Experts from the World Health Organization provided an update on Sunday about the Disease X outbreak occurring in the Democratic Republic of the Congo. Although the report presents a more detailed picture of the outbreak, experts reiterated that the cause remains unknown. The report concludes that the current risk level in the affected region of the DRC is high. At a national level, the risk within the DRC is considered moderate and the regional and global risk levels currently are low. These estimates could change as more becomes known about the cause and spread of the disease.
The new WHO report lists 406 cases of this disease and 31 deaths. The first case was identified on October 24. The number of new cases reported per week apparently peaked in early November. Thus far, all the cases have occurred in the Kwango Province of the DRC. The most common symptoms include fever and cough.
The 406 cases and 31 deaths indicate a case fatality ratio of 7.6%. In contrast, the CFR of Covid-19 has been estimated to be about 1%, whereas the CFR of the 2002-2004 SARS outbreak was approximately 10%. Seasonal influenza typically has a case fatality ratio well below 1%.
The number of deaths reported by the WHO differs from previous estimates. Initial reports listed anywhere from 79 to 143 deaths. Most likely, the varied numbers reflect the stringency employed by the WHO to classify cases. They note that several deaths occurred outside of traditional healthcare facilities and still need to be investigated. In other words, the number of deaths reported by the WHO almost certainly will increase.
The WHO report further confirms previous information that the disease predominantly afflicts younger people. Over 64% of all cases have been reported in people under the age of 14. Approximately 53% of all cases have occurred in children under five years of age. Most deaths also have occurred in children; half of all deaths have occurred in children under the age of five. In contrast, most deaths attributed to Covid-19 occurred in older people.
The true severity of this disease is difficult to assess at this time. The WHO report notes that most patients also exhibited signs of extreme malnutrition. Additionally, malaria is common in this region. These and other factors could exacerbate the severity of this disease, resulting in more severe clinical presentations and an elevated death rate. The report also notes that limited medical information about the patients, like vaccine histories, is available. This lack of background information also complicates the investigation.
The cause of Disease X remains unknown. The symptoms certainly are consistent with a respiratory virus. The WHO report mentions that some groups of cases appear to have occurred within families. Spread among close family members also is consistent with a respiratory virus. But other possibilities, including a non-communicable etiology, cannot be ruled out. Samples obtained from patients are being analyzed by scientists. The results of these tests should provide more definitive information soon. Until then, healthcare workers and public health experts will continue to monitor the situation.
