Preventing Animal Abuse and Waste Act of 2021 or the PAAW Act of 2021 This bill prohibits the National Institute of Allergy and Infectious Diseases (NIAID) from conducting or supporting research that causes significant pain or distress to a dog. The bill also requires reporting about the use of dogs in research studies. First, the National Institutes of Health must report on ongoing or prospective research conducted or supported by NIAID that causes significant pain or distress to a dog and the amount of funds obligated for such research. Second, NIAID must report on efforts to phase out the use of dogs in the research it conducts or supports.