The World Health Organization has updated numbers of Mpox cases and revised vaccine recommendations, revealing that nearly two years after the global outbreak began, cases may be significantly underestimated.
From 2022 through March 2024, more than 95,200 people have developed mpox infections and 185 patients have died across 117 countries, according to the WHO’s 32nd situation report, with just 10 countries account for 81% of reported cases, with the US, Brazil, and Spain making the top three.
Cases have risen in Africa in recent months, especially in the Democratic Republic of Congo, as well as the UK, Puerto Rico, and Vietnam.
However, most other countries have reported low levels of transmission – a total of 466 new cases were reported in March, which represents a 37% decline over the number of new cases reported during the previous month.
WHO spokesperson Emily Harris said that while the drop may seem to reflect success, the organisation acknowledged that as surveillance had been declining, the actual number of cases was likely to be much higher worldwide.
“All regions reported a reduction in case counts in March 2024 compared to the previous month except the Western Pacific Region (n = 32 vs 25). But as this apparent decrease occurred in the context of declining reporting it should, therefore, be interpreted with caution,” Ms Harris said.
“About 96% of those affected by the virus have been males, and most cases have been transmitted during sexual encounters and the organisation is urging countries to consider pre-exposure vaccines for adults and children in areas with documented risks and for those with multiple sexual contacts.
“Health care workers who might have repeated exposures and contacts of people with mpox could also be vaccinated, WHO noted, although postexposure vaccination seems to be less effective.”
Other key epidemiological findings from the report include:
- As of 31 March 2024, 96.4% (85,328 /88,513) of cases with available data are male, with a median age of 34 years (interquartile range: 29-41 years). The age and sex distribution of cases remains stable over time and most cases in the last months, especially outside the African Region, continue to be among adult men (18 – 44 years old).
- Among laboratory-confirmed cases with age data available, 1.3% are aged 0 -17 years, including 333 (0.4%) aged 0-4 years. The majority of confirmed Mpox cases aged 0-17 years were reported from the Region of the Americas. The overall proportion of cases under 18 years of age in the Region of the Americas is 1.2%, similar to the proportion observed globally.
- Of all reported modes of transmission outbreak in the global outbreak, sexual encounters are the most common (18 420 / 22 096; 83.4%) transmission event, followed by person-to-person non-sexual contact. This pattern has persisted over the last six months, with 95.7% (692 / 723) of new cases reporting sexual contact.
- Among cases where at least one symptom is reported (n = 35 997), the most common symptom is any rash (89.8% of cases), followed by fever (58.3%), and systemic rash or genital rash (54.7% and 49.6% respectively).
- Around half (18 335 / 35 316; 51.9%) of cases with available information in this outbreak are reported to be in persons living with HIV. This proportion is consistent for cases reported in the last six months (481 / 514; 51.7%) and is related to the common risk factor of sexual exposure between the two conditions.