Table 1.

Inclusion and exclusion criteria.

	Inclusion criteria	Exclusion criteria
Population	Human population 50 years of age and older	Less than 50 years of age; populations out of scope (e.g., pregnant women and healthcare professionals)
Intervention	Routine vaccination programs	Vaccines out of scope (e.g., travel vaccines)
Comparator	Not applicable	Not applicable
Outcomes	Barriers and drivers (e.g., access, behaviors and beliefs, availability of information, affordability, advocacy, policy)	Outcomes out of scope (e.g., studies investigating vaccine immunogenicity, efficacy, effectiveness); not about vaccines/vaccination or secondary outcomes
Study design	Any (except editorial or commentary paper)	Secondary research; editorial or commentary
Other	Written in English; published January 1, 2016 to December 22, 2021