Despite the act that it ends in s, it is one disease.
To determine the correct verb form in this sentence, you need to understand subject-verb agreement. In this case, the subject is "Shingles," which refers to a disease. Since "shingles" is a singular noun, the correct verb form is "affects," which matches the singular subject. Therefore, the correct sentence is "Shingles affects 1 out of 3 people in the United States."
