A recent study suggests that the end of smallpox vaccination in the Democratic Republic of Congo (DRC) is contributing to the country’s mpox surge, but it’s not the only cause. Researchers found that spillover events and increased transmissibility are also responsible for the spread of the virus.
According to Eugene Bangwen, a scientific fellow in outbreak research at the Institute of Tropical Medicine in Antwerp, waning smallpox immunity may be linked to the emergence of mpox in the DRC. “It’s quite strange that hotspots are emerging in parts of the country that are mainly savannahs and grasslands,” Bangwen said.
The study, which analyzed over 60,000 cases of mpox and 1,800 deaths reported by the DRC between 2010 and 2023, found a significant increase in suspected cases. The number of annual cases ranged from 2,302 to 14,636, with the highest incidence rates seen in children aged 5 years and younger.
The researchers suggest that some portion of the increase is linked to waning smallpox vaccination, which can protect against mpox. However, new spillover events and increased transmissibility are also likely contributing factors.
The World Health Organization (WHO) declared mpox a global public health emergency in August, citing the spread of clade I mpox in eastern DRC and other countries in Africa. The study’s findings support this declaration, highlighting the need for continued vigilance and response efforts to manage the outbreak.
Bangwen cautioned that while the situation is not as dire as it was during the 2022 global outbreak of clade IIb mpox, history may repeat itself if the virus is not properly managed. The study’s main takeaway is that there has been an exponential rise in mpox incidence in previously non-endemic health zones, which may be related to waning immunity and ecological factors.
Source: https://www.healio.com/news/infectious-disease/20241203/qa-waning-smallpox-immunity-not-the-only-cause-of-mpox-surge-in-drc