Cost effectiveness sensitivity

Question

The effects of alternative vaccine compositions on the outcomes of the cost-effectiveness analysis were assessed. Five modifications for PCV10 and one for PCV13 were considered.

Answer

Conclusion: The assumption about serotype 3 in PCV13 is crucial. In addition, assumptions about the role of 6A in PCV10 is important.

If serotype 3 is not included as a vaccine type in PCV13, then the differences between PCV10 and PCV13 in IPD (shown below), quality adjusted life years gained (not shown) and medical costs (not shown) are relatively minor. Therefore, if the vaccine price is equal for PCV10 and PCV13, then in view of the intrinsic uncertainties in the model, PCV10 and PCV13 can be regarded as roughly equally cost-effective.

Rationale

 Three separate tables are displayed, each corresponding to a different quantity. 
 The three quantities of interest are:
 *PCV13adv.inIPD 
   = (IPD under PCv10) - (IPD under PCV13)
     if positive, PCV13 saves IPD cases compared to PCV10
 *price of PCV13 
   =  if PCV10 price set at 20e, what is the matching price for PCV13?
 *ICER 
   = incremental cost-effectiveness ratio for PCV10 at price 20e
     (in this table, this value is also average cost per QALY)

 rows (vaccine composition PCV10 and its 5 modifications):
  [1]  pcv10       
  [2]  pcv10 + 19A(direct effects only)
  [3]  pcv10 + 6A      
  [4]  pcv10 + 19A(direct only) + 6A
  [5]  pcv10 + 19A(full)  
  [6]  pcv10 + 19A(full) + 6A = PCV13 - 3
 columns (vaccine composition PCV13 with or without serotype 3):
  [1]  pcv13 - 3 (excluding serotype 3)     
  [2]  pcv13

                 PCV13adv.inIPD   price of PCV13    ICER
                 ==============   ==============    ===============
                 PCV13-3  PCV13   PCV13-3  PCV13    PCV13-3   PCV13
                   ---     ---    -------  -----     -----     ----
  pcv10             12     150       18     38        8077     8077
  pcv10+19Ad        -2     134       17     37        7714     7714
  pcv10+6A          50     188       25     55       13590    13590
  pcv10+19Ad+6A     32     169       24     52       12724    12724
  pcv10+19Af       -31     105       15     32        6198     6199
  pcv10+19Af+6A      *     137        *     43           *     9672
                                 ----------------
                                 (PCV10 price=20)