Kristen Rozansky, Vice Dean for External Relations at Harvard T.H. Chan School of Public Health, said the Delta variant poses the biggest threat, especially in regions with low vaccination rates.
He said many parts of the world are still in the thick of COVID-19, while others are grappling with its ripple effects, adding that whether one is at the epicenter of this pandemic or on the periphery, the world is interconnected and everyone matters.

Bill Hanage, associate professor of epidemiology, said, “Every mutation buys the virus a lottery ticket. Sometimes that lottery ticket comes up with a mutation which enables it to transmit to more people.” He recommends that even for vaccinated people, “If you are in a place where cases are climbing, wearing a mask indoors in crowded public spaces is a way to keep yourself from contributing to the spread.”
In addition, long COVID patients—those still suffering from debilitating symptoms well after being infected—are unfortunately, “the next public health disaster in the making,” said Dean Michelle Williams in a recent co-authored article. “Though data are still emerging, the average age of patients with long COVID is about 40, which means that the majority are in their prime working years. Given these demographics, long COVID is likely to cast a long shadow on our health care system and economic recovery.”
Another ripple effect of the pandemic is a surge in risky behavior among Americans as COVID-19 upended the economy, swelled unemployment rolls, and caused social disconnection. This includes increased fast-food consumption, drug, alcohol, and cigarette use, and gun violence. According to Michael Barnett, assistant professor of health policy and management, “Economic, mental, and social distress are all a perfect set of ingredients to foment addiction.”
Caroline Buckee, professor of epidemiology and associate director of the Center for Communicable Disease Dynamics, reminds us, “Social and cultural forces shape almost every aspect of infectious disease transmission in human populations, as well as our ability to measure, understand, and respond to epidemics. One of the most important lessons of the pandemic so far is that the central forces shaping local and global variation in disease burden and dynamics have been social, not biological.”