Global COVID-19 vaccination in infants and children: Effectiveness, safety, and challenges

COVID-19 Vaccines, which include mRNA and inactivated vaccines, have been proven effective and safe for infants and children aged more than six months in reducing the severity of the disease, hospitalization, multisystem inflammatory syndrome in children, and death. Nonetheless, the real-world effectiveness of these vaccines in preventing infection is generally lower than in clinical trials due to the emergence of variants of concern, especially the Omicron strains. Despite the availability of vaccines for children, their uptake remains low globally, particularly among parents who are hesitant to vaccinate their children. This review article aims to provide a comprehensive overview of COVID-19 vaccine safety and efficacy from clinical trials and the current COVID-19 vaccine recommendations for infants and children aged 6 months to < 12 years for 2023-2024, discuss the progress made in vaccine implementation and real-world effectiveness, and address the knowledge gap and future directions.