***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 .We compared vaccine coverage achieved by 2 different delivery strategies for the quadrivalent human papillomavirus ( HPV ) vaccine in Tanzanian schoolgirls . Methods .In a cluster-r and omized trial of HPV vaccination conducted in Tanzania , 134 primary schools were r and omly assigned to  class-based ( girls enrolled in primary school grade [ class ] 6 ) or age-based ( girls born in 1998 ; 67 schools per arm )  vaccine delivery . The primary outcome was coverage by dose . Results .There were 3352 and 2180 eligible girls in schools r and omized to class-based and age-based delivery , respectively .  HPV vaccine coverage was 84.7 % for dose 1 , 81.4 % for dose 2 , and 76.1 % for dose 3 . For each dose , coverage was higher in class-based schools than in age-based schools ( dose 1 : 86.4 % vs 82.0 % [ P = .30 ] ; dose 2 : 83.8 % vs 77.8 % [ P = .05 ] ; and dose 3 : 78.7 % vs 72.1 % [ P = .04 ] ) . Vaccine-related adverse events were rare . Reasons for not vaccinating included absenteeism ( 6.3 % ) and parent refusal ( 6.7 % ) . School absenteeism rates prior to vaccination ranged from 8.1 % to 23.5 % . Conclusions .HPV vaccine can be delivered with high coverage in schools in sub-Saharan Africa . Compared with age-based vaccination , class-based vaccination located more eligible pupils and achieved higher coverage .  HPV vaccination did not increase absenteeism rates in selected schools . Innovative strategies will be needed to reach out-of-school girls . Clinical Trials Registration . NCT01173900 Background There are few data on factors influencing human papillomavirus ( HPV ) vaccination uptake in sub-Saharan Africa . We examined the characteristics of receivers and non-receivers of HPV vaccination in Tanzania and identified reasons for not receiving the vaccine . Methods We conducted a case control study of HPV vaccine receivers and non-receivers within a phase IV cluster-r and omised trial of HPV vaccination in 134 primary schools in Tanzania . Girls who failed to receive vaccine ( pupil cases ) and their parents/guardians ( adult cases ) and girls who received dose 1 ( pupil controls ) of the quadrivalent vaccine ( Gardasil ™ ) and their parents/guardians ( adult controls ) were enrolled from 39 schools in a 1∶1 ratio and interviewed about cervical cancer , HPV vaccine knowledge and reasons why they might have received or not received the vaccine . Conditional logistic regression was used to determine factors independently associated with not receiving HPV vaccine . Results We interviewed 159 pupil/adult cases and 245 pupil/adult controls . Adult-factors independently associated with a daughter being a case were older age , owning fewer household items , not attending a school meeting about HPV vaccine , and not knowing anyone with cancer . Pupil-factors for being a case included having a non-positive opinion about the school de-worming programme , poor knowledge about the location of the cervix , and not knowing that a vaccine could prevent cervical cancer . Reasons for actively refusing vaccination included concerns about side effects and infertility . Most adult and pupil cases reported that they would accept the HPV vaccine if it were offered again ( 97 % and 93 % respectively ) . Conclusions Sensitisation messages , especially targeted at older and poorer parents , knowledge retention and parent meetings are critical for vaccine acceptance in Tanzania .  Vaccine side effects and fertility concerns should be addressed prior to a national vaccination program . Parents and pupils who initially decline vaccination should be given an opportunity to reconsider their decision 
    Output:
    
Perceived barriers including accessibility and cost concerns were important for acceptance , as were cues to action from healthcare providers and governments .
This review suggests that acceptability of the HPV vaccine in countries in this region will be high .
Broad knowledge gaps were highlighted regarding HPV and cervical cancer and these should be addressed .