As more people become fully vaccinated, some are wondering why public health officials are still recommending wearing masks and practicing physical distancing. As part of Penn State’s “COVID-19 Vaccines: Asked & Answered,” Moriah Szpara, associate professor of biology and biochemistry and molecular biology, explains that data show that the COVID-19 vaccines are excellent at protecting against the most severe outcomes of COVID-19, but they may not prevent you from acquiring an infection and potentially spreading the disease to others.