Immunization is one of the important health services for the future with the aim of protecting a person from diseases that can be prevented by immunization (PD3I). The Covid-19 pandemic has disrupted, delayed, and stopped routine immunization services. Various countries experienced a decrease in immunization coverage. This problem will lead to an increase in PD3I cases that were previously controlled or eliminated. The purpose of this literature review was to analyze and synthesize previous studies related to immunization during the Covid-19 pandemic. The result obtained are that immunization services during the pandemic have decreased due to several factors, including the lockdown policy, health workers, vaccine distribution, and the fear of parents to bring their children immunized.