A total of 43 patients were enrolled in the study, with a median age of 32.0 years and an age range of 19 to 64 years. Two participants were women (4.7%) and 41 (95.3%) were men, all of whom self-identified as MSM. Among the patients, 10 (23.3%) were HIV-positive and under effective antiretroviral therapy, while 33 (76.7%) were HIV-negative. Of the HIV-negative patients, 23 (69.7%) were using HIV pre-exposure prophylaxis (PrEP). One patient suffered from a chronic lung disease and one from diabetes. Two patients were iatrogenically immunosuppressed due to multiple sclerosis and psoriasis, receiving fingolimod and an anti-IL-17 antibody, respectively.
Only four patients (9.3%) were vaccinated against smallpox in their childhood, and none had recently been vaccinated against MPXV. It is worth noting that the modified vaccinia virus vaccination against mpox was not available in Germany until July 2022 [13].
The incubation period from the suspected event of infection until the onset of general symptoms was 7.5 days (median, Q1-Q3: 6.8–14.3). The median incubation period until the appearance of the first skin lesions was 9.0 days (Q1-Q3: 6.0–15.0). The median time between the first appearance of skin symptoms and a confirmed diagnosis by PCR was 5.0 days (Q1-Q3: 1.5–10.0). If hospitalization was necessary, the median duration of the hospital stay was 5.0 days (Q1-Q3: 4.0–6.0). Table 1 illustrates the epidemiological data on the course of the disease.
Characteristics of acute infection
The most common clinical symptoms during the acute infection were visible skin or mucosal lesions (40 out of 43 patients, 93.0%), lymphadenopathy (26/30, 86.6%) and fever (21/30, 70.0%). Overall, the patients presented with a median number of 6.5 skin lesions (Q1-Q3: 3.3–10.0, range: 0-200), although one patient under fingolimod treatment had 200 lesions [14].
Among the 30 patients who responded to these questions, pain was reported by 22 (73.3%), with a median pain NRS score of 8 (Q1-Q3: 6.0–10.0). Itching was observed in 20 patients (20/29, 69.0%), with a median itch NRS score of 6.5 (Q1-Q3: 4.3-8.0). Table 2 provides an overview of clinical characteristics during the acute infection.
Compared to genital localization, lesions in the anal area and in the mouth or throat were associated with a significantly higher proportion of pain (RR 3.60, 95%-CI 1.48–8.74; RR 2.83, 95%-CI 1.07–7.50, respectively). Itching was reported significantly more frequently only in the anal area (RR 2.94, 95%-CI 1.16–7.46), but not in the throat or mouth (Table 3).
Complications were reported in 20 (46.5%) patients (see Table 4), with 15 cases of either superinfection and/or the formation of abscesses. Of the 43 patients included in our cohort, 20 (46.5%) required hospitalization, mostly due to pain (n = 20) and/or superinfection (n = 10) or abscesses (n = 5). No fatalities were reported in this study.
Although not statistically significant, a notable association (RR 1.78, 95%-CI 0.99–3.19, p = 0.109) was observed between the HIV status of patients and the occurrence of complications (Table 5). Among the ten patients with known HIV infection, 70.0% (7/10) experienced complications, while only 39.4% (13/33) of the HIV-negative patients were affected. It is noteworthy that we did not detect any previously unknown HIV infections and that all patients with known HIV infections were receiving appropriate and effective antiretroviral therapy.
The patients were provided with best supportive care as part of their treatment. Among the therapeutic measures administered, local antiseptics were used in 84.2% (32/38) of cases, while systemic antibiotic treatment was given to 65.9% (27/41) of patients. Analgesic medication was administered to all individuals, with 13.9% (5 out of 36) requiring intravenous administration. Access to tecovirimat, an mpox-specific antiviral drug, was severely limited in Germany in summer 2022. As none of the patients was critically ill, tecovirimat was not administered.
Sequelae at 4-6-month follow-up
Nineteen of 43 patients (44.2%) were available for the follow-up visits at 4 to 6 months after the acute infection. Of these, 16 patients (84.2%) had residual skin lesions. Scarring was generally rated to be minimal by both patients (PSAS median: 14.0, Q1-Q3: 9.8–27.0) and observers (OSAS median: 13.5, Q1-Q3: 9.3–19.8). While 12 out of 19 patients (63.2%) reported no residual impairment due to their mpox disease at all, 2 out of 17 patients (11.8%) reported still having pain. Considering the overall sample, the DLQI was found to be low, with a median score of 1.0 (Q1-Q3: 0-2.5) (Table 6), indicating no significant impact on overall QoL. Likewise, general impairment (median: 0.0, Q1-Q3: 0–2), sexual impairment (median: 0.0, Q1-Q3: 0–5) and pain (median: 0.0, Q1-Q3: 0–0) were low (Table 6). Six patients (35.3%) reported a DLQI score of 0.0, and 10 patients (52.6%) experienced no sexual impairment at all.
However, comparing patients who had an abscess or bacterial superinfection during the acute phase with patients who did not experience such complications, revealed significant differences: Patients with bacterial superinfection or abscess during the acute phase had more intense scarring than those without these complications (median PSAS 24.0 vs. 11.0, p = 0.039; median OSAS 18.5 vs. 11.0, p = 0.059). Accordingly, these patients also suffered from significantly greater limitations in their quality of life and sexuality (median DLQI: 2.0 vs. 0.0, p = 0.036; median sexual impairment NRS: 5.0 vs. 0.0, p = 0.017) (Table 6).