The previous toll released on December 26 was 7,693 deaths and 19,695 cases.
Almost all the deaths and cases have been recorded in three west African countries worst-hit by the outbreak: Sierra Leone, Liberia and Guinea.
Those apart, six have died in Mali, one in the United States and eight in Nigeria, which was declared Ebola-free in October.
Spain and Senegal, which have both been declared free of Ebola, meanwhile counted one case each, but no deaths.
Sierra Leone, which has overtaken Liberia as the country with the most infections, counted 9,409 cases and 2,732 deaths on December 27, the WHO said yesterday.
On Christmas Eve, the death toll was 2,655 and there were 9,203 cases. Sierra Leone imposed a lockdown on Christmas and New Year festivities to curb the spread of the virus.
Liberia, long the hardest-hit country, has seen a clear decrease in transmission over the past month.
As of December 27, the country counted 7,977 cases and 3,413 deaths, up from 7,862 cases and 3,376 deaths recorded in the previous update.
In Guinea, where the outbreak started a year ago, 2,695 Ebola cases and 1,657 deaths were recorded up to December 27. The previous tally was 2,630 Ebola cases and 1,654 deaths as of December 24.
Ebola, one of the deadliest viruses known to man, is spread only through direct contact with the bodily fluids of an infected person showing symptoms such as fever or vomiting.
People caring for the sick or handling the bodies of people infected Ebola are especially exposed.
As of December 21, a total of 666 healthcare workers were known to have contracted the virus, and 366 of them had died, according to WHO.