The monkeypox virus (MPXV), called so because of its first discovery in monkeys kept in research facility in Denmark, is closely related to variola virus that causes smallpox. It is responsible for monkeypox (mpox) disease that has gradually emerged in Africa following eradication of smallpox and cessation of smallpox vaccination. It has two clades: clade I and clade II. The clade II has two subclades. The epidemic of 2022 is attributed to the subclade IIb. The rapid outbreak of October 2023 in the Kamituga region of the DR Congo was found to have transmitted through sexual contact and was attributed to a distinct MPXV Clade Ib lineage of recent human-to-human transmission. There has been upsurge of mpox cases in the DR Congo and in many other countries in Africa. Many European countries also have reported continuously increasing number of monkeypox infections since May 2022.
In view of emergence of new strains with higher transmissibility and virulence, rapidly evolving epidemiology across countries in the region, and the severity in children and immunocompromised individuals, the IHR (International Health Regulations, 2005) Emergency Committee, in its first meeting of held on 14 August 2024, considered the Mpox outbreak as an extraordinary event that constitutes a public health risk to other States through the international spread of disease. Such an event requires a coordinated international response. The Committee advised that the current outbreak of mpox meets the criteria of a public health emergency of international concern (PHEIC).
Accordingly, mpox outbreak in DR Congo and some other countries in Africa was declared a public health emergency of international concern (PHEIC) on 14 August 2024. The report of the first meeting of Mpox IHR Emergency Committee 2024 has since been released by WHO.
Treatment of Mpox
Because monkeypox virus (MPXV) is closely related to smallpox, the therapeutics for smallpox is likely to be useful in treating mpox cases. Therefore, the antiviral drug tecovirimat (or TPOXX) that was originally developed and approved to treat smallpox has been authorized in Europe and the United Kingdom for the treatment of mpox. European Medicines Agency approved tecovirimat for treatment of mpox in January 2022 under exceptional circumstances.
Evidences in the context of mpox is very limited hence use of tecovirimat is accompanied with enrolment in a clinical trial. In the USA, it is currently available for mpox treatment as part of a clinical trial.
Tecovirimat’s safety and efficacy as an mpox treatment is yet to be established.
Clinical Trial of Tecovirimat (TPOXX) for Mpox Treatment
A randomized, placebo-controlled trial was launched in October 2022 to evaluate safety and effectiveness of the antiviral drug tecovirimat in individuals with monkeypox in the DR Congo which is a mpox-endemic country. 597 confirmed cases of mpox were enrolled and were randomly treated with tecovirimat or placebo in a hospital and were monitored for resolution of mpox symptoms.
The initial result of the study suggests that the antiviral drug tecovirimat was safe for the participants of the study. It did not cause any significant adverse effects. However, it was not effective in reducing the duration of mpox lesions with clade I mpox. Nevertheless, mortality among the participants was lower than overall mpox mortality in the DRC. Mortality reduced and lesions resolved faster for the participants of the trial regardless of whether they received tecovirimat or placebo. This suggested better health outcome when hospitalised and provided necessary care.
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References:
- WHO News release – First meeting of the International Health Regulations (2005) Emergency Committee regarding the upsurge of mpox 2024. Posted 19 August 2024. Available at https://www.who.int/news/item/19-08-2024-first-meeting-of-the-international-health-regulations-(2005)-emergency-committee-regarding-the-upsurge-of-mpox-2024
- WHO. News release – Mpox Q&A. Posted 17 August 2024. Available at https://www.who.int/news-room/questions-and-answers/item/mpox
- CDC. Tecovirimat (TPOXX) for Treatment of Mpox. Available at https://www.cdc.gov/poxvirus/mpox/clinicians/tecovirimat-ea-ind.html
- NIH 2024. News release – The antiviral tecovirimat is safe but did not improve clade I mpox resolution in Democratic Republic of the Congo. Posted on 15 August 2024. Available at https://www.nih.gov/news-events/news-releases/antiviral-tecovirimat-safe-did-not-improve-clade-i-mpox-resolution-democratic-republic-congo
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Related articles:
Monkeypox (Mpox) Outbreak Declared A Public Health Emergency of International Concern (14 August 2024)
Monkeypox (Mpox) Vaccines: WHO initiates EUL procedure (10 August 2024)
Virulent Strain of Monkeypox (MPXV) Spread Through Sexual Contact (20 April 2024)
Monkeypox virus (MPXV) variants given new names (12 August 2022)
Will Monkeypox go Corona way? (23 June 2022)
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