID-19 suggests that social distancing and other policies to slow transmission should consider both the age composition of local and national contexts as well as the social connectedness of older and younger generations. We also call for countries to provide case and fatality data disaggregated by age and sex to improve real-time targeted nowcasting. BackgroundGovernments are rapidly mobilizing to minimize transmission of COVID-19 through social distancing and travel restrictions to reduce fatalities and the outstripping of healthcare capacity. It is becoming clear that the pandemic's progression and impact may be strongly related to the demographic composition of the population, specifically population age structure. Demographic science can provide new insights into how the pandemic may unfold and the intensity and type of measures needed to slow it down.Currently, COVID-19 mortality risk is highly concentrated at older ages, particularly those aged 80+. In China, case-fatality rate (CFR) estimates range from 0.4% (40-49 years), jumping to 14.8% (80+ years).(1) This is consistent with the data from Italy as of March 16, where the reported CFR is 11.8% for those 70-79, 18.8% for 80-89, and 21.6% for those >90. Thus far in Italy, only 1.5% of deaths have occurred in those under aged 60.(2) As testing becomes more widespread, these case fatality rates may come down due to an increase in the true denominator. Nonetheless, in South Korea where testing was broader and the health system not overtaxed, the current CFR for those 80+ is still an alarming 9.26%. (7) The Importance of Age Structure Population age structure may explain the remarkable variation in fatalities across countries and why countries such as Italy are especially vulnerable. The deluge of critical and fatal COVID-19 cases in Italy was unexpected given the health and wealth of the affected region. Italy is one of the oldest populations in the world with 23.3% its population over age 65, compared to 12% in China (3). Italy is also a country characterized by extensive intergenerational contacts which are supported by a high degree of residential proximity between adult children and their parents (4). Even when inter-generational families do not live together, daily contacts among non-co-resident parent-child pairs are...

This study provides new evidence on how the growingly significant digital life shapes Chinese adolescents' cognitive and mental health outcomes based on their gender, parental education, and geographical location. Using the China Education Panel Survey, a nationally representative survey following 12-15-year-old students in 2013 and 2014, and individual fixed-effect models, we find that more time spent on the Internet is associated with higher selfreported depression scores. This negative impact on mental health is more substantial for girls, those with lesseducated parents, and those living outside the city center. The link between Internet use and cognitive development is almost null. Time spent online negatively affects Chinese young adolescents' subjective well-being but has little impact on their cognitive development. The link between Internet use time and subjective well-being also depends on gender, parental education, and the geographical location of those adolescents. The heterogeneous impacts of Internet use time offer crucial new evidence to the multiple dimensions of the digital divide among adolescents in China.