Figure 1Epidemiologic curve of 178 confirmed cases of Middle East respiratory syndrome coronavirus (MERS-CoV) infection in the Republic of Korea, 2015. Panel A (integrated curve) depicts the overall epidemiologic curve by date of symptom onset. Red color indicates the index patient, and three main clusters (Hospital C, Hospital H, and Hospital M and N) are depicted with yellow, green, and purple, respectively. Eight cases whose date of symptom onset is uncertain or who are still under investigation are excluded. Panel B shows the epidemic curve of each of the three main clusters. Stages of transmission are expressed by different patterns. An additional case in Hospital H whose stage of transmission is uncertain is excluded.
Figure 2Incubation period of Middle East respiratory syndrome coronavirus (MERS-CoV) infection outbreak in the Republic of Korea, 2015. Panel A shows the density estimation of incubation periods with gamma distribution. Panel B shows the empirical cumulative density estimation of incubation period.
Figure 3Serial interval of Middle East respiratory syndrome coronavirus (MERS-CoV) infection outbreak in the Republic of Korea, 2015. Panel A shows the density estimation of serial intervals using gamma distribution. Panel B shows the empirical cumulative density estimation of serial intervals.
Figure 4Transmission map of 182 confirmed cases of Middle East respiratory syndrome coronavirus (MERS-CoV) infection in the Republic of Korea. The numbers within the red circles are identifiers of notable patients who caused succeeding MERS-CoV infection. The site and the duration of exposure by these patients are indicated in colored boxes. Gray boxes depict the time periods that new cases occurred by date of symptom onset at each site. Black arrows represent how each spreader moved to the next site of transmission. The transmission route of Patient 119 is uncertain. Four cases still under investigation are excluded.
Figure 5Evolutionary history of the Middle East respiratory syndrome coronavirus (MERS-CoV). A phylogenetic tree was constructed using RAxML. The scale bar shows evolutionary distance inferred by RAxML algorithm. The MERS-CoV in the Republic of Korea outbreak is indicated by a red cycle. Support for the ML phylogenetic trees was evaluated using 1,000 bootstrap replicates. Note numbers represent % bootstrap replicates >70%.
Table 1Demographic and clinical features of 186 cases of laboratory-confirmed Middle East respiratory syndrome coronavirus (MERS-CoV) infection, Republic of Korea, 2015.
Characteristics |
No. of patients |
Sex, n (%) |
Male |
111 (59.7) |
Female |
75 (40.3) |
Age (y), median (IQR) |
55 (42–66) |
≥65y, n (%) |
55 (29.6) |
Case classification, n (%) |
Healthcare personnel |
25 (13.4) |
Patient |
82 (44.1) |
Caregiver |
61 (32.8) |
Others∗
|
18 (9.7) |
Symptoms at presentation, n (%) |
Fever/chills |
138 (74.2) |
Cough |
33 (17.7) |
Dyspnea |
10 (5.4) |
Myalgia |
47 (25.3) |
Headache |
16 (8.6) |
GI symptoms†
|
24 (12.9) |
Sputum |
14 (7.5) |
Sore throat |
8 (4.3) |
Comorbidities, n (%) |
Any‡
|
102 (54.8) |
Respiratory disease§
|
23 (12.4) |
Diabetes mellitus |
52 (28.0) |
Cardiac disease∥
|
42 (22.6) |
Chronic kidney disease |
9 (4.8) |
Malignancy |
43 (23.1) |
Known setting of contact, n (%)¶
|
Healthcare facility |
178 (98.0) |
Household |
1 (0.5) |
Ambulance |
3 (1.5) |
Time from symptom onset to laboratory confirmation in days, median (IQR) |
5 (3–9) |
Time from symptom onset to death in days, median (IQR) |
15 (10–20) |
Outcome as of July 13, 2015, n (%) |
|
Recovered |
131 (70.4) |
Ongoing treatment in hospital |
19 (10.2) |
Died |
36 (19.4) |
Table 2Characteristics of superspreaders of Middle East respiratory syndrome coronavirus infection outbreak in the Republic of Korea, 2015.
Patient number |
1 |
14 |
15 |
16 |
76 |
Infected no. of patients |
28 |
85 |
6 |
23 |
11 |
Age (y) |
68 |
35 |
35 |
41 |
75 |
Sex |
Male |
Male |
Male |
Male |
Female |
Body mass index |
27 |
30 |
24 |
24 |
19 |
Underlying disease |
Hypertension, asthma |
No |
No |
Familial adenomatous polyposis |
Diabetes mellitus, multiple myeloma |
Exposed duration (d)∗
|
10 |
9 |
10 |
11 |
2 |
Exposed setting |
GW (27 cases) OPD (1 case) |
ER (78 cases) GW (4 cases) Other (3 cases) |
GW (6 cases) |
GW (22 cases) Other (1 case) |
ER (4 cases) GW (3 cases) Other (4 cases) |
Number of close contacts |
626 |
594 |
304 |
277 |
805 |
Personal protective equipment |
No |
Intermittent |
No |
No |
No |
Pneumonia†
|
Present |
Present |
Present |
Present |
Present |
Cough |
Frequent |
Frequent |
Rare |
Frequent |
Rare |
Prognosis |
Survived |
Survived |
Survived |
Survived |
Expired |
Aerosol-generating procedure |
No |
No |
No |
No |
No |
Table 3Risk factors associated with in-hospital mortality in 186 patients with laboratory-confirmed Middle East respiratory syndrome coronavirus (MERS-CoV) infection, 2015.
Variable |
Univariate logistic regression
|
Multivariate logistic regression
|
OR |
95%CI |
p
|
OR |
95%CI |
p
|
Sex, male |
1.44 |
0.67–3.11 |
0.434 |
1.56 |
0.62–3.91 |
0.33 |
Age, ≥ 65 y |
7.67 |
3.45–17.04 |
<0.0001 |
4.86 |
1.90–12.45 |
0.001 |
Case classification, patient |
3.17 |
1.47–6.83 |
0.003 |
0.82 |
0.27–2.50 |
0.73 |
Respiratory disease∗,†
|
6.27 |
2.48–15.83 |
<0.0001 |
4.90 |
1.64–14.65 |
0.004 |
Diabetes mellitus |
2.91 |
1.436–6.20 |
0.006 |
1.37 |
0.55–3.45 |
0.49 |
Cardiac disease†
|
4.43 |
2.02–9.70 |
<0.0001 |
2.21 |
0.86–5.67 |
0.09 |
Chronic kidney disease |
5.84 |
1.48–23.0 |
0.012 |
2.30 |
0.44–11.94 |
0.32 |
Malignancy |
2.63 |
1.20–5.76 |
0.015 |
1.92 |
0.75–4.86 |
0.16 |