Bogaards JA, Coupe VMH, Xiridou M, et al. Long-term impact of human papillomavirus vaccination on infection rates, cervical abnormalities, and cancer incidence. Epidemiology. 2011;22;505–515.
In the Appendix of the paper “Long-term Impact of Human Papillomavirus Vaccination on Infection Rates, Cervical Abnormalities, and Cancer Incidence,” the formula for the lifetime risk of infection was given by (page 7 of the eAppendix, http://links.lww.com/EDE/A484):
This formula makes no correction for the probability of remaining virgin up to age a, and is valid only for those who initiate sexual activity at the model starting age of 10 years. The lifetime infection risk will be much lower for the average woman, and should be calculated as:
Consequently, the numbers reported in the Abstract should read:
At 50% vaccine coverage, the estimated lifetime infection risk in nonvaccinated women dropped from 0.46 (95% credible interval = 0.35–0.54) to 0.37 (0.26–0.46) for HPV-16, and from 0.40 (0.32–0.46) to 0.31 (0.22–0.36) for HPV-18.
The second paragraph of the Results section should start with:
A woman's mean lifetime probability of infection in the prevaccine era is estimated to be 0.46 for type 16 and 0.40 for type 18.
The final sentences of this paragraph should read:
At 50% vaccine coverage, the probability of ever becoming infected with HPV-16 for nonvaccinated women drops from a median of 0.47 (95% CI = 0.35–0.54) to 0.38 (0.26–0.46). For HPV-18, the decline is from a median of 0.41 (0.32–0.46) to 0.31 (0.22–0.36). At 90% vaccine coverage, the lifetime infection risk in nonvaccinated women ultimately drops to 0.10 for HPV-16 (0.02–0.16) and to 0.05 for HPV-18 (0.001–0.10).