Clinical, epidemiological, and virological features of Mpox in Beijing, China – May 31–June 21, 2023

Figures & data

Figure 1. Onset and report time of Mpox cases in Beijing between May 31, 2023 and June 21, 2023.

Note: 37 Mpox cases are included in A and 33 symptomatic cases of Mpox are included in B.

Table 1. Demographics, medical history, and exposure travel information among confirmed Mpox cases of Beijing, China as of June 21, 2023.

Characteristics	Patients(N = 37)
District of Mpox case residence
Chaoyang	20 (54.1%)
Tongzhou	7 (18.9%)
Xicheng	2 (5.4%)
The others(each reported one)	8 (21.6%)
Median age, years(IQR)	30, (26.5–34.5)
Age group, years
24–	16(43.3%)
30–	12(32.4%)
35–	3(8.1%)
40–	3(8.1%)
45–	3(8.1%)
History of smallpox vaccine	3 (8.1%)
Sexual orientation
Homosexual	34 (91.9%)
Bisexual	2 (5.4%)
Heterosexual	1 (2.7%)
HIV-positive	19 (51.4%)
Standardized Antiretroviral Therapy	11 (57.8%)
Newly diagnosed	1 (5.3%)
Irregular treatment	1 (5.3%)
Information not provided	6 (31.6%)
Syphilis infections
Past infection	12 (32.4%)
Newly diagnosed	1 (2.7%)
Recent negative test results	10 (27.0%)
No relevant information provided	14 (37.9%)
Travel abroad 21 days before onset	3 (8.1%)

IQR, interquartile range. Data are shown as n (%), unless otherwise indicated.

Table 2. Clinical characteristics of Mpox cases.

Signs and symptoms	Patients (N = 33)
Fever (subjective or measured)	26 (78.8%)
37°C–	7/26 (26.9%)
38°C–	9/26 (34.6%)
39°C–	7/26 (26.9%)
Not measured	3/26 (11.6%)
Rash or skin lesions anywhere on the body#	32(97.0%)
Rash on and around the genitals	26 (78.8%)
Rash perianal	5 (15.2%)
Rash on the face	7 (21.2%)
Rash on the limbs	12 (36.4%)
Rash on the torso	7 (21.2%)
Enlarged and painful lymph nodes#	17 (51.5%)
Inguinal lymph nodes	16 (48.5%)
Submandibular lymph nodes	2 (6.1%)
Order of fever and rash
Fever without skin rash	1 (3.0%)
Rash without fever	7 (21.2%)
Rash preceding fever	11 (33.3%)
Rash following fever	13 (39.4%)
Fever and rash on the same day	1 (3.0%)
Chief complaint during the first outpatient visit
Fever only	3/28 (10.7%)
Rash only	11/28 (39.3%)
Fever and rash	4/28 (14.3%)
Lymph node swelling and pain	2/28 (7.1%)
Ruling out sexually transmitted infections (STIs)	8/28 (28.6%)
Chief complaint leading to Mpox diagnosing
Genital or perigenital skin rash	21/28 (75.0%)
Perianal rash	3/28 (10.8%)
Limb, cranial, or torso rash	2/28 (7.1%)
Genital redness and swelling or ulcers	2/28 (7.1%)

Note: Data are shown as n (%) or n/N (%), unless otherwise indicated.

#: The percentages in the table represent the symptom occurrence rate, which may exceed 100% when added together.

Table 3. Positive rates for different specimen types in Mpox cases.

Specimen types	Number of specimens	Positive Rate N(%)	Ct value, Median (Interquartile Range)
Mpox symptomatic cases
Vesicular or pustular fluid	11	11 (100.0)	18 (16–22)
Skin lesion swab	18	18 (100.0)	21 (18–25)
Scabs	4	4 (100.0)	25 (16–36)
Oropharyngeal swab	33	25 (75.8)	30 (27–34)
Blood	26	22 (84.6)	35 (32–36)
Rectal swab or perianal swab	6	5 (83.3)	30 (17–36)
The asymptomatic infected individuals
Rectal swab or perianal swab	4	2 (50%)	36, 37#
Oropharyngeal swab	4	2 (50%)	24, 37#

#There were only two positive specimens, with the corresponding Ct values provided

Figure 2. Phylogenetic tree based on the genome sequences of the Mpox virus.

Note: Phylogenetic analysis of 29 local strains and 2 imported strains in Beijing, 2023. Different-colored branch names represent the different lineages. The black circles indicate bootstrap values of >90%, and the grey circles indicate bootstrap values of >70% and <90%. The red triangles indicate local strains and the blue stars indicate imported strains.