No potential conflict of interest relevant to this letter was reported. The authors reply: Campochiaro and Caruso are correct that mention of cardiovascular associations with ankylosing spondylitis and axial spondyloarthritis, including specific conductionsystem lesions and aortic-root lesions, was largely absent from our review of spondyloarthritis. These specific lesions are uncommon and tend to occur late in the disease course, as does the other more common but less specific cardiovascular illness mentioned in their letter. The focus of our article was on early diagnosis and clinical management of the axial disease, and this priority, along with space and citation limitations, precluded our describing specific cardiovascular manifestations. Rudwaleit M, van derRudwaleit and colleagues make the important point that diagnosis in clinical practice cannot be based solely on fulfillment of classification criteria. We tried to make this point in the article, but perhaps our wording conveyed some unintended ambiguity. In order to introduce the new concept of axial spondyloarthritis, we described the classification criteria for this entity proposed by the ASAS in 2009. In discussing this concept, including the critical role of MRI, we referred to this entity as a diagnosis, in the sense of its being a defined medical condition. We did not intend by this to imply that one can rely strictly on these criteria to establish a diagnosis in clinical practice. In fact, we stated explicitly, "These classification criteria have limited use outside the arena of clinical research," to introduce the algorithm (in Fig. 2 of our article) for use in clinical practice.The algorithm itself is a modification of one published by the correspondents and their colleagues, 1 but it was modified specifically to further emphasize the importance of weighing clinical data and post-test probabilities 2 and of applying clinical judgment to the diagnostic process. Moreover, the discussion of MRI findings includes mention of lesions that are not part of the classification criteria but that can be helpful in supporting a diagnosis in clinical practice. Finally, the Summary section in our article reemphasizes the potential difficulty in accurately establishing or ruling out a diagnosis of axial spondyloarthritis, with no mention of criteria. Viral Load Kinetics of MERS Coronavirus InfectionTo the Editor: The outbreak of Middle East respiratory syndrome coronavirus (MERS-CoV) infection in South Korea involved 186 patients and resulted in 38 deaths, with four large hospital outbreaks accounting for 82% of the total cases. 1,2 Here, we report changes in viral load over time in patients with MERS.We included all patients who were admitted to three Seoul National University-affiliated hospitals; the institutional review boards of these hospitals approved this study and waived the need for written informed consent on public health grounds. The patients were categorized into a group with severe disease (severe group) or a group with mild disease (mild grou...

Middle East Respiratory Syndrome coronavirus (MERS-CoV) was first isolated from a patient with severe pneumonia in 2012. The 2015 Korea outbreak of MERSCoV involved 186 cases, including 38 fatalities. A total of 83% of transmission events were due to five superspreaders, and 44% of the 186 MERS cases were the patients who had been exposed in nosocomial transmission at 16 hospitals. The epidemic lasted for 2 months and the government quarantined 16,993 individuals for 14 days to control the outbreak. This outbreak provides a unique opportunity to fill the gap in our knowledge of MERS-CoV infection. Therefore, in this paper, we review the literature on epidemiology, virology, clinical features, and prevention of MERS-CoV, which were acquired from the 2015 Korea outbreak of MERSCoV.

We investigated the kinetics of severe acute respiratory syndrome coronavirus 2 neutralizing antibodies in 7 asymptomatic persons and 11 patients with pneumonia. The geometric mean titer of neutralizing antibodies declined from 219.4 at 2 months to 143.7 at 5 months after infection, indicating a waning antibody response.

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