Health authorities in the Democratic Republic of the Congo (DRC) have said they plan to introduce a second Ebola vaccine to tackle the second-worst outbreak of the virus in history.

The team overseeing DRC’s response announced the move on Saturday but did not say when the vaccine – manufactured by the US-based firm Johnson & Johnson – would be introduced.

It will complement another vaccine produced by US pharmaceutical giant Merck which has been administered to more than 220,000 people since the DRC’s Ebola epidemic erupted in the country’s eastern North Kivu and Ituri provinces in August 2018.

The Johnson & Johnson product has been a source of controversy among DRC health officials.

Former health minister Oly Ilunga Kalenga, who was stripped of oversight of the Ebola response in July, opposed its use, saying it had not been proven effective and could confuse local populations.

The Johnson & Johnson vaccine requires two injections eight weeks apart, unlike the Merck vaccine, which requires a single shot. The Merck product is experimental but is estimated to be 97.5 percent effective and , according to the World Health Organization (WHO), may protect a person for up to 12 months.

In their statement, the current Ebola response team said the Johnson & Johnson product was also safe for deployment and noted that it was already being trialled in neighboring Uganda and in the West African country of Guinea.

“It is a vaccine that other countries already use. Why can’t we use it in Congo to protect our population?” the statement said.

The statement added that health officials intended to start by offering the Johnson & Johnson vaccine to DRC traders who cross into Rwanda and then to residents of the province neighbouring the epicentre of the outbreak “to create a corridor of immunised people”.