We have described the first ever comparative study conducted during an ongoing EVD epidemic to demonstrate the effectiveness of community-based confinement. The strategy was decisive in the control of the eastern DRC’s epidemic, which was arguably one of the most complex in the history of EVD since its discovery in 1976.
The 2018–2020 eastern DRC outbreak lasted two years despite the availability of experimental vaccine (29) and therapeutics (30) at the very beginning of the response. Public health performance indicators were poor, with increasing community deaths, poor CT (indicated by the high number of cases that had no known contacts), and delays between symptom onset and isolation (18)(29)(8). The change in strategy to adapt to a difficult context was necessary, and led to a rapid and drastic reduction in transmissibility which reduced incidence and helped bring the outbreak under control (2). The confinement strategy was then implemented to avoid a new spread of the epidemic, especially as the security situation was more critical.
Although implemented after the peak of the epidemic, this strategy played an important role in accelerating control as it contributed to rapidly stopping the remaining transmission chains. The overall comparison between intervention and control group showed a significant difference in the outcome indicators, namely the reproduction number, CFR, delay from symptom onset to case isolation, and vaccination rate amongst contacts. Moreover, for all confirmed cases from the intervention group, the delay between the date of vaccination and the onset of symptoms was less than ten days, meaning that all these cases were already infected and within the incubation period at the time they were vaccinated. This implies that, even if vaccinated, these contacts could have contaminated other people if they were not confined (vaccination is very effective when administered early to contacts (31). It is most effective in contacts of contacts, but community acceptance is still very important).
Survival analysis showed a higher survival of confirmed cases from the intervention group than the control group. The higher survival rate may be attributable to the early detection of confirmed cases in the intervention group, as supported by the shorter delay from symptom onset to case isolation in this group. This delay was reported as one of the factors associated with EVD death in Guinea during the 2013–2016 West Africa Ebola Epidemic (32). This survival difference is likely not treatment-related, as all hospitalized patients received almost within the same time frame, the same specific molecules that had already been validated in the first stage of a clinical trial conducted during the epidemic (30). Finally, the security context is unlikely to have had an impact as both groups were in the same localities and therefore subject to the same conditions.
The community containment strategy applied in eastern DRC from November 2019 to May 2020 is comparable to quarantine, but had crucial differences in the method of implementation, and the and the acceptance by those concerned. Firstly, it only involved contacts, as opposed to the general population (i.e., it was targeted). Secondly, it was designed by a multidisciplinary team including social scientists. The methodological approach based on community participation and engagement, inclusion of participants’ expectations, and the support of psychosocial experts at all levels mitigated the negative impact of confinement on mental health. No cases of mental disorders were reported among the confined population in contrast to what is reported in the confinements during COVID-19 (33). The implementation was also guided by WHO recommendations which state that if a decision to implement quarantine is taken, the authorities should ensure that those in quarantine are adequately supported. This means adequate food, water, protection, hygiene, and communication provisions; infection prevention and control (IPC) measures and monitoring of quarantined persons implemented (34). Introducing quarantine measures early in an outbreak may delay the introduction of the disease to a new country or area and may delay the peak where local transmission is ongoing. However, if not implemented properly, quarantine may also create additional sources of contamination and dissemination of the disease (17). In addition, quantitative models have also shown that quarantine and symptom monitoring of contacts with suspected exposure to an infectious disease are key interventions for the control of emerging epidemics (35).
The novel community confinement strategy that was applied during the 2018–2020 Kivu outbreak has great potential for future outbreaks. This is especially true because, while the availability of the EVD vaccine has massively reduced transmission during EVD outbreaks, there is a possibility of relapse up to five years after infection (36). This reinforces the need to consider, strengthen, and more broadly apply this community confinement strategy for the quick containment of future outbreaks. This will require trust from affected populations, which should not be taken for granted. However, the strategy itself can also serve to engender this trust, and therefore also strengthen the positive effect of other interventions requiring this trust which includes all five core pillars of EVD response (i.e., case management, case finding and contact tracing, infection prevention and control, safe and dignified burial, and risk communication and community engagement) (6).
As evidenced in the 2018–2020 Kivu Epidemic in eastern DRC, a single unaddressed EVD transmission chain can quickly escalate into further (and lethal) transmission. Therefore, CT strategies—including in areas with such weak health systems and conflict—should consider methods of rapid identification and isolation of contacts accompanied by a range of supportive interventions and with community engagement. This study has evidenced that doing so can lead to the rapid cessation of transmission, when done using the community confinement method. This does more than save lives through preventing onward transmission: it also has the added advantage of engaging affected individuals, as well as key and trusted community actors, which can help to engender and maintain trust in the response. This strategy can be adapted for a range of suitable infectious diseases and is inherently adaptable in the face of political or economic hurdles that might limit other interventions (including other and more costly forms of confinement like enforced quarantine or regional lockdowns). In short—for the ease of the strategy’s implementation, the integration of social sciences, the engagement of affected communities and trust built amongst them (which is itself key to the overall effectiveness of an outbreak response)—the community confinement strategy should be proactively considered as an effective, and efficient method of saving lives.