A recent outbreak of Ebola virus in the Democratic Republic of Congo (DRC) was declared to be over on July 24 by the World Health Organization (WHO) — but then a new outbreak started on Aug. 1 in the country’s Kivu province. Vaccine research in several countries soldiers on amid the newest occurrence of the virus.

Rapid action by healthcare professionals and the deployment of experimental treatments and technologies helped to contain the previous outbreak from May and June, which claimed 28 lives. As the new outbreak unfortunately begins, scientists in Spain and the United States continue to develop their own vaccines.

The National Institute of Allergy and Infectious Diseases (NIAID) has discovered a promising set of antibodies in the blood of Ebola survivors that may provide protection against Zaire, Bundibugyo, and Sudan ebolavirus, preventing the virus from interacting with host cells in the human body.

Spanish researchers have produced their own viral antibodies, currently only effective against the most virulent Zaire strain; they hope to proceed with experimentation on mice within the next year and develop a vaccine that will tackle all five strains of the disease, Agence France-Press reports.

These efforts aim to improve upon the efficacy of the Merck prototype vaccine, which is now being administered in the most recent Ebola outbreak. However, this experimental vaccine is not without its flaws.

It provides protection only against the Zaire strain of ebolavirus, and its instability means that it is logistically difficult to transport to isolated communities. Surveillance of the vaccine’s effects and follow-up with vaccinated individuals is also a difficult task, according to Scientific American. Poor infrastructure and communication in the DRC and other remote, Ebola-prone areas mean that patients often fall off the radar, and could potentially reignite the chain of infection.

The success of the May and June DRC containment effort helped to keep that outbreak localized, unlike the West African outbreak of 2014, which sparked global panic and racked up over 28,000 cases.

The WHO acted quickly, sharing authority with the local health ministry, and deployed new, experimental tools to the area, including diagnostic tests, the Merck vaccine, and other experimental Ebola drugs, in order to facilitate the needs of physicians and boost survival rates. It will likely do the same with the newest outbreak.

Unfortunately, poor local health systems, lack of communication, and high mortality rates for Ebola patients remain a problem in containment efforts.

In many ways, sheer luck prevented the previous outbreak from spreading beyond its hot spots in the DRC: cases were reported near major trade routes and in communities separated by large distances.

With the new outbreak, the DRC might not be as lucky: Peter Salama, the WHO’s deputy director-general of emergency preparedness, told Science magazine that he is "more concerned" this time around since the virus has reached a conflict zone and a city already.