Do patients who were vaccinated with one or two doses of PPSV23 before age 65 need an additional dose of PPSV23 at age 65 or later?

Yes, but only if they have already received PCV13. If they have not received any PCV product, or their history of PCV vaccination is unknown, they may receive a single dose of either PCV15 or PCV20. If they have already received either PCV20 or PCV15, then no additional PPSV23 doses are needed.