Predicted impact of HPV vaccination and primary HPV screening on precancer treatment rates and adverse pregnancy outcomes in Australia 2010–2070: Modelling in a high income, high vaccination coverage country with HPV-based cervical screening

Abstract

Background

Treatment of cervical precancer may be associated with an increased risk of adverse pregnancy outcomes. Australia introduced routine quadrivalent HPV vaccination (HPV4) in 2007, switching to nonavalent vaccination (HPV9) in 2018, and 5-yearly HPV screening in December 2017. We estimated the impact of HPV vaccination and HPV screening on precancer treatments, and thus on future preterm births (PTBs) and low birth weight (LBW) infants.

Methods

Using a model of HPV infection, natural history, cervical screening and precancer treatment, coupled with a Monte-Carlo model of fertility and obstetric outcomes, we estimated rates and numbers of precancer cervical treatments, PTBs and LBW infants in women with singleton pregnancies in Australia from 2010 to 2070. These outcomes were estimated for four scenarios: i) a base scenario, assuming the current HPV screening and vaccination programs; and three alternative scenarios: ii) future twice-lifetime screening in cohorts offered HPV9; (iii) no HPV vaccination program introduced (counterfactual); and (iv) HPV4 was never replaced with HPV9 (counterfactual).

Results

Precancer treatment rates are predicted to decrease by 82 % between 2010 and 2070 in the context of HPV9 vaccination and ongoing 5-yearly screening, with an additional 42 % reduction by changing to twice-lifetime screening in HPV9 cohorts. An estimated 800,388 treatments would be averted over 2010–2070 by HPV9 compared to no vaccination, 80 % of these due to vaccine protection against HPV16/18. These treatment reductions will result in 22,441 (32,011) fewer PTBs (LBW infants) over 2010–2070 due to vaccine protection against HPV16/18, and a further 4359 (6298) due to vaccine protection against HPV31/33/45/52/58. An additional 3174 (4621) events would be averted with future twice-lifetime screening in HPV9 cohorts.

Conclusion

This analysis demonstrates that the benefits of HPV vaccination programs extend beyond prevention of HPV-related disease. HPV vaccination will reduce PTBs and LBW infants, with a further reduction with future twice-lifetime screening for HPV9 cohorts.