Population Wide Administration Of The Antibiotic (PWA) - Epidemiology Assignment

Internal Code: MAS5916

Epidemiology Assignment:

The study methodology can be briefly summarised as follows: Population?wide administration of the antibiotic (PWA) was undertaken, with all people offered the drug regardless of age or gender. Ten months later, women presenting to a health clinic (that was primarily for ante?natal care) were invited to participate (and 99% agreed). Women performed their own vaginal swabs, which were then tested for evidence of infection. A similar approach had been used before the PWA. The overall prevalence of infection was determined. In addition, the prevalence of infection before and after the PWA was then compared. The prevalence of infection after the PWA was also compared between those who said they had received the antibiotic and those who said they had not. Based on Marks M, Bottomley C, Tome H et al. Mass drug administration of azithromycin for trachoma reduces the prevalence of genital Chlamydia trachomatis infection in the Solomon Islands. Sex Transm Infect Questions: 1) What do you think the main sources of bias might be in a study such as this? For TWO of these, explain the likely effect on the main study outcomes (overall prevalence and the two comparisons mentioned above that were the focus of the study), or indicate why you don’t feel you can predict the likely effect. 2) Just based on this information (i.e. don’t take into account the potential sources of bias in the study), do you agree with the interpretation by the authors that there was an effect on C. trachomatis infection prevalence but not on N. gonorrhoea infection prevalence? Why or why not?