In Reply Dr Johnson and colleagues raise a good point, as expressed in our article, that our findings should not be inferred to suggest that circulating tumor human papillomavirus (HPV) DNA (ctHPVDNA) is ready to be used for screening. Our observation that no ctHPVDNA was detected in healthy participants with detectable salivary HPV DNA or E6 serum antibody suggests a low false-positive rate (ie, suggests good specificity). However, as pointed out in the discussion of our research letter, and by Johnson et al, it is possible that the detection methods used in our study could be insensitive, and additional research is needed to verify the finding of high specificity in our study.
