Frequency and risk factors for prevalent, incident, and persistent genital carcinogenic human papillomavirus infection in sexually active women: community based cohort study.
OBJECTIVE
To investigate frequency and risk factors for prevalent, incident, and persistent carcinogenic human papillomavirus (HPV) in young women before the introduction of immunisation against HPV types 16 and 18 for schoolgirls.


METHODS
Cohort study


METHODS
20 London universities and further education colleges.


METHODS
2185 sexually active female students, mean age 21 years (range 16-27), 38% from ethnic minorities, who took part in the POPI (prevention of pelvic infection) chlamydia screening trial in 2004-08 and who provided duplicate, self taken vaginal swabs and completed questionnaires at baseline. At follow-up, a median of 16 months later, 821 women (38%) returned repeat vaginal swabs by post. In 2009-10, stored samples were tested for HPV.


RESULTS
Samples from 404/2185 (18.5% (95% CI 16.9% to 20.2%)) of the cohort were positive for carcinogenic HPV at baseline, including 15.0% (327) positive for non-vaccine carcinogenic genotypes. Reporting two or more sexual partners in the previous year and concurrent Chlamydia trachomatis or bacterial vaginosis were independent risk factors for prevalent vaginal HPV infection. Infection with one or more new HPV types was found in 17.7% (145/821) of follow-up samples, giving an estimated annual incidence of carcinogenic HPV infection of 12.9% (95% CI 11.0% to 15.0%). Incident infection was more common in women reporting two or more partners in the previous year, aged<20, of black ethnicity, or  with C trachomatis vaginosis at baseline. Multiple partners was the only independent risk factor for incident infection (adjusted relative risk 1.99 (95% CI 1.46 to 2.72)). Of 143 women with baseline carcinogenic HPV infection, 20 (14% (8.3% to 19.7%) had infection with the same carcinogenic HPV type(s) detected after 12-28 months. Of these women, 13 (65%) had redetected infection with HPV 16 or 18, and nine (45%) with non-vaccine carcinogenic HPV genotypes.


CONCLUSIONS
In the first UK cohort study of carcinogenic HPV in young women in the community, multiple sexual partners was an independent predictor of both prevalent and incident infection. Infection with non-vaccine carcinogenic genotypes was common. Although current HPV vaccines offer partial cross protection against some non-vaccine carcinogenic HPV types, immunised women will still need cervical screening.
Division of Population Health Sciences, St George's, University of London SW17 0RE, UK. p.oakeshott@sgul.ac.uk
Pippa
P
Oakeshott
Adamma
A
Aghaizu
Fiona
F
Reid
Rebecca
R
Howell-Jones
Phillip E
PE
Hay
S Tariq
ST
Sadiq
Charles J
CJ
Lacey
Simon
S
Beddows
Kate
K
Soldan
D000293:Adolescent; D000328:Adult; D002690:Chlamydia Infections / Q000453:epidemiology; D002692:Chlamydia trachomatis; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D052162:Human papillomavirus 16; D052161:Human papillomavirus 18; D006801:Humans; D015994:Incidence; D008131:London / Q000453:epidemiology; D027383:Papillomaviridae; D030361:Papillomavirus Infections / Q000453:epidemiology* / Q000208:ethnology; D015995:Prevalence; D060737:Reproductive Tract Infections / Q000453:epidemiology* / Q000208:ethnology; D012307:Risk Factors; D012725:Sexual Behavior / Q000706:statistics & numerical data; D012747:Sexual Partners; D012749:Sexually Transmitted Diseases / Q000453:epidemiology* / Q000208:ethnology; D002583:Uterine Cervical Neoplasms / Q000208:ethnology / Q000209:etiology*; D016585:Vaginosis, Bacterial / Q000453:epidemiology