IARC 60th Anniversary - 19-21 May 2026
Session : 20/05/26 - Posters
Immune memory and antibody avidity following a single versus two doses of Escherichia coli-produced vaccine against HPV 16 and 18 in Chinese girls
HU S. 1, WEN T. 1, DONG L. 2, LI J. 3, FENG Y. 1, NIE L. 3, LI Z. 1, ZHANG L. 3, HUANG w. 3, ZHAO F. 1, BASU P. 4
1 National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China; 2 Shanxi University, Institute of Biomedical Sciences, Taiyuan, China; 3 National Institutes for Food and Drug Control , Beijing, China; 4 International Agency For Research On Cancer, Lyon, France
Background: Prophylactic human papillomavirus (HPV) vaccines are highlighted by the WHO as a foundational pillar on the path to accelerate the elimination of cervical cancer. A single dose of the HPV vaccine could substantially reduce costs and simplify implementation of national HPV immunization programs. However, a comprehensive profile of immunogenicity induced by a single dose has yet to be presented.
Objectives: We report data from the interim analysis of an ongoing real-world non-interventional study, which aims to compare the immune memory and antibody responses of a single and two doses of the Escherichia coli-produced HPV-16/18 vaccine in Chinese girls.
Methods: Girls aged 9–14 years who received a single or two doses of the E. coli-produced HPV-16/18 vaccine were enrolled and followed at 12 months. HPV-16/18-specific neutralizing antibodies, IgG antibodies, and memory B- and T-cell responses were assessed and compared between the single-dose and two-dose groups.
Results: Among 492 per-protocol participants (298 two-dose; 194 single-dose), the median follow-up was 12.07 months. Single-dose neutralizing antibody seropositivity exceeded 90% for HPV-16 and approached 80% for HPV-18. The geometric mean avidity index of HPV-16 IgG after a single dose was non-inferior to that after two doses (lower bound of the geometric mean avidity ratio > 0.5). Both dosing schedules induced HPV-16/18-specific memory B- and T-cell responses with similar positivity and geometric means (p > 0.05).
Conclusions: A single dose of the E. coli-produced HPV-16/18 vaccine elicits robust antibody quantity and quality, with immune memory comparable to two doses in girls aged 9–14 years, supporting its potential in population application and contribution to the WHO's cervical elimination target of vaccinating 90% of girls.