Uganda is undertaking its largest ever anti-Ebola vaccination drive.

The decision to roll out the preventative vaccination program was announced Monday, following the deaths of three family members who visited neighboring Democratic Republic of Congo (DRC) in June.

Uganda shares a border with the DRC, which has been grappling with an Ebola outbreak for just over a year, and the disease recently crossed the border when an infected child and his family entered Uganda. So far, around 1,800 people in DRC have been killed by the virus.

The vaccine trial, scheduled to last two years, has already been rolled out in the Mbarara district in the southwest of the country, according to reports.

At estimated 800 people are expected to receive the vaccine including physicians, clinicians, nurses, and pharmacists. Cleaners, mortuary attendants, surveillance staff, ambulance workers, and burial teams — among those most likely to come into contact with the virus — will also receive vaccines.

“Developing effective vaccines and treatments against Ebola are ... global public health priorities. In this trial we hope to avail more information that will help us work towards having a licensed Ebola vaccine,” Pontiano Kaleebu, the project’s lead researcher, told Reuters.

A spokesperson from Uganda’s Medical Research Council (MRC), Pamela Nabukenya, said the trial is led by Ugandan researchers with the support of the London School of Hygiene and Tropical Medicine.

Though Uganda has had Ebola outbreaks in the past, the country has never an outbreak at the same scale as those in the DRC. The vaccine drive is part of an effort to prevent such an outbreak.

In 2000, Uganda experienced an outbreak with 425 reported cases and 224 deaths, followed by another in 2007, which saw 131 reported cases and 42 deaths. Since then, Ebola outbreaks in Uganda have been on a much smaller scale with, just one reported case and one death in 2011, and 17 cases and seven deaths in 2012.

The three people who passed away recently are the only known cases of Ebola in Uganda since the DRC's latest outbreak, the second worst in the country’s history, began last year.

Jane Ruth Aceng, Uganda’s health minister, said in June: “So even when we don’t have any Ebola cases in Uganda, even when we no longer have suspected cases, we shall still remain in response mode — because we’ve already had Ebola confirmed in the country and we cannot declare an end to the outbreak because there is a potential outbreak still on the other side [of the border].”