Young- and middle-aged people in the United States spread the coronavirus the most and are the main source of the pandemic, while the infection mostly kills older people.
According to a new study published in the journal Science, American adults ages 20-49 were responsible for the vast majority of COVID-19 transmission last year. Millions more Americans could be infected before a significant portion of the population is vaccinated, making transmission patterns very relevant.
The notion that invulnerable people can lead normal lives while vulnerable people are self-isolated has not been borne out in the United States. Until mid-August of last year, three-quarters of new infections came precisely from adults between the ages of 20 and 49. The biggest contributors to the spread were people between the ages of 35 and 49. Even after most students returned to campuses, this age group still accounted for about 72 percent of new infections.
According to the authors, young and middle-aged people “naturally have the most contact with other adults in their 20s and older who are more susceptible” to the coronavirus.