Presence of HPV in later life may represent reactivation, not reinfectionBMJ 2012; 345 doi: http://dx.doi.org/10.1136/bmj.e8517 (Published 17 December 2012) Cite this as: BMJ 2012;345:e8517
Recurrent human papillomavirus (HPV) infection in women seen around the time of menopause may represent the reactivation of an old infection acquired decades earlier, rather than a new exposure, says a new study.1
Epidemiological studies worldwide have found two peaks of HPV infection in women. The first occurs a few years after sexual debut, followed by clearance of the infection in a significant proportion of women. The incidence during this peak correlates with the number of sexual partners.
The second peak occurs around the time of menopause. There are two main theories as to why this occurs: a new sexual partner or increased numbers of sexual partners; and immunosenescence that allows a latent infection to emerge.
The study, published in the Journal of Infectious Diseases, looked at a cohort of 843 women aged 35-60 years from Baltimore. The women were predominantly white (74%), married (63%), and highly educated. Nearly all the women (90%) had used hormonal contraceptives at some time, but less than a quarter (22%) currently used them. All had a history of a Pap smear test, and half (49%) reported a history of abnormal findings.
The study found that the age specific prevalence of 14 high risk HPV genotypes declined with age among women who had fewer than five lifetime sex partners but not among women with more than five lifetime sex partners (P=0.01). The population attributable risk among women with ≥5 lifetime sex partners was higher in older women (87.2%) than in younger women (28%).
The risk associated with a new partner was 28% among women aged 35-49 and 7.7% among women aged 50-60.
“The relative increase in HPV prevalence between women with high and those with low numbers of lifetime sex partners increased steadily with age, supporting the possibility that HPV reactivation increases at older ages,” wrote Patti Gravitt and colleagues.
If this were true, “prophylactic vaccination would be unlikely to provide significant benefit” in terms of acquisition. However, as the relatively new vaccine for shingles has shown, perhaps vaccination might prevent latent infection from emerging to clinical disease, they say.
“We propose that the cohort effect of the sexual revolution in the United States is masking an increase in HPV prevalence in older age, which may be secondary to reactivation of ‘latent’ infection,” they wrote.
The authors say that there is a clear need for a more sensitive assay to distinguish between true clearance of an initial infection and its suppression to a latent state.
Cite this as: BMJ 2012;345:e8517