COVID-19 IMPACT ON HUMAN PAPILLOMAVIRUS IMMUNIZATION PROGRAM IN PERU: MODELLING TIME AND CATCH-UP RATES TO CLOSE THE IMMUNIZATION GAP

Abstract

Intro: Between 2020 and 2021, the school-based human papillomavirus (HPV) vaccination program was temporarily interrupted in Peru due to the COVID-19 pandemic. While immunization services resumed in March 2022, the efforts and time required for immunization services to catch-up girls who missed doses of HPV vaccine are unclear. We aimed to estimate the impact of the pandemic on the number of HPV doses administered and time needed to reverse to pre- pandemic coverage levels. Methods: A previously published model (Saxena et al 2021) was adapted to the Peruvian context to quantify the deficit in HPV doses administered to Peruvian girls aged 9-13 years between 2020 and 2021. The model included the following periods: pre-pandemic, COVID-19 pandemic, transition period (linear increase until reach an assumed rate) and catch-up (rates higher than 2019). The monthly HPV vaccine doses were compared with 2019 levels. The model estimated the cumulative deficit in doses administered and the projected time and catch-up rates/number of doses required to close the 2020/2021 HPV immunization gap relative to 2019. Findings: Based on administrative data, we estimated that a total of 430,000, 358,207, and 301,650 doses of HPV vaccine were administered to 9-13 years girls in Peru in 2019, 2020, and 2021, respectively. Annual doses decreased by 16.7% and 29.8% in 2020 and 2021 compared to 2019. Starting on October 2022 with a monthly catch-up rate of 5% (1,792 additional doses/month) and 10% (3,588 additional doses/month), the projected dose deficit was expected to be cleared in August 2025 and March 2024, respectively. Conclusion: A marked disruption to HPV routine immunization occurred in 2020 and 2021 in Peru, with HPV vaccine coverage estimated to have fallen between 16.7-29.8%. The recovery to pre-pandemic coverage and catch-up of missed doses require a sustained increase in vaccination over multiple years to prevent HPV infection/disease in near and long term.