On M-pox

While it isn't getting the attention it deserves, for the better part of a year we've been watching the rapid spread of a new, and arguably more dangerous, Mpox clade (Ib) which was first detected in the DRC in 2023 (see WHO Reports 1st Confirmed Cluster Of Sexually Transmitted MPXV Clade 1 in the DRC).

Meanwhile the milder clade IIb virus - which began its world tour in 2022 - continues to cause sporadic outbreaks around the globe (see WHO DON Mpox - South Africa). 

While that hasn't happened yet, the Mpox epidemic in the DRC continues to worsen, and neighboring nations are on heightened alert.  In recent weeks Mpox cases have been reported in Burundi, and given limited surveillance, other cases may be flying under the radar. 

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The caveat of course is that up until mid-May of 2022, the risk of Mpox Clade II spreading internationally was considered equally low.  The Mpox virus was only belatedly discovered to be spreading in multiple non-endemic nations, leading to the declaration of a PHEIC (Public Health Emergency of International Concern) the following July. 

As we've seen with COVID, H5N1, and other infectious disease reporting around the globe, surveillance and reporting on Mpox is often limited, or sometimes missing entirely.  The WHO described this situation in their last monthly Mpox update #34:

WHO continues to encourage all countries to ensure that mpox is a notifiable disease and to report mpox cases, including reporting when no cases have been detected (known as ‘zero-reporting’, as outlined in the Standing Recommendations on mpox issued by the WHO Director General).

This report does not highlight non-reporting countries. Therefore, it should be noted that an absence of reported cases from a country may be due to the country not reporting, rather than having no cases. Reporting to WHO has been declining, therefore, the decline in reported cases should be interpreted with caution.

A reminder that an absence of evidence is not necessarily evidence of absence.