Letter to the editor: female sex workers and HPV vaccine.

When considering what the scientific evidence is for the potential added value to offer HPV vaccines to sex workers, not only its potential role for female sex workers should be examined, but its role for all those who conduct sex work. Our initial paper looked at the evidence in terms of HPV vaccine immunogenicity, efficacy, effect on transmission, induction of mucosal immunity, and not at implementation. Brown and Cabral considered our omission to address the aspects of implementation an 'academic mistake'. We disagree; implementation aspects are complex and require analyses of multiple barriers, and how to address these. It only makes sense to discuss these if there is scientific evidence for its implementation; otherwise offering the vaccine is not useful.