Table 7.

Evidence for women who have been vaccinated against HPV types 16 and 18

Patients/Population	Women who have received HPV vaccination against types 16 and 18
Intervention	Begin screening at age 25 years and/or screening with cytology less frequently than every 3 years
Comparator	Current recommended guidelines for screening with cytology among non-vaccinated females (i.e. cytology starting at age 21 every 1–3 years)
OUTCOME	MAIN RESULT	NUMBER OF STUDIES	QUALITY OF EVIDENCE	COMMENTS
CIN3+
Incidence in vaccinated women	HPV vaccine showed near 100% efficacy in reduction of HPV vaccine type CIN 3+ in women who are HPV naïve	7127–133	Strong	Duration limited at this time at 7–9 years depending on vaccine type, women in RCT had limited number of partners to qualify, efficacy was significantly reduced in those not HPV naïve, no efficacy data are available on vaccinated children; overall efficacy in reduction of all CIN 3+ is much less since non vaccine types continue to contribute to CIN 3+
Population effects	Modeling studies show that vaccination at rates >70–75% is expected to result in 47–95% reduction of CIN 3+. This reduction is likely not to occur until 15–17 years after vaccination programs have reached 70%.	7134–140	Moderate	Modeling studies—indirect evidence, but consistent across studies. Long interval to reduction limits any recommendations to changes in the present moment
Population vaccine coverage	Latest data from the CDC show that 32% of targeted female youth have received 3 dose HPV vaccine	1126	Strong	No data are available whether the targeted youth including ‘catch-up’ have already initiated sexual activity and are less likely to benefit
Colposcopies	Studies have shown that PPV of cytology would be negatively impacted by the HPV vaccine. Modeling studies suggest fewer unnecessary diagnoses/treatments if screening recommendations revised to delay onset of screening or increase intervals.	11 141–151	Moderate	Modeling studies are indirect evidence. If women reduced screening, the effect of HPV vaccination would be negated. Some of the models suggest that altering strategies would not be cost-effective and potentially harmful. Results from RCTs not generalizable due to intensity of follow-up.