Figure 1.

Prevalence and severity of symptoms by antibody status: positive (+) or negative (−)

Age- and gender-adjusted logistic regression models indicate higher prevalence in 239 antibody-positive versus 3,437 antibody-negative individuals for all symptoms (p < 0.001; Table 2), except where indicated as not significant (NS). Samples that tested reactive for antibodies, including samples with weak reactivity (OD:CO ratio ³ 0.5), were re-tested and considered positive if the re-test was reactive (OD:CO ratio > 1.0).