Two individuals with potential monkeypox virus reinfection

Since 1999, Vaccinia virus (VACV) has been described as a causative agent of bovine vaccinia (BV), a zoonotic disease that occurs mainly in rural areas of Brazil. However, the circulation of VACV in urban environments and its associated burden has been poorly explored. Moreover, the current monkeypox (mpox) outbreak has raised questions regarding the immune status of the worldwide population previous vaccinated against smallpox. Hence, we conducted a cross‐sectional study to better understand the prevalence of anti‐OPV neutralizing antibodies (NA) and related exposure factors in a susceptible urban population of Brazil. A total of 372 individuals were sampled, yielding an overall seroprevalence of 16.9% (CI95% = 13.4–21.1), and antibodies titers ranging from 100 to 800 neutralizing units/mL. The prevalence of NA among individuals potentially vaccinated against smallpox (≥36 years old [yo]) was 24.9% (IC 95% = 19.5–31.2), and among those unvaccinated (<36yo) was 6.7% (IC 95% = 3.7–11.8). Interestingly, contact with horses was pointed out as an exposure factor for the presence of NA, however, the multivariate logistic regression analysis indicated that age ≥36yo and the presence of vaccine take were independently associated with the presence of anti‐OPV NA. Our findings suggest that vulnerable populations could be subclinically exposed to VACV in urban areas, drawing attention to alternative routes of zoonotic VACV exposure. Our data is also important for better strategies to mitigate zoonotic OPV infections mainly among vulnerable populations.

Section: Discussionmentioning

confidence: 96%

Section: Discussionmentioning

confidence: 97%

Low prevalence of anti‐Orthopoxvirus neutralizing antibodies in an urban population of Brazil

Oliveira

Costa

Dutra

et al. 2023

“…Given that the cases of reinfection and breakthrough infection of MPXV among vaccinated individuals, 12–17 potential safety concerns, 18 and risk for lack of effectiveness and relatively low levels of neutralizing antibodies against MPXV induced by JYNNEOS and ACAM2000, 25 it becomes obvious that smallpox vaccines and natural immunity sometimes might fail in providing enough protection against MPXV. Therefore, MPXV vaccines should be based more on specific and designated targets instead on attenuated viruses.…”

Section: Discussionmentioning

confidence: 99%

“…ACAM2000 is a live attenuated vaccine and JYNNEOS is a nonreplicative vaccine based on VACV Ankara strain 10,11 . However, potential safety concerns, cases of reinfection, and breakthrough infection make these two smallpox vaccines far from the medical demand worldwide 12–18 . Therefore, safe, effective, and widely applicable vaccines for MPXV prevention are needed.…”

Section: Introductionmentioning

confidence: 99%

Evaluation and comparison of immune responses induced by two Mpox mRNA vaccine candidates in mice

Yang,

Hu,

Yang

et al. 2023

The epidemic of Mpox virus (MPXV) from May 2022 was once declared as a Public Health Emergency of International Concern by the World Health Organization. Vaccines play an important role in prevention of infectious diseases, and mRNA vaccine technology was proved to be a safe and effective platform with successful application in defense of coronavirus disease 2019. In this study, based on A29L, M1R, A35R, and B6R of MPXV, we developed two MPXV mRNA vaccine candidates, designated as MPXfus and MPXmix. The MPXfus was one‐component, in which these four antigen proteins were linked in tandem by flexible linker and encoded by an individual mRNA as a fusion protein. The MPXmix was multicomponent containing four mRNA, and each mRNA encoded one antigen protein respectively. Mice were immunized with equal quality of MPXfus or MPXmix, delivered by lipid nanoparticles for evaluation and comparison of the immune responses induced by these two MPXV vaccine candidates. Results of immune response analyses indicated that both MPXfus and MPXmix could elicit high‐level of antigen‐specific antibodies and robust cellular immune response in mice. Moreover, results of virus neutralization assays suggested that sera from MPXfus‐ or MPXmix‐immunized mice possessed high neutralizing activities against vaccinia virus. In addition, titers of antigen‐specific antibody, levels of cellular immune response, and activities of neutralizing antibody against vaccinia virus induced by MPXfus and MPXmix presented no significant difference. In summary, this study provides valuable insights for further clinical development of one‐component and multicomponent mRNA vaccine candidates for the prevention of MPXV and other orthomyxoviruses.

“…As of the 31st of August 2023, there were a total of 1,266 laboratory‐detected mpox cases in the Netherlands 10 . Although mpox cases have decreased towards the end of 2022, with few global mpox detections in early 2023, 10 reports of continuous low‐level detection, re‐infections and new clusters highlight the possibility of re‐emergence and warrant the continuous genomic surveillance of hMPXV 22,23 . In this study, we generated and analyzed 158 near‐complete hMPXV genomes (12.4% of nationwide cases) between the 6th of May 2022 and the 15th of August 2023 from six provinces in the Netherlands.…”

Section: Introductionmentioning

confidence: 99%

Circulation, viral diversity and genomic rearrangement in mpox virus in the Netherlands during the 2022 outbreak and beyond

Schuele,

Boter,

Nieuwenhuijse

et al. 2024

Mpox is an emerging zoonotic disease which has now spread to over 113 countries as of August 2023, with over 89,500 confirmed human cases. The Netherlands had one of the highest incidence rates in Europe during the peak of the outbreak. In this study, we generated 158 near‐complete mpox virus (MPXV) genomes (12.4% of nationwide cases) that were collected throughout the Netherlands from the start of the outbreak in May 2022 to August 2023 to track viral evolution and investigate outbreak dynamics. We detected 14 different viral lineages, suggesting multiple introductions followed by rapid initial spread within the country. The estimated evolutionary rate was relatively high compared to previously described in orthopoxvirus literature, with an estimated 11.58 mutations per year. Genomic rearrangement events occurred at a rate of 0.63% and featured a large deletion event. In addition, based on phylogenetics, we identified multiple potential transmission clusters which could be supported by direct source‐ and contact tracing data. This led to the identification of at least two main transmission locations at the beginning of the outbreak. We conclude that whole genome sequencing of MPXV is essential to enhance our understanding of outbreak dynamics and evolution of a relatively understudied and emerging zoonotic pathogen.