Background Survivors from Ebola virus disease (EVD) may be at the origin of EVD resurgence. Methods Simultaneous reactivity to at least 2 Ebola virus or Zaire ebolavirus (EBOV) antigens was detected in 11 of 488 (2.3%; 95% confidence interval [CI], 1.1–4.0) suspected EVD patients who were discharged as negative after 2 consecutive negative tests during the 10th Ebola outbreak in the Democratic Republic of the Congo. Results After extrapolating the total number of individuals discharged as negative during the entire outbreak, we estimated a total of 1314 additional missed Ebola cases. Conclusions These findings emphasize the usefulness of an EBOV serology analysis and the importance of extending epidemic surveillance to clinically suspected cases who were discharged as negative.