***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND Human papillomavirus ( HPV ) has been associated with cervical intraepithelial neoplasia , but the temporal relation between the infection and the neoplasia remains unclear , as does the relative importance of the specific type of HPV , other sexually transmitted diseases , and other risk factors . METHODS We studied prospect ively a cohort of 241 women who presented for evaluation of sexually transmitted disease and had negative cervical cytologic tests . The women were followed every four months with cytologic and colposcopic examinations of the uterine cervix and tests for HPV DNA and other sexually transmitted diseases . RESULTS Cervical intraepithelial neoplasia grade 2 or 3 was confirmed by biopsy in 28 women . On the basis of survival analysis , the cumulative incidence of cervical intraepithelial neoplasia at two years was 28 percent among women with a positive test for HPV and 3 percent among those without detectable HPV DNA : The risk was highest among those with HPV type 16 or 18 infection ( adjusted relative risk as compared with that in women without HPV infection , 11 ; 95 percent confidence interval , 4.6 to 26 ; attributable risk , 52 percent ) . All 24 cases of cervical intraepithelial neoplasia grade 2 or 3 among HPV-positive women were detected within 24 months after the first positive test for HPV . After adjustment for the presence of HPV infection , the development of cervical intraepithelial neoplasia was also associated with younger age at first intercourse , the presence of serum antibodies to Chlamydia trachomatis , the presence of serum antibodies to cytomegalovirus , and cervical infection with Neisseria gonorrhoeae . CONCLUSIONS Cervical intraepithelial neoplasia is a common and apparently early manifestation of cervical infection by HPV , particularly types 16 and 18 Am J Public Health 2000 90:1431–5 A cross-sectional , door-to-door community survey was used to gather self-report data on Pap smear and cholesterol screening from 195 rural Australian individuals r and omly selected from population statistics . Trained interviewers used a st and ard reporting form to collect information on screening results , knowledge of recommended screening frequency , and demographics . The two regional pathology laboratories were queried about consenting patients . Adequate screening was defined as any smear within 2 years . Of 146 women eligible for validation of Pap smears , the sensitivity of a self-report of inadequate screening was 45 % , the specificity was 98 % , the negative predictive value was 72 % , and the positive predictive value was 93 % . For example , 93 % of women who said they had not had a Pap smear in at least 2 years in fact had not , while only 72 % of those who cl aim ed to have had a smear within 2 years actually had . Among 91 women reporting Pap results , more than half of those with abnormalities were missed by self-report . The accuracy of recall was not associated with knowledge or demographic factors . Comment : Although its use of a rural , Australian population limits the ability to generalize the conclusions of the report for the population in the United States , the results of this study are consistent with those of previous ones : women tend to overestimate the frequency of their Pap smears and to minimize their recall of abnormalities .  Self-report should not be used in studies of the adequacy of Pap smear screening , and it should not be relied on to determine who is eligible for screening at 3-year intervals by virtue of three prior normal smears . ( LSM Objective : To estimate the incidence and duration of cervical human papillomavirus (HPV)-6 , HPV-11 , HPV-16 , and HPV-18 infections in a population of young American women . Methods : The study population consisted of U.S. women who at baseline were 16 to 23 years of age , reported zero to five lifetime sexual partners , never having been pregnant , and never having had a prior abnormal Papanicolaou test and were enrolled in the placebo arm of a r and omized multicenter clinical trial of a HPV-16 L1 virus-like particle vaccine . Women underwent type-specific endocervical/ectocervical swab HPV DNA testing at ∼6-month intervals for up to 48 months of follow-up . To contribute person-time in the analyses of type-specific HPV incidence , a woman must have had at least three satisfactory swab specimens available and been negative for the relevant HPV type ( HPV-6 , HPV-11 , HPV-16 , or HPV-18 ) on her first two trial swabs . The duration of incident HPV infections was estimated using Kaplan-Meier survival analysis methods . Results : Person-years of exposure ranged by type-specific analysis from 2,645 to 3,188 , with an incidence rate per 100 person-years of 3.6 for HPV-6 , 0.4 for HPV-11 , 5.4 for HPV-16 , and 2.1 for HPV-18 . With censoring at the time of treatment for cervical intraepithelial neoplasia , where done , the mean duration of incident infections was 9.3 , 8.4 , 18.2 , and 16.4 months , respectively , for HPV-6 ( n = 103 ) , HPV-11 ( n = 13 ) , HPV-16 ( n = 142 ) , and HPV-18 ( n = 62 ) . When the duration of HPV infections was truncated at the time of cervical intraepithelial neoplasia detection ( any grade ) , where applicable , mean duration figures were 8.4 , 8.1 , 14.0 , and 15.1 months for HPV-6 , HPV-11 , HPV-16 , and HPV-18 infections , respectively . Conclusions : Previous studies of the mean duration of cervical HPV infection have been based on prevalent infections and /or featured relatively short duration of follow-up . This study tested women for HPV infection over a period of up to 48 months and observed a mean duration of incident HPV-16/HPV-18 infections approximately twice that of HPV-6/HPV-11 . ( Cancer Epidemiol Biomarkers Prev 2007;16(4):709–15 Human papillomavirus ( HPV ) infection causes cervical cancer and genital warts . Young women ( 1106 ) were r and omized to receive one of three formulations of a quadrivalent HPV ( Types 6/11/16/18 ) L1 virus-like particle ( VLP ) vaccine or one of two placebo formulations . The goal was to assess vaccine safety and immunogenicity in baseline HPV 6/11/16 or 18-naïve and previously infected subjects . All three formulations were highly immunogenic . At Month 2 ( postdose 1 ) , among women with vaccine-type antibodies at baseline , vaccine-induced anti-HPV responses were approximately 12- to 26-fold higher than those observed in baseline-naïve women , suggesting an anamnestic response . Following an initial , similar sized decline , anti-HPV responses plateaued and remained stable through end-of- study ( 3.0 years ) . No vaccine-related serious adverse experiences were reported OBJECTIVE : Human papillomavirus ( HPV ) virus-like particle ( VLP ) vaccines have demonstrated effectiveness in preventing persistent HPV infections . Whether protection lasts longer than 18 months and , thus , impacts rates of cervical intraepithelial neoplasia ( CIN ) 2–3 has not yet been established . We present results from an HPV16 L1 VLP vaccine trial through 48 months . METHODS : A total of 2,391 women , aged 16–23 years , participated in a r and omized , double-blind , placebo-controlled trial . Either 40 & mgr;g HPV16 L1 VLP vaccine or placebo was given intramuscularly at day 1 , month 2 , and month 6 . Genital sample s for HPV16 DNA and Pap tests were obtained at day 1 , month 7 , and then 6-monthly through month 48 . Colposcopy and cervical biopsies were performed if clinical ly indicated and at study exit . Serum HPV16 antibody titer was measured by radioimmunoassay . RESULTS : Among 750 placebo recipients in the per protocol population , 12 women developed  HPV16-related CIN2–3 ( 6 CIN2 and 6 CIN3 ) . Among 755 vaccine recipients , there were no cases ( vaccine efficacy 100 % , 95 % confidence interval [ CI ] 65–100 % ) . There were 111 cases of persistent HPV16 infection in placebo recipients and 7 cases in vaccine recipients ( vaccine efficacy 94 % , 95 % CI 88–98 % ) . After immunization , HPV16 serum antibody geometric mean titers peaked at month 7 ( 1,519 milli-Merck units [mMU]/mL ) , declined through month 18 ( 202 mMU/mL ) , and remained relatively stable between month 30 and month 48 ( 128–150 mMU/mL ) . CONCLUSION : The vaccine HPV16 L1 VLP provides high-level protection against persistent HPV16 infection and HPV16-related CIN2–3 for at least 3.5 years after immunization . Administration of L1 VLP vaccines targeting HPV16 is likely to reduce risk for cervical cancer . LEVEL OF EVIDENCE : CONTEXT Every year approximately 2 million US women are diagnosed as having a cervical cytological result of atypical squamous cells of undetermined significance ( ASC-US ) . OBJECTIVE To determine the most efficient and cost-effective management strategy for women in the United States diagnosed as having ASC-US . DESIGN AND SETTING Cost-effectiveness analysis of data from clinical trials , prospect i ve studies , and other published literature . A computer-based model was used to compare 4 management strategies for a cytological result of ASC-US : immediate colposcopy ; human papillomavirus ( HPV ) triage , which includes colposcopy if high-risk HPV types are detected ; repeat cytology , which includes follow-up cytology at 6 and 12 months and referral for colposcopy if a repeat abnormal result occurs ; and reclassifying ASC-US as normal in which a cytological result of ASC-US is ignored . Reflex HPV DNA testing uses either residual liquid-based cytological specimens or sample s co-collected at the time of the initial screening for conventional cytology . Another method , referred to as the 2-visit HPV DNA triage , requires a woman with an ASC-US result to return within 1 month to provide another speciman sample . MAIN OUTCOME MEASURES Years of life saved ( YLS ) , quality -adjusted life-years ( QALYs ) , and incremental cost-effectiveness ratios . RESULTS The least costly strategy for biennial screening was to reclassify ASC-US as normal , result ing in a reduction in total cancer incidence of 75 % for conventional cytology and 84 % for liquid-based cytology compared with no screening . The next least costly strategy was HPV DNA testing result ing in a reduction in total cancer incidence of 86 % for conventional cytology and 90 % for liquid-based cytology , followed by immediate colposcopy with a reduction of 87 % and 91 % , respectively . Compared with reflex HPV DNA testing , a strategy of repeat cervical cytology or delayed HPV testing costs more but is less effective . When all strategies were compared simultaneously , varying frequency and type of cytological test , biennial ( vs every 3 years ) liquid-based cytology with reflex HPV testing had a cost of $ 174 200 per YLS . In a similar comparison , liquid-based cytology with reflex HPV testing conducted every 3 years ( vs every 5 years ) had a cost of $ 59 600 per YLS and was more effective and less costly than a strategy of conventional cytology incorporating repeat cytology or immediate colposcopy conducted biennially . CONCLUSION Reflex HPV DNA testing provides the same or greater life expectancy benefits and is more cost-effective than other management strategies for women diagnosed as having ASC-US In a study involving 13 842 women and 113 gynaecologists , liquid-based cytology and HPV testing for detecting cervical cancer were compared . A total of 1334 women were found to be positive for one or both tests and were invited for colposcopy with biopsy . A total of 1031 satisfactory biopsies on 1031 women were thereafter collected using a systematic biopsy protocol , which was r and om in the colposcopically normal-appearing cervix or directed in the abnormal one . In all , 502 women with negative tests were also biopsied . A total of 82 histologic high- grade squamous intraepithelial lesion ( HSIL ) were reported in biopsies , all from the group with one or both tests positive . Sensitivity and specificity to detect histologic HSIL were 59 and 97 % for cytology , and 97 and 92 % for 
    Output:
    
Results Published data meeting review eligibility criteria were most plentiful for natural history parameters relating to the progression and regression of cervical intraepithelial neoplasia ( CIN ) without HPV typing , and data concerning the natural history of HPV disease due to specific HPV types were often lacking .
Epidemiologic evidence to support age-dependency in the risk of progression and regression of HPV disease was found to be weak , and an alternative hypothesis concerning the time-dependence of transition rates is explored .
No data were found on the duration of immunity following HPV infection .
In the area of clinical management , data were observed to be lacking on the proportion of clinical ly manifest anogenital warts that are treated and the proportion of cervical cancer cases that become symptomatic by stage .