In an effort to stop the spread of a recent Ebola outbreak that has killed four people in the Democratic Republic of the Congo’s northeastern region, the country’s health ministry has approved the use of a new WHO-backed vaccine, a spokesman told Reuters on Monday.

The vaccine, rVSV-ZEBOV, developed by pharmaceutical giant Merck showed a 100% protection rate during trials conducted in Guinea last December. Of nearly 6,000 people who received the vaccine, all were confirmed virus-free 10 days later.

The vaccine won’t be available for mass use until 2018, according to the WHO.

But in the event of an Ebola outbreak, Merck manufactured 300,000 doses of the vaccine with the $5 million provided by GAVI, the global vaccine alliance.

And now, the DRC has stepped up to the plate, approving the use of the new experimental vaccine to counter the outbreak.

A total of 52 suspected cases have been registered in the country since May 12, including two confirmed cases, the country’s WHO spokesman, Eugene Kabambi told Reuters.

The situation appeared to be under control, Kabambi added, and details about the vaccination campaign will be announced after the health ministry meets with its partners.

Should a confirmed case be identified outside those currently being monitored, the vaccination will be deployed, another spokesman from the UN’s health agency, Tarik Jasarevic, further explained.

Only then would it be offered "to contacts and contacts of contacts of a confirmed EVD case, including health care workers and field laboratory workers," Jasarevic said.

Officials claim that up to 400 people are suspected to have had contact with individuals carrying the virus and are now being monitored.

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The outbreak in 2014 across West Africa made headlines, killing over 11,000 people.

At the time, health services were unprepared and the WHO has even admitted that their response was “too slow.”

This time around, health services are better prepared. However, transporting and storing the vaccines in special containers could be made difficult by the location of the infection, in Congo’s isolated northeastern forests.

According to the WHO the world is currently not prepared to properly respond to two outbreaks, let alone the next big pandemic. It will come down to each of us to call on world leaders to continue to invest in vaccination and emergency preparedness.