Purpose
This study investigated the prevalence of
Chlamydia trachomatis
infection, co-infection with Human Papillomavirus (HPV) and associated risk factors in a cohort of sexually active young women ...enrolled in an ongoing trial on HPV vaccination at the European Institute of Oncology (IEO, Milan, Italy).
Methods
Cervical samples were collected from 591 girls (median age 18.8 years) at the beginning of their sexual activity. At the time of sample collection, 354 women had not yet been vaccinated, and 237 women had been vaccinated for at least 12 months. All samples were analyzed through a molecular assay for the detection of
C. trachomatis
infection. Demographic, behavioral risk factors and high-risk HPV (HR-HPV) status were investigated.
Results
The prevalence of
C. trachomatis
infection was 4.9 % and HPV/
C. trachomatis
co-infection rate was 1.5 %. The exact analysis has not underlined statistical significance for the variables considered, except for the infection with HR-HPV (
p
< 0.001). The prevalence of
C. trachomatis
infection among women who had not been immunized and those already vaccinated was similar (5.6 vs 3.8 %). However, the rate of HPV/
C. trachomatis
co-infection was twice as high in unvaccinated women (2 %) compared to vaccinated women (0.8 %).
Conclusions
Over 16 % of young women had at least one of the two STIs investigated. The risk of
C. trachomatis
infection was higher in HR-HPV infected compared to HR-HPV uninfected young women. The rate of co-infection was halved in HPV-vaccinated compared to unvaccinated women. This study underlines that HPV vaccination can confer benefits also in terms of co-infections prevention, leading to a decreased risk of developing cervical malignancies.
Little is known about the epidemiology of human papillomavirus (HPV) in Italy before the age of 25. At the European Institute of Oncology, a prospective observational study on cervical HPV infection ...in 18-year-old women undergoing quadrivalent HPV vaccination is ongoing.
At the first visit before vaccination, all the young women answered an epidemiological questionnaire, and then, the presence of high-risk HPV (hrHPV) was tested. Samples positive for hrHPV were genotyped. Liquid-based cytology was done only to women declaring not to be virgins. Any positivity at cytology or HPV testing was completed with colposcopy and eventually biopsies.
Seven hundred and thirty women were enrolled. Two hundred sixty-six women were virgins; 7 (2.6%) of these resulted positive to hrHPV: 1 had HPV16 and CP6108, whereas the other 6 resulted negative at genotyping. Of the 464 nonvirgins, 61 (13.1%) were HPV positive: 19 had HPV16, 4 were positive to HPV18 with other hrHPVs, 25 to other hrHPVs, 7 to low-risk HPV, whereas 13 resulted negative at genotyping. HPV positivity was significantly associated to both smoking and having more than 3 partners. Cervical cytology was negative in 433 cases (93.3%), ASC-US in 10 cases (2.2%), low-grade squamous intraepithelial lesion in 20 cases (4.3%), and ASC-H in 1 case (0.2%). No CIN2+ was identified.
Overall, we found a low positivity to HPV in this population; however, the rate of HPV positivity was significantly related to smoking and sexual life. The cytology result low-grade squamous intraepithelial lesion was more frequent than in the screening population, whereas no CIN2+ was identified, confirming the indication to avoid screening at this age.
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