Human Papillomavirus (HPV) type 16 and type 18 DNA Loads at Baseline and Persistence of Type-Specific Infection during a 2-year follow-up.
BACKGROUND
Studies of viral load-associated persistence of human papillomavirus (HPV) infection are rare, with inconsistent results reported.


METHODS
The study subjects were 741 and 289 women who were positive for HPV type 16 (HPV-16) and HPV type 18 (HPV-18), respectively, at the time of enrollment into in the ASCUS-LSIL (Atypical Squamous Cells of Undetermined Significance-Low-Grade Squamous Intraepithelial Lesion) Triage Study and who returned 1 or more times for HPV testing during a biannual 2-year follow-up. The numbers of HPV-16 and HPV-18 copies per nanogram of cellular DNA at baseline were measured by use of real-time polymerase chain reaction.


RESULTS
Women with, compared with women without, persistent infection at month 6 of follow-up had a higher viral load at enrollment (P< .001, for HPV-16; P=.01, for HPV-18). The association of each 1-log(10) increase in viral load with persistence of HPV-16 or HPV-18 during the first 6 months of the study was statistically significant among women with multiple HPV types at enrollment (for HPV-16: odds ratio [OR], 1.53 [95% confidence interval {CI}, 1.29-1.82]; for HPV-18: OR, 1.35 [95% CI, 1.09-1.68]) but not among women with monotype infections (in tests assessing the interaction between viral load and coinfection, P=.002 for HPV-16 and P=.34 for HPV-18). Among women who continued to have positive results at month 6, 12, or 18, persistence of infection for another 6 months was unassociated with the viral load at baseline.


CONCLUSIONS
Prevalent infection with a higher viral load of HPV-16 or HPV-18 was associated with short- but not long-term persistence.
Department of Pathology, School of Medicine, University of Washington, Seattle, USA. longfu@u.washington.edu
Long Fu
LF
Xi
James P
JP
Hughes
Zoe R
ZR
Edelstein
Nancy B
NB
Kiviat
Laura A
LA
Koutsky
Constance
C
Mao
Jesse
J
Ho
Mark
M
Schiffman
D000293:Adolescent; D000328:Adult; D016009:Chi-Square Distribution; D004279:DNA, Viral / Q000032:analysis*; D005260:Female; D005500:Follow-Up Studies; D052162:Human papillomavirus 16 / Q000235:genetics*; D052161:Human papillomavirus 18 / Q000235:genetics*; D006801:Humans; D016014:Linear Models; D016015:Logistic Models; D030361:Papillomavirus Infections / Q000473:pathology / Q000821:virology*; D002577:Uterine Cervical Diseases / Q000473:pathology / Q000821:virology*; D002583:Uterine Cervical Neoplasms / Q000473:pathology / Q000821:virology; D019562:Viral Load
D004279:DNA, Viral