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Table 4 Details of scenarios and estimates of the incremental number of paralytic cases prevented, reduction of time until WPV elimination by serotype, and vaccine doses needed compared to the reference for northwestern Nigeria (see Additional file 1 and Duintjer Tebbens et al. (2013)[20] for other model assumptions fixed across all scenarios)

From: The potential impact of expanding target age groups for polio immunization campaigns

Expanded age group scenario

Target age groups of SIAs (in years), by rounda

Paralytic cases prevented (2012–2015) [%]

Reduction in WPV1 elimination time (days)

Additional vaccine doses administered (through 2014) (millions)

Reference case: No expanded age groups

0-4 (all rounds)

Reference

Reference

Reference

Hypothetical retrospective scenarios:

    

Relative coverage in under-vaccinated during Feb (bOPV) and Mar (tOPV) 2012 SIAs increased by 0.2

0-4 (all rounds)

93 [53%]

56

0.2

Expand Feb (bOPV) and Mar (tOPV) 2012 SIAs to all ages

All ages (Feb and Mar 2012); 0–4 (all other rounds)

76 [44%]

49

46.3

  

11/10/2012 (bOPV)

  

Expand Feb (bOPV) and Mar (tOPV) 2012 SIAs to all ages with relative coverage in under-vaccinated subpopulation increased by 0.2

All ages (Feb and Mar 2012); 0–4 (all other rounds)

130 [75%]

302

46.5

Prospective scenarios:

    

Expand Nov 2013 bOPV SIAs through 14 year olds

0-14 (Nov 2013); 0–4 (all other rounds)

1 [0.6%]

17

9.3

Expand Nov 2013 bOPV SIAs to all ages

All ages (Nov 2013); 0–4 (all other rounds)

2 [1.0%]

32

29.6

Relative SIA coverage in under-vaccinated subpopulation increased by 0.05 from Nov 2013 on

0-4 (all rounds)

2 [1.2%]

58

0.4

  1. Notes:
  2. aSIAS in 2012 on 2/18 (bOPV), 3/31 (tOPV), 5/12 (bOPV), 7/7 (bOPV), 9/15 (bOPV), 10/4 (bOPV), 11/10 (bOPV), 12/1 (tOPV), and 12/15 (bOPV). SIAs in 2013 on 1/12 (bOPV and tOPV), 2/2 (bOPV), 3/2 (tOPV), 4/20 (bOPV), 5/11 (bOPV), 6/15 (bOPV), 7/6 (bOPV), 9/7 (tOPV), 10/12 (bOPV), 11/9 (bOPV), 12/14 (bOPV). For 2014 and 2015, we assume SIAs occur on the 15th of all months except August.