"If children from ages 5 to 17 are as or possibly even more contagious than adults, then opening schools in areas where daily rates of infection remain moderate to high is extremely risky and unwise. The measures we deploy to contain the spread of Covid-19 in our schools and our communities must take the entire population into account—children age 18 and below included". William A. Haseltine, professor at Harvard Medical School and Harvard School of Public Health.