Means ± SEM are reported in the text. Using the same methods previously reported for analysis of the NSHAP vaginal swab data22 (link), analyses utilized the sample weights distributed with the dataset to adjust for differential probabilities of selection and differential non-response.17 Standard errors were estimated using the linearization method, taking into account sample stratification and clustering.34 All analyses were conducted using Stata Statistical Software Release 13.1 (StataCorp, College Station, TX).