WHO declares end to Ebola public health emergency

The World Health Organization (WHO) today announced the end of the Ebola public health emergency of international concern (PHEIC), noting that West Africa's outbreak nations have stamped out original transmission chains and have shown they can quickly extinguish occasional clusters as virus levels die out in survivors.

The WHO made the announcement after its Ebola emergency committee met today for the ninth time. After hearing updates from all three countries and responders, the panel noted that all three countries have passed observation and extended surveillance periods since the last case in the original transmission chains were reported.

As expected, new clusters continue to be reported, such as a recent one in Guinea, but they are becoming less frequent and the countries have quickly responded and limited the cases to no more than two generations of infection.

Committee members said the developments in West Africa are no longer an extraordinary event, that the risk of international spread is now low, and that the countries have the capacity to respond to new clusters. They said the situation no longer constitutes a PHEIC as defined by the International Health Regulations and added that the temporary recommendations made earlier be terminated.

WHO Director-General Margaret Chan, MD, MPH, accepted the emergency committee's recommendations.

Long-term viral persistence in semen

At a media briefing today, Chan said about 1,000 contacts have been identified in Guinea's latest flare-up, which was announced on Mar 17, and 142 of them considered high risk. Of 8 cases in Guinea's latest cluster, 5 are confirmed and 3 are probable. All are linked to the same transmission chain.

Though the WHO anticipates further clusters in the future—12 have been reported so far—they are becoming less frequent. Chan added that the outbreak countries have vaccines as a powerful containment tool. She also noted that enhanced lab capacity allows gene-sequencing data from individual patients to back up epidemiology investigations with much greater precision.

WHO officials said today that ongoing studies tracing virus persistence in males and females in Liberia and Sierra Leone show that virus levels can linger in the semen of male survivors—and with it the risk of sexual transmission—but they usually drop fairly rapidly.

In a few men, however, the virus has persisted as long as 15 months. WHO officials estimate that about 1% to 2% of male survivors are still shedding Ebola virus in their semen a year after recovery.

Donor help still needed

Bruce Aylward, MD, MPH, the WHO's executive director of outbreaks and health emergencies, said the end of the PHEIC won't change the WHO's involvement in the outbreak region over the next couple years. He said more than 1,000 people are still working in West Africa.

Aylward said sparks of Ebola activity, such as the one in Guinea, will now be classified as grade 2 crises, similar to, for example, Angola's current yellow fever outbreak.

According to a WHO statement, the committee emphasized the need for international donors to continue financial and technical support to help the countries prevent, detect, and rapidly respond to new Ebola outbreaks. The experts added that help is especially needed for expanding lab and vaccination capacity and to continue key Ebola research activities, such as exploring drugs that can help survivors clear persistent virus from the body.

The WHO still has two other active PHEICs, one for Zika virus complications and the other for polio.

See also:

Mar 29 WHO statement

Mar 29 WHO media briefing audio file

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