Prevnar vs. Pneumovax

[bbpiano1]

---

Members do not see this ad.

So we were discussing how Prevnar is conjugated and Pneumovax is just polysaccharide. I'm wondering why they just don't conjugate the 21 polysacchs in Pneumovax to create a better anamnestic response.

It doesn't seem like making a conjugate is all that involved and I don't think 21 antigens is excessive, so what's the problem???

 

[bks524]

I don't know the answer to your question, but prevnar works pretty well. I would also think that if there were an advantage to having a better S.pneumo vaccine then it would be out by now. I mean look at the whole HPV thing. Gardasil is the one that took hold even though the other one (GSK I think) protects against 16 and 18 also. Better product generally wins out-though maybe cost is a big factor in your question.

 

[generic]

I thought I had heard that the conjugate vaccine worked much better in infants/children, whereas the polysaccharide produced an adequate immune response in the older folks to whom it's usually given--therefore from a cost standpoint it makes more sense to do PS vaccine for 21 valent.

Tangentially thinking: will the changing profile of s. pneumoniae subtypes render prevnar obselete in the future? I wonder if they'll have to change to a >7 valent infant vaccine to cover other types that have been encouraged by the success of prevnar?

 

[Delgato]

short answer is cost and effort. effort and cost involved in conjugation is expensive. significantly increasing the cost decreases your potential market. an updated prevnar containing 13 serotypes is under review at FDA. so there will be a new one with more serotypes.