That's because other strains weren't covered by the original vaccines: Strains 16 and 18 were the high risk strains covered in the 2008 roll-out, the roll-out to young girls of the broader vaccine covering other high risk strains didn't start until 2017.
“In 2017, one of the first birth cohorts of women in Denmark who were HPV-vaccinated as teenage girls in 2008 reached the screening age of 23 years,” Nonboe explained."
It will take several more years to see the effects on other strains. It seems to have been wildly successful so far.
“In 2017, one of the first birth cohorts of women in Denmark who were HPV-vaccinated as teenage girls in 2008 reached the screening age of 23 years,” Nonboe explained."
It will take several more years to see the effects on other strains. It seems to have been wildly successful so far.