The World Health Organization (WHO) has launched a global campaign named ‘The Big Catch-Up’ to boost vaccination rates among children worldwide. The pandemic has led to a decline in vaccine coverage, leaving over 25 million children worldwide without at least one vaccination in 2021. This has created a high risk of vaccine-preventable outbreaks such as measles, polio, and yellow fever. WHO, along with UNICEF, Gavi, the Vaccine Alliance, the Bill & Melinda Gates Foundation, and other health partners, is focusing on the 20 countries where 75% of these children live. The campaign aims to restore immunization rates and strengthen health care workforces, improve health service delivery, build trust and demand for vaccines, and address gaps and challenges to restoring vaccination rates. Routine vaccines are typically a child’s first entry into their health system, and children who miss out on their early vaccines are at added risk of being cut out of healthcare in the long run. Therefore, it is essential to reach and vaccinate these children as soon as possible to save lives. Countries, global partners, and local communities must come together to strengthen services and build trust to accomplish this goal.