Tuesday, August 13, 2024

WHO Multi-country Outbreak of Mpox : External Situation Report #35

#18,238

Tomorrow the WHO will convene an IHR Emergency Committee meeting to discuss whether the increased spread of Mpox (formerly Monkeypox) clade I (see CDC Mpox Update & HAN #00513 On H-2-H Spread of Mpox From DRC To Neighboring Countries) in Africa represents a regional, or an international, public health emergency. 

Unlike the milder clade II Mpox virus which began its world tour in 2022, clade I (and newly emerged Ib) produce far more serious illness, and appear to be spreading more efficiently.  Children are disproportionately affected, at least in reporting from the DRC.

Hampering their evaluation, reporting on Mpox - just as we've seen with COVID - has declined significantly around the globe, despite constant pleas from the WHO.  Additionally, in some countries, the stigma of Mpox prevents some people from seeking treatment. 

As a result, the numbers we have on clade II infections around the world, and reports on the spread of clade I in and around the DRC, are probably significantly understated. A limitation this (and previous) WHO SitReps have repeatedly referenced. 

Complicating matters, there are 4 different clades of Mpox (Ia, Ib, II, IIb), each affecting different groups and producing different impacts.  The WHO's most recent assessment on each follows: 


Report Highlights
  • In June 2024 (latest complete monthly disease surveillance data available), a total of 934 new laboratory-confirmed cases of mpox and four deaths were reported to WHO from 26 countries, illustrating continuing transmission of mpox across the world. The most affected WHO regions, ordered by number of laboratory-confirmed cases, were the African Region (567 cases), the Region of the Americas (175 cases), the European Region (100 cases), the Western Pacific Region (81 cases) and the South-East Asia Region (11 cases). The Eastern Mediterranean region did not report cases in June 2024.
  • As reporting from countries to WHO has been declining, the current reported global data most likely underestimate the actual number of mpox cases.
  • Within the African Region, the Democratic Republic of the Congo reported most (96%) of the confirmed mpox cases in the reporting month. With limited access to testing in rural areas, 24% of clinically compatible (reported as suspected) cases in the country have been tested in 2024, with a positivity of around 65% at the national level. The confirmed case counts are, therefore, underestimates of the true burden.
  • This issue also features an update on the geographic expansion of mpox in the WHO African Region from July – August 2024, not yet captured in global surveillance data by 30 June 2024. Four new countries in Eastern Africa (Burundi, Kenya, Rwanda, and Uganda) reported their first mpox cases. All cases are linked to the expanding outbreak in East and Central Africa and all cases sequenced to date from these countries are clade I. Separately, Côte d’Ivoire is experiencing an outbreak of mpox linked to clade II MPXV and South Africa has reported two more confirmed cases.

The full 18-page PDF can be downloaded and viewed at this link. 

Like all viruses, Monkeypox continues to evolve, adapt, and diversify, and the longer the chains of human infection, the faster those changes are likely to occur (see Evolution of monkeypox virus from 2017 to 2022: In the light of point mutations).

Since the global eradication of smallpox in the 1970s, there is a general feeling that poxviruses - much like polio and the plague - are relics of the first half of the last century; something you only read about in history books. 

But smallpox vaccination was halted in the 1970s, and our collective immunity to poxviruses has diminished greatly. While the smallpox virus may be gone, its family (orthopoxvirus) tree contains dozens of branches, including Mpox viruses. 

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