 This study aimed to investigate changes in guardians' willingness to administer COVID-19 vaccine to their children, allow co-administration of other vaccines, and administer a booster dose. The survey was conducted six months after a previous study using the Xiaodomiao app, with 9,424 participants from September 15 to October 8, 2021. Results showed that 86.68% of guardians were willing to vaccinate their children with COVID-19 vaccine, which was an increase of approximately 16% compared to the previous study. Guardians aged greater than or equal to 40 years, healthcare workers, and those with children aged greater than or equal to three years were more willing to vaccinate their children. Approximately 77% of guardians were willing toward co-administration of COVID-19 and influenza vaccines, while approximately 64% were willing toward co-administration of other non-immunization program vaccines with the COVID-19 vaccine for their children. The primary reasons for reluctance toward vaccine co-administration were concerns about safety and effectiveness. If necessary, 92% of guardians were willing to receive a COVID-19 booster, and 82% were willing to vaccinate their children with a COVID-19 booster. The study aims to facilitate the formulation of successful strategies for implementing COVID-19 vaccinations, co-vaccinations, and COVID-19 booster doses for children aged less than six years. This article was authored by Living Ma, Jin Yang, Ting Zhong, and others. We are article.tv, links in the description below.