@Roberta,
I think a lot of people don't know that about the pneumonia shot, Roberta, nor do the people in places like the pharmacies bother to inform them that it's not an annual vaccination, like the flu shot. When people, particularly older folk, come in for a flu shot, they routinely ask, "Do you also want the pneumonia vaccine?" They really should not do that, both because it's a subtle form of encouragement to get that vaccine, and also because the person may have had a prior pneumonia shot, or had one within the past five years, and they just don't require or need another dose.
When I got my pneumonia shot from my physician, he told me the correct info on whether, if ever, I might require an additional dose at a later time, so that was how I learned about it.
I'm glad I could pass along the info to you. I wish they would post the same info in the pharmacies, or have it available for people to read.