While warning that additional flare-ups are likely - setbacks we've already seen twice this year in Liberia - the World Health Organization has cautiously announced the end of 42 days in Liberia without a new Ebola case.
This is a milestone used to indicate the end of active chains of Ebola transmission - and with Guinea and Sierra Leone both beyond their 42 day watch periods - all of West Africa is now considered to be at zero transmission.
The caveat being that the Ebola virus undoubtedly still exists in the environment and we've ample evidence that some recovered Ebola patients can still carry, and shed, the Ebola virus for months despite being `cured'.
- In ECDC On Ebola Persistence & Rapid Risk Assessment, we looked at the unexpected relapse of Scottish nurse Pauline Cafferkey, nine months after her recovery from the the virus
- In WHO: Study Shows Ebola Virus Fragments May Be Detectable In Semen For > 9 Months, we saw additional evidence of the long-term presence of the Ebolavirus in male semen, and last May (see MMWR & WHO On Risks Of Sexual Transmission Of Ebola) we saw evidence of the sexual transmission of the virus.
All of which makes `staying at zero' a daunting task and far from assured. This from WHO.
Latest Ebola outbreak over in Liberia; West Africa is at zero, but new flare-ups are likely to occur
14 January 2016 | Liberia - Today, WHO declares the end of the most recent outbreak of Ebola virus disease in Liberia and says all known chains of transmission have been stopped in West Africa. But the Organization says the job is not over, more flare-ups are expected and that strong surveillance and response systems will be critical in the months to come.
Liberia was first declared free of Ebola transmission in May 2015, but the virus was re-introduced twice since then, with the latest flare-up in November. Today’s announcement comes 42 days (two 21-day incubation cycles of the virus) after the last confirmed patient in Liberia tested negative for the disease 2 times.
All 3 countries at zero“WHO commends Liberia’s government and people on their effective response to this recent re-emergence of Ebola,” says Dr Alex Gasasira, WHO Representative in Liberia. “The rapid cessation of the flare-up is a concrete demonstration of the government’s strengthened capacity to manage disease outbreaks. WHO will continue to support Liberia in its effort to prevent, detect and respond to suspected cases.”
This date marks the first time since the start of the epidemic 2 years ago that all 3 of the hardest-hit countries—Guinea, Liberia and Sierra Leone—have reported 0 cases for at least 42 days. Sierra Leone was declared free of Ebola transmission on 7 November 2015 and Guinea on 29 December.
“Detecting and breaking every chain of transmission has been a monumental achievement,” says Dr Margaret Chan, WHO Director-General. “So much was needed and so much was accomplished by national authorities, heroic health workers, civil society, local and international organizations and generous partners. But our work is not done and vigilance is necessary to prevent new outbreaks.”
Vigilence needs to be maintainedWHO cautions that the 3 countries remain at high risk of additional small outbreaks of Ebola, like the most recent one in Liberia. To date, 10 such flare-ups have been identified that were not part of the original outbreak, and are likely the result of the virus persisting in survivors even after recovery. Evidence shows that the virus disappears relatively quickly from survivors, but can remain in the semen of a small number of male survivors for as long as 1 year, and in rare instances, be transmitted to intimate partners.
“We are now at a critical period in the Ebola epidemic as we move from managing cases and patients to managing the residual risk of new infections,” says Dr Bruce Aylward, WHO’s Special Representative for the Ebola Response. “The risk of re-introduction of infection is diminishing as the virus gradually clears from the survivor population, but we still anticipate more flare-ups and must be prepared for them. A massive effort is underway to ensure robust prevention, surveillance and response capacity across all three countries by the end of March.”
WHO and partners are working with the Governments of Guinea, Liberia and Sierra Leone to help ensure that survivors have access to medical and psychosocial care and screening for persistent virus, as well as counselling and education to help them reintegrate into family and community life, reduce stigma and minimize the risk of Ebola virus transmission.
The Ebola epidemic claimed the lives of more than 11 300 people and infected over 28 500. The disease wrought devastation to families, communities and the health and economic systems of all 3 countries.