Abstract
In 2008, a national human
papillomavirus (HPV) immunization program using a bivalent vaccine against HPV
types 16 and 18 was implemented in Scotland along with a national surveillance
program designed to determine the longitudinal effects of vaccination on HPV
infection at the population level. Each year during 2009–2013, the surveillance
program conducted HPV testing on a proportion of liquid-based cytology samples
from women undergoing their first cervical screening test for precancerous
cervical disease. By linking vaccination, cervical screening, and HPV testing
data, over the study period we found a decline in HPV types 16 and 18,
significant decreases in HPV types 31, 33, and 45 (suggesting
cross-protection), and a nonsignificant increase in HPV 51. In addition, among
nonvaccinated women, HPV types 16 and 18 infections were significantly lower in
2013 than in 2009. Our results preliminarily indicate herd immunity and
sustained effectiveness of the bivalent vaccine on virologic outcomes at the
population level.
Below: Figure. Analyses
for 5,715 liquid-based cytology cervical samples from vaccinated and
nonvaccinated women, for which valid human papillomavirus (HPV) testing results
were available, Scotland, 2009–2013. A) Proportion and 95% CIs for samples with
positive results for each HPV type. B) Difference in the proportion positive
and associated 95% CIs for the difference between vaccinated and nonvaccinated
women, by HPV type. Other than HPV types 16 and 18, the 95% CIs of the
difference were corrected for multiple testing using by using the Bonferroni
correction. *Significant change.
Full article at: http://goo.gl/AW79p3
By:
Author affiliations: Health Protection Scotland,
Glasgow, Scotland, UK (R.L. Cameron, J. Love, S. Ahmed, K.G.J. Pollock); University
of Strathclyde, Glasgow (K. Kavanagh, J. Pan, C. Robertson); Scottish
Human Papillomavirus Reference Laboratory, Edinburgh, Scotland, UK (K.
Cuschieri); University of Edinburgh, Edinburgh (T. Palmer)
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