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. Author manuscript; available in PMC: 2013 May 1.
Published in final edited form as: Hum Immunol. 2012 Mar 3;73(5):474–479. doi: 10.1016/j.humimm.2012.02.016

Table 2.

Demographic Description and Comparison of the Two Cohorts (N=764)

Cohort 1 Cohort 2 Combined P
Value*
Total N Count (percentage) 388 (49.9) 376 (50.1) 764 (100) NA
Median age at enrollment, years (IQR) 15.0 (13.0 to 17.0) 15.0 (13.0 to 17.0) 15.0 (13.0 to 17.0) <0.001
Median age at first measles vaccination, months (IQR) 15.0 (15.0 to 16.0) 15.0 (15.0 to 16.0) 15.0 (15.0 to 16.0) 0.96
Median age at second measles vaccination, years (IQR) 8.0 (5.0 to 11.0) 5.0 (4.0 to 10.0) 5.0 (4.0 to 11.0) <0.001
Median time from 2nd measles vaccination to enrollment, years (IQR) 6.7 (4.9 to 8.2) 8.5 (6.4 to 10.4) 7.4 (5.6 to 9.2) <0.001
Females Count (percentage) 176 (45.4) 161 (42.3) 337 (44.1) 0.48
Race Count (percentage)
Caucasian
African-American
All Other Races		 345 (88.9)
4 (1.0)
39 (10.1)		 271 (72.1)
85 (22.6)
20 (5.3)		 616 (80.6)
91 (11.9)
59 (7.7)		 <0.001
Hispanic Count (percentage) 6 (1.6) 9 (2.4) 15 (2.0) 0.02
*

P-values are calculated using chi-square tests for categorical variables and Mann-Whitney tests for continuous variables.