Because pneumococcal recommendations have changed over the years, providers should not assume which pneumococcal vaccines a patient has received. Ideally, providers and patients should try to verify which vaccines were received, including by checking medical records and the jurisdiction’s immunization information system (immunization registry) where the patient was likely vaccinated.
Per the CDC “General Best Practices Guidelines for Immunization”, self-reported doses of influenza and PPSV23 are acceptable. All other vaccines must be documented with a written, dated record. This means that if a patient reasonably recalls receiving a pneumococcal polysaccharide vaccination after turning 65, you may accept that as a history of PPSV23 and administer either PCV15 or PCV20.
Alternatively, if vaccination records cannot be obtained, and the patient is uncertain whether they received PCV13 or PPSV23, you may choose to classify the patient as having an unknown vaccination history and administer either PCV20 alone or PCV15 followed by PPSV23 one year later.