Other viral vaccines are currently under study; TA-HPV (recombinant Vaccinia virus expressing E6 and E7) was characterized by an acceptable safety profile and immunogenicity in a phase II study [81], TG4001 (recombinant vaccinia virus Ankara containing the sequence coding for E6 and E7 and IL-2) was administered to CIN patients, obtaining mRNA clearance and CIN regression at colposcopy in 70% of cases [82]. This evidence concerns the gene IL2 and cervical squamous intraepithelial neoplasia.