How has post-implementation surveillance of high-coverage vaccination with HPV16/18-AS04 vaccine in England added to evidence about its cross-protective effects?

BACKGROUND

Bivalent human papillomavirus HPV16/18-AS04 vaccine (Cervarix, GSK) offers direct protection against HPV16/18. Results from randomised controlled trials showed cross protective effects and suggested that declines in some closely related HPV types could be expected in a population with high vaccination coverage.

AIM

To evaluate the evidence for cross-protection afforded by HPV16/18-AS04 from post-implementation surveillance in England, and how this complements clinical trial data and post-implementation observations in other countries.

METHODS

Evidence of cross-protection in young women offered vaccination with HPV16/18-AS04 was gathered from HPV surveillance in England. Data from clinical trials and other post-implementation studies were reviewed.

RESULTS

Surveillance using anonymised residual specimens in England found declines of 52.3%, 67.4% and 33.3% against grouped HPV-31/33/45 in 16-18, 19-21, and 22-24 year olds, respectively. Additionally, type-specific analysis found that the prevalence of HPV31 declined to below 1% across all age groups. Cross-protection has been monitored and maintained for over 10 years since the introduction of the vaccination programme. Cross-protection against HPV6/11 was not found in English surveillance outcomes.

CONCLUSION

Surveillance of type-specific infections in vaccine-eligible populations in England has generated clear evidence of cross-protective effects from HPV16/18-AS04 vaccination against high-risk HPV 31/33/45 infections, consistent with other post-implementation observations and confirming and in some ways exceeding expectations from clinical trials.