In August, a 10-year follow-up study evaluating the long-term efficacy and immunopersistence of the E. coli-produced HPV-16/18 bivalent vaccine (Cecolin) has been published in The Lancet Regional Health - Western Pacific (2025;61:101668), with full text available at https://doi.org/10.1016/j.lanwpc.2025.101668. This observational extension study builds on a pivotal Phase III randomized controlled trial (NCT01735006) to provide evidence of sustained protection over a median follow-up period of 10.2 years, reinforcing the vaccine’s role in long-term cervical cancer prevention.

Cervical cancer remains a global health burden, with HPV 16 and 18 responsible for approximately 70% of cases worldwide. As part of efforts to advance the WHO’s Global Strategy for the Elimination of Cervical Cancer, this 10-year efficacy data strengthens the evidence for cost-effective HPV vaccines, particularly those leveraging E. coli expression systems—known for scalability and affordability—to address vaccine access inequities in resource-limited regions.

Key findings from the 10-year follow-up study:

l Durable efficacy against high-grade lesions and persistent infections

In the per-protocol population (PPS), the vaccine demonstrated 87.5% (95% CI 6.4–99.7) efficacy against high-grade cervical, vulvar, or vaginal lesions (CIN2+, VIN2+, VaIN2+) associated with HPV 16/18, with only 1 case in the vaccine group versus 8 in the control group. This “breakthrough” case of HPV-16 related CIN2 in the HPV vaccine group coupled with complex history of HPV infections, it is probable that HPV 53 instead of HPV 16 caused this lesion.

For persistent HPV 16/18 infections (≥6 months), efficacy reached 97.0% (95% CI 78.9–100.0), with 1 case in the vaccine group versus 32 in the control group.

l Sustained immune responses over a decade

Neutralizing antibody levels peaked at 7 months post-vaccination, declined through month 42, with HPV-16 plateauing and HPV-18 continuing to decline thereafter. At 114 months (9.5 years), 98.9% of participants remained seropositive for HPV 16 (geometric mean concentration [GMC] 61.84 IU/mL) and 97.0% for HPV 18 (GMC 18.73 IU/mL), confirming long-term immunopersistence.

l Consistent protection across age groups

The vaccine showed high efficacy in both women aged 18–26 years (100% against high-grade lesions, 91.6% against persistent infections over 6 months) and 27–45 years (75.3% against high-grade lesions, 100.0% against persistent infections over 6 months), indicating that older women can also benefit from vaccination.

l Time-dependent efficacy in real-world settings

In the intention-to-treat (ITT) population, efficacy increased over time: from 14.5% at 0–36 months to 100.0% at 108–136 months for high-grade lesions, from 68.4% to 100.0% for persistent infections lasting over 6 months, and from 65.5% to 100.0% for incident infections, reflecting the gradual clearance of prevalent infections and sustained prevention of incident infections.

About the Ten-Year Follow-Up Study (NCT05045755, NCT04969445)

This extension study enrolled 1,648 participants (806 in the vaccine group, 842 in the control group) from two sites of the original Phase III trial (Xinmi City and Fengning County, China). Participants received three doses of the HPV vaccine or a hepatitis E control vaccine (0, 1, 6 months schedule). Long-term follow-up included regular cervical cytology, HPV DNA testing, and serum antibody monitoring. The primary endpoints were high-grade lesions and persistent infections associated with HPV 16/18, analyzed in the PPS, modified ITT, and ITT populations.

The study adhered to Good Clinical Practice guidelines and received ethical approval from independent committees. Neutralizing antibodies were measured using a pseudovirion-based neutralization assay (PBNA) with international standards, ensuring consistent and reliable results.

About Cecolin (Recombinant Human Papillomavirus Bivalent (Types 16,18) Vaccine(Escherichia coli) )

Launched in China in 2019, Cecolin is the world's second HPV bivalent vaccine and the first WHO prequalified HPV vaccine from China. As of August 2025, Cecolin has been licensed in 23 countries including 3 PIC/S GMP countries (Thailand, Indonesia, Mexico) and introduced into the National immunization program of 9 countries. With over 70 million doses distributed globally, reported adverse events following immunization (AEFI) have been predominantly mild reactions, confirming its excellent safety profile with no new safety concerns identified.

The vaccine is administered as a 3-dose regimen (0, 1, 6 months) for women aged 15–45 years, with a 2-dose schedule (0, 6 months) recommended for girls aged 9–14 years. Stored at 2–8°C with a 36-month shelf life, it offers logistical advantages for global distribution.

Implications for Global Health

This decade-long efficacy data confirms that E. coli-produced HPV vaccines offer lasting protection, reinforcing their importance in broadening cervical cancer prevention efforts. The study further substantiates the evidence supporting WHO’s cervical cancer elimination strategy by demonstrating sustained efficacy and immune persistence—especially in regions most in need of afordable, high-quality vaccines.

For more information, refer to the full study in The Lancet Regional Health - Western Pacific or visit relevant research institutions’ websites.

About the Collaboration Between Innovax and Xiamen University

Innovax and Xiamen University have established a long-term strategic partnership in HPV vaccine research and development, combining Innovax's expertise in recombinant vaccine manufacturing with Xiamen University's strength in infectious disease research. This collaboration has led to the successful development of Cecolin (HPV bivalent vaccine, WHO-prequalified) and Cecolin 9 (HPV 9-valent vaccine), with a shared mission to advance affordable, high-quality HPV vaccines for global public health.

About Innovax

As one of the leading vaccine manufacturers in China, Xiamen Innovax Biotech Co., Ltd. (Innovax) was founded in 2005 and has been dedicated to human vaccine development, manufacturing and commercialization for nearly 20 years. As a wholly owned subsidiary of Beijing Wantai Biological Pharmacy Enterprise Co., Ltd. (Wantai BioPharm), a public listed company in China (Stock Code: 603392), Innovax's mission is to provide high-quality and affordable vaccines to improve human well-being.

Innovax has developed a unique recombinant virus-like particle (VLP) vaccine platform* based on Escherichia coli, leveraging this cutting-edge technology to successfully launched the world's first recombinant hepatitis E vaccine (Hecolin) and the world's second HPV bivalent vaccine(Cecolin). In 2025, Innovax's HPV 9-valent vaccine (Cecolin 9) has been approved in China, which is the world's second HPV 9-valent Vaccine. Innovax never stops advancing in innovation for life.

For more information, please visit Innovax's official website: https://www.innovax.cn/en/ and follow us on LinkedIn (@Xiamen Innovax Biotech Co., Ltd) .

*The technology platform is co-developed by Innovax and Xiamen University.