Vaccine coverage rate: opportunities and challenges in managing the expanded program on immunization

Background: This study aims to determine the vaccine coverage rate in the expanded immunization program of children born from 2016-2020 through periods with and without the impact of the COVID-19 pandemic. Methods: The retrospective cross-sectional study with data, taken from the National Immunization Information System at two points of time (January 2021 and September 2022), was conducted on all children born from 2016 to 2020 with registered addresses in Ho Chi Minh City. Results: There are 3,1% of the population from other provinces entering Ho Chi Minh City and 1,8% of Ho Chi Minh City's population leaving the city. The overall fully vaccinated rate of children from 2016 to 2020 is 86,9%. The second measles coverage rate and diphtheria pertussis tetanus 4th dose (DPT4) coverage rate for children born in 2016-2020 was 78,1% and 72,4%. The DPT4 missed dose rate increased from 14,2% to 24,6% and the second measles missed shot rate increased from 8,9% to 19,5%. Under the impact of the COVID-19 pandemic, the vaccination coverage rate by age group decreased during the COVID-19 epidemic stages. After the epidemic, it recovered but the rate was not high. Conclude: There was a fluctuation in HCM population when retrospectively examining data at 2 points of time. The rate of vaccination coverage of children under and over 1 year old does not meet the target. The missed dose percentage of vaccines for children under 1 year old is low (diphtheria pertussis tetanus 1st dose (DPT1)-measles 1 or DPT1-3), while the proportion of missed is high in DPT3-DPT4 and Measles 1-Measles 2. The retrospective cross-sectional study only used retrospective data up to September 2022, so it is hard to illustrate a clear recovery after the COVID-19 pandemic. More time is needed for the observation.