What was wrong?
Why serotype replacement, of course! So they are expanding from 7 serotypes to 13 serotypes.
Copy of your post ---
"# MinorityView on Fri, 20th Mar 2009 6:15 pm
“Wyeth (WYE.N) on Monday said trials of an improved form of its blockbuster Prevnar vaccine suggest it is as safe as the original and may offer broader protection against infections in infants and young children.”
As safe as the original…which was tested against the unknown safety profile of an experimental vaccine…everyone feel really, really safe?"
Exactly what I was thinking! Also - what was wrong with the "original" that required them to create a new one???