M.M.
So I have done some research into this and here's what I know....
PCV13 (aka Prevnar) is just a version of PCV7 with some newer strains that have become more common in the recent years. The original PC vaccine contained just the most common forms of the virus, which are very uncommon due to the use of the vaccine, so they developed a new one for the newer (now more common) strains. (The problem with this is once we have this vaccine around for awhile the strains it vaccinates against will become more uncommon and newer strains will develop...Possibly more dangerous/antibiotic resistant strains)
The only reason you would vaccinate your DS with PC13 is so he will have SOME immunity to the newer strains. But in my opinion, PC is really normally not serious in anyone over 2, so I don't think your 3 yr old is at risk that much. I wouldn't do it. But that's your decision as his mom. I LOVE Dr. Bob Sears for vaccine info. His site is www.thevaccinebook.com. I got this info from his Facebook...
"The latest CDC study estimates that in 2007 there were about 4600 cases of severe PC disease (meningitis, hospitalized pneumonia, bone and bloodstream infections) in children less than 5 years of age. About 64% of these infections were caused by strains covered by the new Prevnar 13. Only about 2% of these infections were caused by the 7 strains in the old Prevnar 7. That means that about 34% of serious PC infections are caused by strains NOT in either vaccine. Future vaccines will likely incorporate more and more strains."
Here's a link to where Dr. Bob Sears talks about the new PCV13 vaccine on his FB.....
http://www.facebook.com/topic.php?uid=116317855073374&...
EDIT: Just wanted to add, that your state, MN, does not require kids to be fully vaccinated to attend school. You have the option to state that you do not wish your child to be vaccinated due to philosophical reasons. (You can also use religious or medical reasons as well.) Don't let anyone make you think you legally HAVE to vaccinate your kids!!! YOUR CHILD, YOUR CHOICE! Here's a link on how to use vaccine exemption in your state...
http://www.nvic.org/Vaccine-Laws/state-vaccine-requiremen...
Oh, and I wanted to add that according to the CIA world fact book, the United states has one of the highest infant mortality rates of any developed nation. Higher than Cuba and North Korea. We also have the highest vaccination rates....hmmm...just a thought.