Young and middle-aged adults are responsible for most of the spread of COVID in the United States

The coronavirus pandemic in the United States has been primarily led by young and middle-aged people, while primarily killing the elderly.

Driving the news: Adults between the ages of 20 and 49 were responsible for the vast majority of transmission of the virus last year, even after schools reopened in the fall, according to a new study published in Science.

Why is this important: The US vaccination effort is rushing to track the spread of new, more transmissible variants of the virus. Millions more Americans could be infected before a substantial portion of the population is vaccinated, making transmission patterns deeply relevant.

• The idea that non-vulnerable people can lead their normal lives, while vulnerable people isolate themselves, has not been borne out in the United States.

In numbers: Three-quarters of new infections were from adults aged 20 to 49 until mid-August last year. Adults aged 35 to 49 contributed the most to the spread.

• In October, after a large chunk of American students returned to school, this age group was still responsible about 72% of new infections.
• The study estimates that reopening schools increased total infections by around 26% in October and deaths by around 6% – because children and adolescents transmit the virus to adults, who are “more efficient at it. transmission ”.

Between the lines: Young and middle-aged adults “naturally have most contact with other adults aged 20 and over, who are more susceptible” to the virus, and they were more mobile from April, according to the study .

The bottom line: “This suggests that additional interventions with adults aged 20 to 49, including rapid mass vaccination if vaccines are found to block transmission, could contain the resurgence of COVID-19 epidemics,” the authors conclude.