Table 1.
The effect of missing OPV at birth on mortality up to age 12 months.
| A. The effect of missing OPV at birth on mortality up to age 12 months. Before and after the 18 October 2004 OPV campaign | ||||
|---|---|---|---|---|
| OPV0 MR (deaths/pyrs) |
No OPV0 MR (deaths/pyrs) |
Crude HR OPV0 versus No OPV0 (95% CI) |
Adjustedd HR OPV0 versus No OPV0 (95% CI) |
|
| Overall resulta(N = 4345) | ||||
| All | 49.2 (149/3031) | 34.9 (30/859) | 1.41 (0.95–2.09) | 1.45 (0.97–2.17) |
| Male | 54.1 (82/1514) | 20.0 (9/451) | 2.72 (1.37–5.41) | 2.82 (1.41–5.65) |
| Female | 44.2 (67/1517) | 51.5 (21/408) | 0.86 (0.53–1.40) | 0.87 (0.53–1.44) |
| P interaction | 0.008 | 0.006 | ||
| “Before” OPV campaign – with censoring on 17 October 2004 (N = 4048)b | ||||
| All | 54.3 (129/2376) | 57.0 (22/386) | 0.98 (0.61–1.56) | 0.98 (0.60–1.60) |
| Male | 59.9 (72/1203) | 39.4 (8/203) | 1.56 (0.75–3.27) | 1.58 (0.74–3.35) |
| Female | 48.6 (57/1174) | 76.5 (14/183) | 0.65 (0.36–1.18) | 0.64 (0.35–1.19) |
| P interaction | 0.07 | 0.06 | ||
| “After” OPV campaign – follow-up time starts on or after 18 October 2004 (N = 2202)c | ||||
| All | 30.5 (20/655) | 16.9 (8/473) | 2.00 (0.87–4.61) | 1.87 (0.75–4.64) |
| Male | 32.1 (10/312) | 4.0 (1/248) | 8.88 (1.13–69.7) | 8.26 (1.02–66.8) |
| Female | 29.1 (10/343) | 31.1 (7/225) | 1.03 (0.39–2.75) | 0.95 (0.33–2.72) |
| P interaction | 0.06 | 0.06 | ||
| B. Changes in mortality rates before and after 18 October in the year of the national OPV campaign and the previous year | ||||
| Overall MR (deaths/pyrs) | MR before 18 October (deaths/pyrs) | MR after 18 October (deaths/pyrs) | HR after/before 18 October (95% CI) | |
| “2003-birth-cohort” Born 1/1-2003-17/10-2003 | ||||
| Overall | 53.6 (74/1381) | 58.8 (34/578) | 49.8 (40/804) | 0.85 (0.53–1.34) |
| Male | 67.4 (45/668) | 67.3 (19/282) | 67.5 (26/385) | 1.00 (0.55–1.82) |
| Female | 40.6 (29/714) | 50.7 (15/296) | 33.5 (14/418) | 0.66 (0.32–1.37) |
| “2004-birth-cohort” Born 1/1–2004-17/10-2004 | ||||
| Overall | 40.2 (59/1468) | 66.0 (40/606) | 22.1 (19/862) | 0.33 (0.19–0.58) |
| Male | 32.2 (24/746) | 56.2 (18/320) | 14.1 (6/426) | 0.25 (0.10–0.63) |
| Female | 48.5 (35/721) | 77.0 (22/286) | 29.8 (13/436) | 0.39 (0.20–0.77) |
Note: MR = mortality rate per 1000 person years (pyrs). HR = hazard ratio obtained in Cox proportional hazards models with age as underlying timescale.
a
As presented in the original paper, but reversed to illustrate the OPV0 versus NoOPV0 comparison.
b
These children were enrolled before 18 October 2004 and contributed risk time to October 18, 2004.
c
These children could be enrolled before 18 October 2004, but only contributed risk time from 18 October 2004.
d
Adjusted for season of OPV0, suburb, maternal education, place of enrolment, and lowest quartile arm circumference at enrolment as done in the original analysis [2].