Reviewer ’s report  
 
Title:  CERVICAL cancer risk perception, sexual behaviors and sexually transmitted infections 
amon g Ugandan girls 5 years after Human Papillomavirus vaccine project  
 
Version: 1 Date: 10 Nov 2016 
 
Reviewer:  Robert A  Bednarczyk  
 
Reviewer’s report:  
 
This is an important paper looking at a number of sexual health and women's health outcomes 
following HPV vacc ination in Uganda.  The authors undertook an ambitious analysis, and have 
presented a detailed report on their findings. There are some issues that need to be addressed.  
 
1. Abstract - You describe the population as "sexually active women aged 15 -24 years"  - was 
there any assessment of sexual activity prior to HPV vaccination, or was this assessment 
conducted only at the time of follow -up?  While the school -based vaccination program should 
address potential issues with confounding by indication, as may be s een in other countries with a 
more "opt in" type of vaccination program, it would be interesting to see if any of the sexual 
activity outcomes you assessed were solely after vaccination or if they were present prior to 
vaccination.  
 
2. Background, 1st parag raph - when you describe "5 -year prevalence" of cervical cancer, what 
are you referring to? An average prevalence over a five -year period, or total cases identified over 
a five -year period?  
 
3. Background, 1st paragraph - In the third sentence, add the word  'cancer' after 'commonest'.  
 
4. Background, 2nd paragraph - When describing HPV infection, indicate that it is a necessary, 
but not a sufficient, cause of cervical cancer.  
 
5. Background, 2nd paragraph (and general comment) - Can you please describe the Uga ndan 
HPV vaccination program - which vaccine(s) were used, what was coverage, etc. You mention 
two vaccine types, but there is now a 9 -valent vaccine - will there be any use of that in Uganda?  
 
6. Background, 4th paragraph - You mention no ability to assess  trends in cervical cancer risk 
perceptions, but are there any point estimates that can be presented for context?  
 
7. Background, 5th paragraph - you reference some studies regarding sexual activity outcomes 
after HPV vaccination, but are missing references  to other studies, including those by Jena et al. 
in the US and Smith et al in Canada.  
 
8. Methods, population and sample - Do you have numbers for how many partially vaccinated 
individuals there may be, and what their vaccination status may be (e.g. how ma ny doses at what 
interval?). This is potentially important as recent recommendation changes have moved toward a 
2 dose regimen.  
 
9. Methods, population and sample - As you describe later in your results, the use of different 
cohorts based on vaccine program  initiation is problematic given that it will necessarily result in 
a differential age distribution. You have addressed this well in the results, particularly in the 
multivariable reporting, but it could be clarified a bit here, as well.  
 
10. Methods, quest ionnaire - Was this a validated survey instrument? Did you create the survey 
or use a previously developed instrument?  
 
11. Methods, questionnaire - Since you used a composite score for the risk perceptions outcome, 
it would be useful to mention that the se xual behavior section questions were used as 
independent outcome questions, and not scaled to a score, for clarity.  
 
12. Methods, statistical analysis - you describe sexual debut in terms of age 15 in the 
introduction, but here talk about a categorical vari able split at 18 years, but in your table you 
reference age at sexual debut split at 16 years.  
 
13. Results - Your table headings are not clear in terms of describing which are bivariate and 
which are multivariate regression analyses.  This was problematic as I was reading "Cervical 
cancer risk perceptions" in the manuscript text, which just references table 2 with no context, and 
no reference to what is included as Table 3, which includes multivariable analysis of these 
outcomes.   
 
14. Results, general - I was only able to see the Results tables in the initial version of the 
manuscript, not the R1 version on the online system, and am unsure if there were any updates to 
tables in the R1 version, as the manuscript only references Tables 1 - 4, but there are 5 tables in 
the initial version of the manuscript. Additionally, Table 3 in the text does not match Table 3 (of 
the 5 tables) in the initial version.  Additionally, the supplemental material starts with Table 5, 
but there is already a Table 5 in the initial version (but no tables in the R1 version).  
 
15. Results "High -risk sexual behaviors" - None of the presented tables shows a significant 
difference in age at sexual debut. I am not sure where this statement comes from. Additionally, 
all age at sexual debut data appears to be dichotomized, but you reference a mean in this 
paragraph.  
 
16. Discussion, 2nd paragraph - You mention a difference in vaccine program roll out in terms of 
ethnic tribe, but it would be helpful to know if there are cultural differences be tween ethnic tribes 
with regard to sexual activity that may impact these findings.  
 
17. Discussion, 4th pargraph - again, I do not see the data associated with significantly lower age 
at sexual debut.  
 
18. Supplemental material - there are multiple supplemen tal tables but no reference to them in 
the manuscript text.  
Are the methods appropriate and well described?  
If not, please specify what is required in your comments to the authors.  
 
Yes 
 
Does the work include the necessary controls?  
If not, please specify which controls are required in your comments to the authors.  
 
Yes 
 
Are the conclusions drawn adequately supported by the data shown?  
If not, please explain in your comments to the authors.  
 
Yes 
 
Are you able to assess any statistics in the manuscript or would you recommend an 
additional statistical review?  
If an additional statistical review is recommended, please specify what aspects require further 
assessment in your comments to the editors.  
 
I am able to assess the statisti cs 
 
Quality of written English  
Please indicate the quality of language in the manuscript:  
 
Needs some language corrections before being published  
 
Declaration of competing interests  
Please complete a declaration of competing interests, considering the following questions:  
 
1. Have you in the past five years received reimbursements, fees, funding, or salary from an 
organisation that may in any way gain or lose financially from the publication of this 
manuscript, either now or in the future?  
 
2. Do you hold any  stocks or shares in an organisation that may in any way gain or lose 
financially from the publication of this manuscript, either now or in the future?  
 
3. Do you hold or are you currently applying for any patents relating to the content of the 
manuscript?  
 
4. Have you received reimbursements, fees, funding, or salary from an organization that 
holds or has applied for patents relating to the content of the manuscript?  
 
5. Do you have any other financial competing interests?  
 
6. Do you have any non -financial competing in terests in relation to this paper?  
If you can answer no to all of the above, write 'I declare that I have no competing interests' 
below. If your reply is yes to any, please give details below.  
 
I declare that I have no competing interests.  
 
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