Prevalence of Asymptomatic Mpox among Men Who Have Sex with Men, Japan, January-March 2023

Discordant performance of mpox serological assays

BACKGROUND

Since July 23, 2022, global mpox cases reached 92,546, with over 31,000 in the United States. Asymptomatic carriage is a critical mechanism influencing the global dissemination of mpox. Seroprevalence studies are crucial for determining the epidemic's true burden, but uncertainties persist in serologic assay performance and how smallpox vaccination may influence assay interpretation.

OBJECTIVES

Our study aimed to assess the performance of several diagnostic assays among mpox-positive, vaccinated, and pre-outbreak negative control samples. This investigation sought to enhance our understanding and management of future mpox outbreaks.

STUDY DESIGN

Serum samples from 10 mpox-positive, five vaccinated uninfected, and 137 pre-outbreak controls were obtained for serological testing. The mpox-positive samples were obtained around 100 days post symptom onset, and vaccinated patients were sampled approximately 90 days post-vaccination. Multiple diagnostic assays were employed, including four commercial ELISAs (Abbexa, RayBioTech, FineTest, ProteoGenix) and a multiplex assay (MesoScale Diagnostics (MSD)) measuring five mpox and five smallpox antigens.

RESULTS

Three commercial ELISA kits had low specificity (<50 %). The Proteogenix ELISA targeting the E8L antigen had a 94 % sensitivity and 87 % specificity. The E8L antigen on the MSD assay exhibited the greatest distinction between exposure groups, with 98 % sensitivity and 93 % specificity.

CONCLUSIONS

None of the assays could distinguish between mpox-positive and vaccinated samples. The MSD assay targeting the MPXV E8L antigen demonstrated the greatest differentiation between mpox-positive and pre-outbreak negative samples. Our findings underscore the imperative to identify sensitive and specific assays to monitor population-level mpox exposure and infection.

Prevention of sexual transmission of mpox: a systematic review and qualitative evidence synthesis of approaches

BACKGROUND

The ongoing multi-country mpox outbreak in previously unaffected countries is primarily affecting sexual networks of men who have sex with men. Evidence is needed on the effectiveness of recommended preventive interventions. To inform WHO guidelines, a systematic review and qualitative evidence synthesis were conducted on mpox preventive behavioural interventions to reduce: (i) sexual acquisition; (ii) onward sexual transmission from confirmed/probable cases; and (iii) utility of asymptomatic testing.

METHODS

Medline, EMBASE, PubMed, Cochrane and WHO trial databases, grey literature and conferences were searched for English-language primary research published since 1 January 2022. A reviewer team performed screening, data extraction and bias assessment. A qualitative thematic synthesis explored views and experiences of engagement in prevention in individuals at increased risk.

RESULTS

There were 16 studies: 1 on contact-tracing, 2 on sexual behaviour, and 13 on asymptomatic testing. Although MPXV was detected in varying proportions of samples (0.17%-6.5%), the testing studies provide insufficient evidence to fully evaluate this strategy. For the qualitative evidence synthesis, four studies evaluated the experiences of most affected communities. Preferences about preventive interventions were shaped by: mpox information; the diversity of sexual practices; accessibility and quality of mpox testing and care; and perceived cost to wellbeing.

CONCLUSIONS

Evidence on the effectiveness of interventions to prevent the sexual transmission of mpox remains scarce. Limited qualitative evidence on values and preferences provides insight into factors influencing intervention acceptability. Given global and local inequities in access to vaccines and treatment, further research is needed to establish the effectiveness of additional interventions.

Mpox in people with HIV: A narrative review

OBJECTIVE

The 2022 global mpox outbreak disproportionately impacted people living with HIV. This review explores recent evidence on mpox in this group, focusing on clinical presentation, complications, treatment modalities and vaccine strategies.

RECENT FINDINGS

Recent studies have suggested that people with HIV diagnosed with mpox have a greater risk of proctitis and hospitalization compared with people without HIV. In addition, those with advanced immunosuppression face an elevated risk of severe mpox infection, which can lead to mortality. Comprehensive and prompt supportive care using antiretrovirals and mpox antivirals is crucial in this group. Although results from randomized clinical trials are still forthcoming, recent studies suggest that early initiation of tecovirimat can prevent disease progression in people with HIV. The non-replicative attenuated smallpox vaccine is well tolerated and effective in preventing monkeypox virus infections in people with HIV. Further studies are needed regarding long-term vaccine effectiveness for this population.

CONCLUSION

Evaluating the risk of severe mpox in people living with HIV requires assessing the level of immune suppression and viral control. Universal access to vaccination is imperative to prevent the resurgence of future outbreaks.

Clinically inapparent mpox virus (MPXV) infections among clients of three anonymous Community Based Voluntary Counselling and Testing centres in Berlin, Germany, 2022-2023

INTRODUCTION

Since the mpox outbreak in 2022, it was unclear if and how often infections with mpox virus (MPXV) were clinically inapparent, i.e. not presenting to clinical care with mpox symptoms. Moreover, it was hypothesized that MPXV circulated in the affected communities before the outbreak was officially detected.

METHODS

We retrospectively tested rectal and urethral swabs, and pooled samples for presence of MPXV. Samples were obtained from routine STI testing of three anonymous Community Based Voluntary Counselling and Testing (CBVCT) centres in Berlin, in 2022 and 2023. Testing results were linked to anonymously provided behavioural data.

RESULTS

Overall, 9,053 samples from 6,600 client visits were included. Clinically inapparent MPXV infections were detectable in 1.1% of the samples. We did not find MPXV infections in the month before the first cases appeared in Berlin or between October 2022 and January 2023 when case numbers were low in Germany. However, during the outbreak period in 2022, we found clinically inapparent MPXV infections among 2.2% of the clients and during summer/autumn 2023 among 0.3%. The number of condomless anal/vaginal intercourse partners within the previous 6 months and PrEP use were identified as predictors of clinically inapparent MPXV infection.

CONCLUSION

Clinically inapparent MPXV infections occurred during the mpox outbreak in Berlin in 2022 and post-outbreak in summer/autumn 2023. Unrecognized MPXV circulation in Berlin before the recognition of the outbreak in May 2022 appears unlikely. However, low-level sustained circulation of clinically inapparent MPXV infections need to be acknowledged in mpox prevention strategies.

Crisis management for the future: Building a platform to provide information on emerging and re-emerging infectious diseases from normal times in Japan

At the beginning of the mpox (disease caused by monkey pox) epidemic, there was no platform in Japan to provide appropriate information on emerging and re-emerging infectious diseases (EIDs), and the number of accesses to bioterrorism-related information sites increased rapidly. Even though the interest in mpox was much smaller than in coronavirus infectious disease, emerged in late 2019 (COVID-19), the increase in the number of views were much greater than during the COVID-19 epidemic. This may not be because mpox is bioterrorism-related as an analog of smallpox, but rather because there were no other websites providing information on mpox. For future crisis management, there should be a platform to provide information on possible epidemics of EIDs from normal times in Japan.

Multiple introductions of monkeypox virus to Ireland during the international mpox outbreak, May 2022 to October 2023

BackgroundMpox, caused by monkeypox virus (MPXV), was considered a rare zoonotic disease before May 2022, when a global epidemic of cases in non-endemic countries led to the declaration of a Public Health Emergency of International Concern. Cases of mpox in Ireland, a country without previous mpox reports, could reflect extended local transmission or multiple epidemiological introductions.AimTo elucidate the origins and molecular characteristics of MPXV circulating in Ireland between May 2022 and October 2023.MethodsWhole genome sequencing of MPXV from 75% of all Irish mpox cases (182/242) was performed and compared to sequences retrieved from public databases (n = 3,362). Bayesian approaches were used to infer divergence time between sequences from different subclades and evaluate putative importation events from other countries.ResultsOf 242 detected mpox cases, 99% were males (median age: 35 years; range: 15-60). All 182 analysed genomes were assigned to Clade IIb and, presence of 12 distinguishable subclades suggests multiple introductions into Ireland. Estimation of time to divergence of subclades further supports the hypothesis for multiple importation events from numerous countries, indicative of extended and sustained international spread of mpox. Further analysis of sequences revealed that 92% of nucleotide mutations were from cytosine to thymine (or from guanine to adenine), leading to a high number of non-synonymous mutations across subclades; mutations associated with tecovirimat resistance were not observed.ConclusionWe provide insights into the international transmission dynamics supporting multiple introductions of MPXV into Ireland. Such information supported the implementation of evidence-informed public health control measures.

The prevalence of mpox and its association with sexual behavior among Chinese men who have sex with men in early August 2023

Study investigating mpox infection and its association with sexual behavior among men who have sex with men (MSM) in China was lacking. This observational survey aimed to provide evidence on detail characteristics of mpox cases and sexual behavior, then analyze their relationship among MSM in China to help formulate prevention and control policies. An anonymous cross-sectional study was conducted in 27 MSM social organizations across 21 provinces, municipalities, and autonomous regions from July 31 to August 4, 2023. A safe sexual behavior index was constructed based on three risky sexual behaviors in the last month, including condomless anal intercourse, commercial sex and group sex. High safe sexual behavior indicated that the participant engaged in none of the three, and low safe sexual behavior indicated that they engaged in all three behaviors; otherwise, moderate safe sexual behavior was indicated. Among 7538 MSM, the prevalence of mpox was 0.73% (55/7538). The proportion of high safe sexual behavior was 79.64% (6003/7538). The crude prevalence of mpox was lower in the high safe sexual behavior group (0.35%, 21/6003), compared with the low (12.12%, 8/66) and moderate safe (1.78%, 26/1469) sexual behavior group. In the multivariable-adjusted analysis, after adjusting for all covariates, compared with low safe sexual behavior group, moderate safe sexual behavior group (aOR = 0.21; 95% CI = 0.08, 0.54) and high safe sexual behavior group (aOR = 0.04; 95% CI = 0.02, 0.12) both had lower risk of mpox. Of three sexual behaviors, MSM who reported no commercial sex had the lowest risk of mpox (aOR = 0.23; 95% CI = 0.13, 0.41), compared with those who reported commercial sex in the last month. The other two safe sexual behaviors both were associated with lower risk of mpox (no group sex vs. group sex: aOR = 0.15; 95% CI = 0.08, 0.28; no condomless anal intercourse vs. condomless anal intercourse: aOR = 0.23; 95% CI = 0.13, 0.41). The prevalence of mpox virus infection was nearly 1% among MSM in China. Strengthening mpox surveillance, emphasizing safe sexual behavior in health education are essential for the control of mpox among MSM in China.