Seroprevalence and correlates of human papillomavirus 16/18 seropositivity among young women in Costa Rica.
BACKGROUND
Serological indicators of human papillomavirus (HPV) infection are being used to differentiate HPV-naïve from previously infected women in vaccine and epidemiologic/clinical studies. We investigated HPV16 and 18 seroepidemiology among young, unvaccinated women aged between 18 and 25.


METHODS
We conducted a cross-sectional evaluation of the enrollment visit in the ongoing community-based HPV16/18 Costa Rica Vaccine Trial. Prevaccination serum immunoglobulin G (IgG) antibodies were measured against HPV16 and HPV18 by enzyme-linked immunosorbent assay; cervical samples were tested for HPV DNA using Hybrid Capture 2 and SPF10/LiPA25. Seroprevalence and its correlates were evaluated using unconditional logistic regression.


RESULTS
Among 5871 nonvirginal women, HPV16 and 18 seroprevalences were 30.8% and 28.1%, HPV16 and HPV18 DNA prevalences were 8.3% and 3.2%, respectively. About 37% of HPV16 DNA-positives and 42% of HPV18 DNA-positives were seronegative. Seroprevalence increased with time since sexual debut, whereas DNA prevalence did not. The correlates of HPV16 and/or 18 seropositivity were related to sexual behaviors, particularly higher number of lifetime sexual partners. There was no evidence of assay cross-reactivity as HPV16 seroprevalence was similar (approximately 34%) among women singly infected with genetically and nongenetically related species (α9 and non-α9); likewise, seropositivity to HPV18 was similar (approximately 30%) among women singly infected with α7 and non-α7 species.


CONCLUSIONS
The increasing seroprevalence observed with time since first sex suggests that HPV serology is a cumulative marker of HPV exposure. However, many DNA infected women were seronegative; thus, serology is an imperfect measure of past exposure to cervical HPV, at best. Additionally, we found no evidence of assay cross-reactivity.
Coseo
Sarah
S
Infections and Immunoepidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, 6120 Executive Blvd, EPS, Room 7079, Rockville, MD 20852, USA. coseose@mail.nih.gov
Porras
Carolina
C
Hildesheim
Allan
A
Rodriguez
Ana Cecilia
AC
Schiffman
Mark
M
Herrero
Rolando
R
Wacholder
Sholom
S
Gonzalez
Paula
P
Wang
Sophia S
SS
Sherman
Mark E
ME
Jimenez
Silvia
S
Solomon
Diane
D
Bougelet
Catherine
C
van Doorn
Leen-Jan
LJ
Quint
Wim
W
Safaeian
Mahboobeh
M
D000293:Adolescent; D000328:Adult; D000914:Antibodies, Viral / Q000097:blood*; D002584:Cervix Uteri / Q000821:virology; D003364:Costa Rica / Q000453:epidemiology; D003430:Cross-Sectional Studies; D004279:DNA, Viral / Q000032:analysis; D005260:Female; D052162:Human papillomavirus 16 / Q000235:genetics / Q000276:immunology*; D052161:Human papillomavirus 18 / Q000235:genetics / Q000276:immunology*; D006801:Humans; D030361:Papillomavirus Infections / Q000453:epidemiology* / Q000276:immunology / Q000517:prevention & control / Q000821:virology; D053918:Papillomavirus Vaccines / Q000008:administration & dosage / Q000276:immunology; D016036:Seroepidemiologic Studies; D002583:Uterine Cervical Neoplasms / Q000453:epidemiology / Q000821:virology; D016387:Women's Health; D055815:Young Adult
D000914:Antibodies, Viral; D004279:DNA, Viral; D053918:Papillomavirus Vaccines