Sensitivity analysis pcv model

Question

To assess the sensitivity of the IPD predictions produced by the epidemiological model (assuming complete replacement) effects of 24 alternative scenarios regarding the role of certain serotypes in PCV10 and PCV13 were calculated, separately for <5 and 5+ year olds.

Answer

The results, shown in the table below, can be summarized as follows:

For <5 year olds:

• Inclusion of direct effects for 19A in PCV10 decreses the advantage of PCV13 from the default level of approximately 30 cases by 15.
• Exclusion of 3 from PCV13 decreses the PCV13 advantage by approximately 2 cases. Inclusion of 6A in PCV10 decreses the PCV13 advantage by 4 cases.

For 5+ year olds:

• Exclusion of serotype 3 from PCV13 will decrease its advantage by 130 cases, practically eliminating the advantage.
• Inclusion of 6A in pcv10 will inrease the PCV13-advantage by 30 (as 6A is not a good vaccine type for adults) and assuming that 6C carriage proportion (of 6AC) is 50% (instead of the default level of 33%) will increase it by 10.

Columns of the table:
_
3inP13    =  inclusion of serotype 3 in PCV13
6Cprop    =  assumed proportion of 6C carriers among the 6A/C carriers
6AinP10   =  inclusion of serotype 6A in PCV10
19AinP10  =  inclusion of serotype 19A in PCV10
_
<5_P10  Decrease in IPD among <5 yo:s after PCV10 (IPD=99 when no vaccination)
<5_P13  Decrease in IPD among <5 yo:s after PCV13 
<5_Diff Additional decrease in IPD due to PCV13 (vs PCV10)
_
5+_P10  Decrease in IPD among 5+ yo:s after PCV10 (IPD=687 when no vaccination)
5+_P13  Decrease in IPD among 5+ yo:s after PCV13
5+_Diff Additional decrease in IPD due to PCV13 (vs PCV10)

Levels of protection considered:
0    =  no protection
dir  =  direct efficacy against disease (*), no indirect effects
         (*) 80% coverage, 10% waning per year, 80% efficacy against 
             disease for newly vaccinated 
full =  100% overall effectiveness

 3inP13  6Cprop  6AinP10 19AinP10   <5_P10 <5_P13 <5_Diff  5+_P10 5+_P13  5+_Diff
 ------  ------  ------- --------                 --------               ----------
 0       33%     0       0          41     71     30        133    115    -18
 0       33%     0       dir        55     70     15        133    114    -19
 0       33%     full    0          42     71     29         92    114     22
 0       33%     full    dir        59     71     12         92    114     22
 0       50%     0       0          41     72     31        133    137      4
 0       50%     0       dir        55     72     17        133    137      4
 0       50%     full    0          45     72     27        114    137     23
 0       50%     full    dir        61     72     11        115    137     22
 _
 dir     33%     0       0          41     73     32        133    115    -18
 dir     33%     0       dir        55     73     18        133    115    -18
 dir     33%     full    0          42     73     31         92    115     23
 dir     50%     0       0          41     74     33        133    138      5
 dir     50%     0       dir        55     74     19        133    137      4
 dir     50%     full    0          45     75     30        114    137     23
 dir     50%     full    dir        61     74     13        115    138     23
 dir     33%     full    dir        59     73     14         92    114     22
 _
 full    33%     0       0          41     74     33        133    249    116
 full    33%     0       dir        55     74     19        133    249    116
 full    33%     full    0          42     74     32         92    249    157
 full    33%     full    dir        59     74     15         92    249    157
 full    50%     0       0          41     75     34        133    267    134
 full    50%     0       dir        55     75     20        133    267    134
 full    50%     full    0          45     75     30        114    267    153
 full    50%     full    dir        61     75     14        115    267    152