CDC Warns DRC Ebola outbreak could exceed 20,000 cases without faster detection, isolation

Health officials have warned that the ongoing Ebola outbreak in the Democratic Republic of Congo (DRC) could grow to a scale similar to the deadliest epidemic in the disease's history, with new modelling suggesting the number of infections could eventually reach tens of thousands if containment efforts are unable to slow transmission.

Analysis released by the US Centres for Disease Control and Prevention (US CDC) has found that the outbreak could generate more than 20,000 cases under some scenarios, approaching the scale of the 2014-2016 West African Ebola epidemic, which recorded more than 28,000 infections and over 11,000 deaths.

The US CDC used computer models to examine how the outbreak might evolve under different conditions, including varying rates of case detection and isolation.

Researchers assessed factors such as the number of infections and deaths already reported, the likelihood that additional cases remain undetected and the speed with which infected people can be identified and separated from others.

“I want to be clear about what that means. A scenario is not a forecast. It is a planning tool. It answers the question: If this condition holds, or this intervention succeeds, or this variable changes, what does the trajectory look like?” said Jason Asher, Director of CDC's Centre for Forecasting and Outbreak Analytics (CFA).

“We model scenarios so that decision-makers can prepare for potential future outcomes, not so that we can predict which future will arrive.”

According to the analysis, stronger containment measures could significantly reduce the outbreak's eventual size.

Scenarios assuming that about half to 70 per cent of infected individuals are isolated before transmitting the virus projected totals closer to 10,000 cases, while lower isolation rates produced substantially higher estimates.

“If only 20 per cent of cases enter isolation within two days of symptom onset, more than 20,000 cases are projected in 2 out of 3 of our scenarios,” said Asher.

“If 70 per cent of cases started isolating within those two days, there is a 94 per cent probability of limiting the outbreak to fewer than 10,000 cases. This highlights the critical importance of rapid case identification and isolation.”

The warning comes amid a growing Ebola outbreak in the DRC that the Africa Centres for Disease Control and Prevention says has resulted in over 450 confirmed infections and 82 deaths.

Response efforts in parts of the country have been slowed by ongoing insecurity, with armed clashes forcing people from their homes and disrupting disease control work.

Misinformation and rumours about Ebola are also fuelling mistrust of health workers and discouraging some people from reporting symptoms or accepting isolation.