Volume 21, Number 12—December 2015
Kinetics of Serologic Responses to MERS Coronavirus Infection in Humans, South Korea
|Clinical factors||Difference in rates of change in log antibody titers
|PRNT50 titer||p value||S1-ELISA OD ratio||p value|
|Age >60 y†||0.05||0.22||−0.03||0.65|
|Incubation period, d†||0.01||0.16||0.02||0.004|
|Use of corticosteroid†||0.06||0.37||−0.04||0.58|
|Use of antiviral drugs†||0.06||0.10||0.05||0.35|
*Differences in rates of change and p values were estimated by using linear mixed models; positive value indicates a faster increase in antibody titer. Given that the antibody titers exhibited an S-shaped pattern, the analysis was restricted to data for log-phase antibody responses by manually removing data from the inductive/steady-state phase. Increases in antibody titers during the log phase were compared by different factors, adjusted for disease severity, by using a linear mixed model to account for repeated measurements, assuming a linear increasing trend by days since illness onset. PRNT50 titers were first log-transformed (with base 10). OD, optical density; PRNT50, 50% endpoint plaque reduction neutralization test.
†Effects were adjusted for severity.
1These authors contributed equally to this article.