How does Delta complicate the equation?
Roughly twice as transmissible as the original version of the virus, Delta has fueled a rise in infections and hospitalizations, especially in areas of the country where vaccination rates are low. Recent data suggests that people who are infected with Delta may carry a thousand times as much virus — which could make them more contagious and for longer — as those who catch the original version of the virus.
But many questions about the variant remain unanswered, including the precise risk it poses in a school setting. What is clear, however, is that Delta is already driving outbreaks in many American communities, which raises the risks for local schools.
“Schools are not islands and so if there’s a lot of community spread some of that spread is going to spill over into schools,” said Dr. Westyn Branch-Elliman, an infectious-disease specialist at Harvard Medical School.
In a study conducted before Delta was widespread, British researchers found that for every five additional cases per 100,000 people in a community at large, the risk of a school outbreak increased 72 percent.
The good news is that since the last school year started, the United States has authorized three highly effective vaccines for emergency use, and they are widely available to those 12 and older.
The vaccines are not flawless. Some fully vaccinated people will get breakthrough infections, which are generally mild and rare. And those vaccinated people who are infected with Delta can carry high levels of the virus in their noses and throats, which means they may be able to readily transmit it.