LONDON — The UK nurse who contracted Ebola while working in Sierra Leone likely caught the virus because she was using a visor instead of goggles while treating patients.

See also: Diary of UK nurse with Ebola reveals devastating suffering in Sierra Leone

Pauline Cafferkey, the first person diagnosed with Ebola on British soil, contracted the virus in December after returning from Sierra Leone, where she had been working for Save the Children.

In a report released Wednesday, Save the Children said when Cafferkey was re-deployed from Lakka to Kerry Town, she was unable to use the standard protective goggles there because she couldn't get them to fit her properly.

"She acquired a visor that was the same as the one which she had used in her initial training, and similar to the one she had worn at Lakka, but that was not used by Save the Children. Both visors and goggles are equally safe but there are slight differences in the types of clothing worn with each, and in the protocols for putting the equipment on and taking it off,"

Cafferkey, who was for a time in a critical condition in a London hospital, has since made a full recovery.

“We will never be 100% sure how Pauline contracted Ebola, but the independent panel found that it is most likely, though not conclusive, she acquired her illness while working at the Ebola Treatment Centre at Kerry Town in Sierra Leone," said Justin Forsyth CEO of Save the Children.

The NGO said that while visors and goggles are recommended by the World Health Organisation and used by the UK Ministry of Defence, there are differences in the protocols for each. It added that lessons had been learned.

“The panel found that where STC approved protocols may not have been followed, or where prescribed equipment was not used, they weren’t picked up immediately and therefore action might not have been taken quickly to correct them," the report says.

A child, center, stands underneath a signboard in Sierra Leone, Oct. 22, 2014. Image: Michael Duff/Associated Press

Save the Children says it has now tightened its protocols and procedures.

In recent weeks the three most affected countries — Guinea, Sierra Leone and Liberia — appear to be making strides against the Ebola epidemic first identified last March, according to the Associated Press.

The U.N. health agency said last week that, for the first time since June, the countries had reported fewer than 100 cases in the past week. Nearly 9,000 people have died from the virus spread through contact with bodily fluids.