Since the early days of the COVID-19 pandemic, there were questions about how people in active cancer treatment would fare if they became infected with SARS-CoV-2. The worries were due, in large part, to the effects that cancer and its treatments can have on the immune system. Now that COVID-19 vaccines are widely available, concerns have shifted to the safety and effectiveness of vaccination in this potentially vulnerable population. A study published June 5 in the journal Cancer Cell aims to allay those fears.