Comparative evaluation of the clinical presentation and epidemiology of the 2022 and previous Mpox outbreaks: a rapid review and meta-analysis

Clinical features and viral load variations of Mpox: a retrospective study in Chongqing, China

PURPOSE

Since May 2022, Mpox has spread extensively outside of Africa, posing a serious threat to the health of people globally, and particularly to the men who have sex with men (MSM) population. Chongqing, a province in Southwest China, has relatively large MSM and people living with HIV (PLWH) populations, presenting conditions conducive to the wide dissemination of Mpox. In this study, we investigated the clinical characteristics of Mpox patients among MSM and PLWH in Chongqing, aiming to inform the development of targeted prevention, control, and treatment strategies for Mpox.

METHOD

We evaluated the clinical characteristics, travel history, time of onset, distribution and number of skin lesions of Mpox patients admitted to the Chongqing Public Health Medical Center between September 2022 and October 2023. Meanwhile, a series of clinical samples were collected and the pathogen of interest was identified as Mpox virus using quantitative polymerase chain reaction (qPCR). The results were presented in the form of cycle thresholds (Ct), which help to approximate the quantification of viral load.

RESULTS

As of October 11, 2023, the Chongqing Public Health Medical Center reported a total of nine Mpox virus infections. All the patients identified were male and belonged to the MSM population, among whom seven (77.8%) were living with HIV, and maintained a preserved immune system while achieving viral suppression via effective ART. We observed no discernible clinical differences between MSM with Mpox with or without HIV, and no fatalities were recorded. Viral loads were observed to be higher in samples taken from the skin than those from the throat, nasopharynx, blood, or semen.

CONCLUSION

In this retrospective study, the clinical manifestations of MPXV infection appeared consistent among MSM patients, regardless of HIV status. Elevated MPXV viral loads in the skin and mucosal tissues, particularly at genital and anal sites, indicate that transmission is more likely to occur via direct physical contact as opposed to respiratory pathways or through exposure to bodily fluids.

A global systematic evidence review with meta-analysis of the epidemiological characteristics of the 2022 Mpox outbreaks

BACKGROUND

In 2022, there were outbreaks of Mpox where the disease is not endemic. We summarized published full-text epidemiological data from the outbreaks.

METHODS

A global evidence review (protocol: osf.io/j3kb7) with systematic literature search up to February 09, 2023. We focused on experimental/observational studies of laboratory confirmed Mpox, excluding case reports and case series of < 5 cases. Epidemiological data were pooled using an inverse variance, random-effects model, and pooled estimates presented with associated 95% confidence intervals.

RESULTS

We included 66 studies. Mean incubation period was 7.8 days (6.6-9.0 days, 8 studies: 560 cases), reproductive number 1.8 (1.7-1.9, 6 studies), mean duration from symptom onset to diagnosis 5.8 days (4.8-6.8 days, 4 studies: 982 cases), mean symptom duration 17.5 days (14.7-20.2 days, 3 studies: 292 cases), mean serial interval 8.5 days (7.3-9.9 days, 1 study), hospitalisation 6% (4-9%, 26 studies: 5339 cases), and vaccine effectiveness 78% (65-91%, 3 studies: 953 cases). Highly relevant clinical manifestations were pleomorphic skin lesions 82% (68-94%, 26 studies: 4093 cases), anogenital lesions 64% (51-77%, 9 studies: 10,398 cases), fever 54% (50-57%, 52 studies: 25,992 cases), and lymphadenopathy 51% (46-57%, 42 studies: 17,803 cases), with cases mostly men who have sex with men (MSM). Possibly relevant manifestations were perianal lesions, fatigue, asthenia, myalgia, and headache.

CONCLUSIONS

The 2022 Mpox outbreaks presented with sex-related clinical manifestations and were mostly reported among MSM.

Clinical Features of Mpox Patients in Korea: A Multicenter Retrospective Study

BACKGROUND

Mpox is a viral illness with a characteristic skin rash caused by the monkeypox virus. In 2022, Mpox spread throughout the world, and an epidemic through domestic transmission started in South Korea in early 2023. This study aimed to summarize the clinical features of Mpox patients in South Korea.

METHODS

This is a multicenter retrospective study conducted at four hospitals in South Korea. All adult patients diagnosed with Mpox who were admitted to the study hospitals between June 1, 2022 and May 26, 2023 and were discharged by June 30, 2023 were reviewed.

RESULTS

Sixty patients were included, accounting for 65.9% of Mpox cases reported in South Korea during the study period. Median age was 32 years and 97% (58/60) of patients were male. In total, 85% (51/60) of patients reported their sexual orientation as homosexual or bisexual. The most common route of transmission was sexual or close contact (55/60). Every patient had a skin rash and 88% (53/60) had constitutional symptoms. In total, 42% (25/60) of patients had human immunodeficiency virus and 25% (15/60) had concomitant sexually transmitted infections. Severe manifestations of Mpox were identified in only two patients.

CONCLUSION

Mpox patients in South Korea were mainly young adult males and were infected through sexual contact. The clinical outcomes were favorable.

Clinical characteristics and predictors of human mpox outcome during the 2022 outbreak in Nigeria: a cohort study

BACKGROUND

Research from sub-Saharan Africa that contributes to our understanding of the 2022 mpox (formerly known as monkeypox) global outbreak is insufficient. Here, we describe the clinical presentation and predictors of severe disease among patients with mpox diagnosed between Feb 1, 2022, and Jan 30, 2023 in Nigeria.

METHODS

We did a cohort study among laboratory-confirmed and probable mpox cases seen in 22 mpox-treatment centres and outpatient clinics across Nigeria. All individuals with confirmed and probable mpox were eligible for inclusion. Exclusion criteria were individuals who could not be examined for clinical characterisation and those who had unknown mortality outcomes. Skin lesion swabs or crust samples were collected from each patient for mpox diagnosis by PCR. A structured questionnaire was used to document sociodemographic and clinical data, including HIV status, complications, and treatment outcomes from the time of diagnosis to discharge or death. Severe disease was defined as mpox associated with death or with a life-threatening complication. Two logistic regression models were used to identify clinical characteristics associated with severe disease and potential risk factors for severe disease. The primary outcome was the clinical characteristics of mpox and disease severity.

FINDINGS

We enrolled 160 people with mpox from 22 states in Nigeria, including 134 (84%) adults, 114 (71%) males, 46 (29%) females, and 25 (16%) people with HIV. Of the 160 patients, distinct febrile prodrome (n=94, 59%), rash count greater than 250 (90, 56%), concomitant varicella zoster virus infection (n=48, 30%), and hospital admission (n=70, 48%) were observed. Nine (6%) of the 160 patients died, including seven (78%) deaths attributable to sepsis. The clinical features independently associated with severe disease were a rash count greater than 10 000 (adjusted odds ratio 26·1, 95% CI 5·2-135·0, p<0·0001) and confluent or semi-confluent rash (6·7, 95% CI 1·9-23·9). Independent risk factors for severe disease were concomitant varicella zoster virus infection (3·6, 95% CI 1·1-11·5) and advanced HIV disease (35·9, 95% CI 4·1-252·9).

INTERPRETATION

During the 2022 global outbreak, mpox in Nigeria was more severe among those with advanced HIV disease and concomitant varicella zoster virus infection. Proactive screening, management of co-infections, the integration and strengthening of mpox and HIV surveillance, and preventive and treatment services should be prioritised in Nigeria and across Africa.

FUNDING

None.