Updating Reproduction Number Estimates for Mpox in the Democratic Republic of Congo Using Surveillance Data.

Incidence of human monkeypox (mpox) has been increasing in West and Central Africa, including in the Democratic Republic of Congo (DRC), where monkeypox virus (MPXV) is endemic. Most estimates of the pathogen's transmissibility in the DRC are based on data from the 1980s. Amid the global 2022 mpox outbreak, new estimates are needed to characterize the virus' epidemic potential and inform outbreak control strategies. We used the R package vimes to identify clusters of laboratory-confirmed mpox cases in Tshuapa Province, DRC. Cases with both temporal and spatial data were assigned to clusters based on the disease's serial interval and spatial kernel. We used the size of the clusters to infer the effective reproduction number, Rt, and the rate of zoonotic spillover of MPXV into the human population. Out of 1,463 confirmed mpox cases reported in Tshuapa Province between 2013 and 2017, 878 had both date of symptom onset and a location with geographic coordinates. Results include an estimated Rt of 0.82 (95% CI: 0.79-0.85) and a rate of 132 (95% CI: 122-143) spillovers per year assuming a reporting rate of 25%. This estimate of Rt is larger than most previous estimates. One potential explanation for this result is that Rt could have increased in the DRC over time owing to declining population-level immunity conferred by smallpox vaccination, which was discontinued around 1982. Rt could be overestimated if our assumption of one spillover event per cluster does not hold. Our results are consistent with increased transmissibility of MPXV in Tshuapa Province.

Use of Mpox Multiplex Serology in the Identification of Cases and Outbreak Investigations in the Democratic Republic of the Congo (DRC).

Human Mpox cases are increasingly reported in Africa, with the highest burden in the Democratic Republic of Congo (DRC). While case reporting on a clinical basis can overestimate infection rates, laboratory confirmation by PCR can underestimate them, especially on suboptimal samples like blood, commonly used in DRC. Here we used a Luminex-based assay to evaluate whether antibody testing can be complementary to confirm cases and to identify human transmission chains during outbreak investigations. We used left-over blood samples from 463 patients, collected during 174 outbreaks between 2013 and 2022, with corresponding Mpox and VZV PCR results. In total, 157 (33.9%) samples were orthopox-PCR positive and classified as Mpox+; 124 (26.8%) had antibodies to at least one of the three Mpox peptides. The proportion of antibody positive samples was significantly higher in Mpox positive samples (36.9%) versus negative (21.6%) (p < 0.001). By combining PCR and serology, 66 additional patients were identified, leading to an Mpox infection rate of 48.2% (223/463) versus 33.9% when only PCR positivity is considered. Mpox infections were as such identified in 14 additional health zones and 23 additional outbreaks (111/174 (63.8%) versus 88/174 (50.6%)). Our findings highlight the urgent need of rapid on-site diagnostics to circumvent Mpox spread.

Serological responses to the MVA-based JYNNEOS monkeypox vaccine in a cohort of participants from the Democratic Republic of Congo.

The current worldwide monkepox outbreak has reaffirmed the continued threat monkeypox virus (MPXV) poses to public health. JYNNEOS, a Modified Vaccinia Ankara (MVA)-based live, non-replicating vaccine, was recently approved for monkeypox prevention for adults at high risk of MPXV infection in the United States. Although the safety and immunogenicity of JYNNEOS have been examined previously, the clinical cohorts studied largely derive from regions where MPXV does not typically circulate. In this study, we assess the quality and longevity of serological responses to two doses of JYNNEOS vaccine in a large cohort of healthcare workers from the Democratic Republic of Congo (DRC). We show that JYNNEOS elicits a strong orthopoxvirus (OPXV)-specific antibody response in participants that peaks around day 42, or 2 weeks after the second vaccine dose. Participants with no prior history of smallpox vaccination or exposure have lower baseline antibody levels, but experience a similar fold-rise in antibody titers by day 42 as those with a prior history of vaccination. Both previously naïve and vaccinated participants generate vaccinia virus and MPXV-neutralizing antibody in response to JYNNEOS vaccination. Finally, even though total OPXV-specific IgG titers and neutralizing antibody titers declined from their peak and returned close to baseline levels by the 2-year mark, most participants remain IgG seropositive at the 2-year timepoint. Taken together, our data demonstrates that JYNNEOS vaccination triggers potent OPXV neutralizing antibody responses in a cohort of healthcare workers in DRC, a monkeypox-endemic region. MPXV vaccination with JYNNEOS may help ameliorate the disease and economic burden associated with monkeypox and combat potential outbreaks in areas with active virus circulation.

Clinical and Epidemiological Findings from Enhanced Monkeypox Surveillance in Tshuapa Province, Democratic Republic of the Congo During 2011-2015.

BACKGROUND: Monkeypox is a poorly described emerging zoonosis endemic to Central and Western Africa. METHODS: Using surveillance data from Tshuapa Province, Democratic Republic of the Congo during 2011-2015, we evaluated differences in incidence, exposures, and clinical presentation of polymerase chain reaction-confirmed cases by sex and age. RESULTS: We report 1057 confirmed cases. The average annual incidence was 14.1 per 100 000 (95% confidence interval, 13.3-15.0). The incidence was higher in male patients (incidence rate ratio comparing males to females, 1.21; 95% confidence interval, 1.07-1.37), except among those 20-29 years old (0.70; .51-.95). Females aged 20-29 years also reported a high frequency of exposures (26.2%) to people with monkeypox-like symptoms.The highest incidence was among 10-19-year-old males, the cohort reporting the highest proportion of animal exposures (37.5%). The incidence was lower among those presumed to have received smallpox vaccination than among those presumed unvaccinated. No differences were observed by age group in lesion count or lesion severity score. CONCLUSIONS: Monkeypox incidence was twice that reported during 1980-1985, an increase possibly linked to declining immunity provided by smallpox vaccination. The high proportion of cases attributed to human exposures suggests changing exposure patterns. Cases were distributed across age and sex, suggesting frequent exposures that follow sociocultural norms.

A Tale of Two Viruses: Coinfections of Monkeypox and Varicella Zoster Virus in the Democratic Republic of Congo.

Recent enhanced monkeypox (MPX) surveillance in the Democratic Republic of Congo, where MPX is endemic, has uncovered multiple cases of MPX and varicella zoster virus (VZV) coinfections. The purpose of this study was to verify if coinfections occur and to characterize the clinical nature of these cases. Clinical, epidemiological, and laboratory results were used to investigate MPX/VZV coinfections. A coinfection was defined as a patient with at least one Orthopoxvirus/MPX-positive sample and at least one VZV-positive sample within the same disease event. Between September 2009 and April 2014, 134 of the 1,107 (12.1%) suspected MPX cases were confirmed as MPX/VZV coinfections. Coinfections were more likely to report symptoms than VZV-alone cases and less likely than MPX-alone cases. Significantly higher lesion counts were observed for coinfection cases than for VZV-alone but less than MPX-alone cases. Discernible differences in symptom and rash severity were detected for coinfection cases compared with those with MPX or VZV alone. Findings indicate infection with both MPX and VZV could modulate infection severity. Collection of multiple lesion samples allows for the opportunity to detect coinfections. As this program continues, it will be important to continue these procedures to assess variations in the proportion of coinfected cases over time.

Vaccinating against monkeypox in the Democratic Republic of the Congo.

Healthcare-associated transmission of monkeypox has been observed on multiple occasions in areas where the disease is endemic. Data collected by the US Centers for Disease Control and Prevention (CDC) from an ongoing CDC-supported program of enhanced surveillance in the Tshuapa Province of the Democratic Republic of the Congo, where the annual incidence of human monkeypox is estimated to be 3.5-5/10,000, suggests that there is approximately one healthcare worker infection for every 100 confirmed monkeypox cases. Herein, we describe a study that commenced in February 2017, the intent of which is to evaluate the effectiveness, immunogenicity, and safety of a third-generation smallpox vaccine, IMVAMUNE®, in healthcare personnel at risk of monkeypox virus (MPXV) infection. We describe procedures for documenting exposures to monkeypox virus infection in study participants, and outline lessons learned that may be of relevance for studies of other investigational medical countermeasures in hard to reach, under-resourced populations.

Ebola Virus Disease in Pregnancy: Clinical, Histopathologic, and Immunohistochemical Findings.

Here we describe clinicopathologic features of Ebola virus disease in pregnancy. One woman infected with Sudan virus in Gulu, Uganda, in 2000 had a stillbirth and survived, and another woman infected with Bundibugyo virus had a live birth with maternal and infant death in Isiro, the Democratic Republic of the Congo in 2012. Ebolavirus antigen was seen in the syncytiotrophoblast and placental maternal mononuclear cells by immunohistochemical analysis, and no antigen was seen in fetal placental stromal cells or fetal organs. In the Gulu case, ebolavirus antigen localized to malarial parasite pigment-laden macrophages. These data suggest that trophoblast infection may be a mechanism of transplacental ebolavirus transmission.

Evaluation of the GeneXpert for Human Monkeypox Diagnosis.

Monkeypox virus (MPXV), a zoonotic orthopoxvirus (OPX), is endemic in the Democratic Republic of Congo (DRC). Currently, diagnostic assays for human monkeypox (MPX) focus on real-time quantitative polymerase chain reaction (PCR) assays, which are typically performed in sophisticated laboratory settings. Herein, we evaluated the accuracy and utility of a multiplex MPX assay using the GeneXpert platform, a portable rapid diagnostic device that may serve as a point-of-care test to diagnose infections in endemic areas. The multiplex MPX/OPX assay includes a MPX-specific PCR test, OPX-generic PCR test, and an internal control PCR test. In total, 164 diagnostic specimens (50 crusts and 114 vesicular swabs) were collected from suspected MPX cases in Tshuapa Province, DRC, under national surveillance guidelines. The specimens were tested with the GeneXpert MPX/OPX assay and an OPX PCR assay at the Institut National de Recherche Biomedicale (INRB) in Kinshasa. Aliquots of each specimen were tested in parallel with a MPX-specific PCR assay at the Centers for Disease Control and Prevention. The results of the MPX PCR were used as the gold standard for all analyses. The GeneXpert MPX/OPX assay performed at INRB had a sensitivity of 98.8% and specificity of 100%. The GeneXpert assay performed well with both crust and vesicle samples. The GeneXpert MPX/OPX test incorporates a simple methodology that performs well in both laboratory and field conditions, suggesting its viability as a diagnostic platform that may expand and expedite current MPX detection capabilities.

Extended Human-to-Human Transmission during a Monkeypox Outbreak in the Democratic Republic of the Congo.

A >600% increase in monkeypox cases occurred in the Bokungu Health Zone of the Democratic Republic of the Congo during the second half of 2013; this increase prompted an outbreak investigation. A total of 104 possible cases were reported from this health zone; among 60 suspected cases that were tested, 50 (48.1%) cases were confirmed by laboratory testing, and 10 (9.6%) tested negative for monkeypox virus (MPXV) infection. The household attack rate (i.e., rate of persons living with an infected person that develop symptoms of MPXV infection) was 50%. Nine families showed >1 transmission event, and >6 transmission events occurred within this health zone. Mean incubation period was 8 days (range 4-14 days). The high attack rate and transmission observed in this study reinforce the importance of surveillance and rapid identification of monkeypox cases. Community education and training are needed to prevent transmission of MPXV infection during outbreaks.

Human Monkeypox in the Kivus, a Conflict Region of the Democratic Republic of the Congo.

Monkeypox (MPX) is a zoonotic Orthopoxvirus infection endemic in central and western Africa. Human MPX cases occur in the central and northern regions of the Democratic Republic of the Congo (DRC), and this is the first report of confirmed MPX cases in the forested areas of North and South Kivu Provinces, with a detailed epidemiological investigation for one case. The location of each case is within areas predicted to be suitable for MPX virus transmission based on an ecological niche model. Phylogenetic analysis places these viruses in the Congo Basin clade.

Introduction of Monkeypox into a Community and Household: Risk Factors and Zoonotic Reservoirs in the Democratic Republic of the Congo.

An increased incidence of monkeypox (MPX) infections in the Democratic Republic of the Congo was noted by the regional surveillance system in October 2013. Little information exists regarding how MPX is introduced into the community and the factors associated with transmission within the household. Sixty-eight wild animals were collected and tested for Orthopoxvirus. Two of three rope squirrels (Funisciurus sp.) were positive for antibodies to Orthopoxviruses; however, no increased risk was associated with the consumption or preparation of rope squirrels. A retrospective cohort investigation and a case-control investigation were performed to identify risk factors affecting the introduction of monkeypox virus (MPXV) into the community and transmission within the home. School-age males were the individuals most frequently identified as the first person infected in the household and were the group most frequently affected overall. Risk factors of acquiring MPXV in a household included sleeping in the same room or bed, or using the same plate or cup as the primary case. There was no significant risk associated with eating or processing of wild animals. Activities associated with an increased risk of MPXV transmission all have potential for virus exposure to the mucosa.