The WHO had directed all Ebola survivors and their sexual partners to receive counselling to guard against possible transmission of the disease.
This is contained in a statement made available by WHO to newsmen in Lagos on Saturday.
It indicated that the sexual transmission of the Ebola Virus had yet to be established.
WHO said, “The sexual transmission of the Ebola Virus from males to females is a strong possibility, but has not yet been proven; less probable, but theoretically possible.
“Studies have shown that Ebola virus can be isolated from semen up to 82 days after symptom onset.
“A recent case investigation identified genetic material (RNA) from the virus by nucleic acid amplification tests (such as RT-PCR) 199 days after symptom onset.
“This is well beyond the period of virus detecting ability in the blood of survivors and long after recovery from illness.
“The detection of virus genetic material many months after symptom onset is assumed to reflect the continuing, or at least very recent, presence of live and potentially transmissible Ebola virus.”
More surveillance data and research are needed on the risks of sexual transmission and particularly on the prevalence of viable and transmissible virus in semen over time, WHO said.
WHO recommends that, in the interim, all Ebola survivors and their sexual partners should receive counselling.
It added that this is to ensure safe sexual practices until their semen has twice tested negative; and survivors should be provided with condoms.
“Ebola survivors and their sexual partners should either abstain from all types of sex or observe safe sex through correct and consistent condom use until their semen has twice tested negative.
“Having tested negative, survivors can safely resume normal sexual practices without fear of Ebola virus transmission,” the statement added.