| 18 Février 2016
SUMMARY
Human-to-human transmission directly linked to the 2014 Ebola virus disease (EVD) outbreak in West Africa was declared to have ended in Sierra Leone on 7 November 2015. The country then entered a 90-day period of enhanced surveillance to ensure the rapid detection of any further cases that might arise as a result of a missed transmission chain, reintroduction from an animal reservoir, importation from an area of active transmission, or re-emergence of virus that had persisted in a survivor. On 14 January, 68 days into the 90-day surveillance period, a new confirmed case of EVD was reported after a post-mortem swab collected from a deceased 22-year-old woman tested positive for Ebola virus. On 20 January, the aunt of the index case developed symptoms and tested positive for Ebola virus. The aunt was in a voluntary quarantine facility at the time she developed symptoms, after previously being identified as a high-risk contact. On 4 February the aunt of the index case provided a second consecutive Ebola-RNA-negative blood sample and was discharged. All contacts linked to the two cases had completed follow-up by 11 February 2016. Efforts to locate several untraced contacts in the district of Kambia will continue until at least 24 February. If no further cases are detected, transmission linked to this cluster of cases will be declared to have ended on 17 March.
Human-to-human transmission linked to the most recent cluster of cases in Liberia was declared to have ended on 14 January 2016. Guinea was declared free of Ebola transmission on 29 December 2015, and is approximately halfway through a 90-day period of enhanced surveillance that is due to end on 27 March 2016.
With guidance from WHO and other partners, ministries of health in Guinea, Liberia, and Sierra Leone have plans to deliver a package of essential services to safeguard the health of the estimated more than 10 000 survivors of EVD, and enable those individuals to take any necessary precautions to prevent infection of their close contacts. Over 300 male survivors in Liberia have accessed semen screening and counselling services. In addition, over 2600 survivors in Sierra Leone have accessed a general health assessment and eye exam.
To achieve the second key phase 3 response framework objective of managing residual Ebola risks, WHO has supported the implementation of enhanced surveillance systems in Guinea, Liberia, and Sierra Leone to enable health workers and members of the public to report any case of febrile illness or death that they suspect may be related to EVD. In the week to 14 February, 1251 alerts were reported in Guinea from all of the country’s 34 prefectures. The vast majority of alerts (1241) were reports of community deaths. Over the same period, 9 operational laboratories in Guinea tested a total of 316 new and repeat samples (18 samples from live patients and 298 from community deaths) from 17 of the country’s 34 prefectures. In Liberia, 877 alerts were reported from all of the country’s 15 counties, most of which (719) were related to live patients. The country’s 5 operational laboratories tested 924 new and repeat samples (789 from live patients and 135 from community deaths) for Ebola virus over the same period. In Sierra Leone 1872 alerts were reported from the country’s 14 districts. The majority of alerts (1500) were for community deaths. 978 new and repeat samples (37 from live patients and 941 from community deaths) were tested for Ebola virus by the country’s 7 operational laboratories over the same period.
The deployment of rapid-response teams following the detection of a new confirmed case continues to be a cornerstone of the national response strategy in Guinea, Liberia, and Sierra Leone. Each country has at least 1 national rapid-response team, with strengthening of national and subnational rapid-response capacity and validation of incident-response plans continuing throughout 2016.
Figure 1: Confirmed, probable, and suspected EVD cases worldwide
Table 1: Confirmed, probable, and suspected EVD cases inÂÂ Guinea, Liberia, and Sierra Leone
PHASE 3 RESPONSE FRAMEWORK
28 603 confirmed, probable, and suspected cases have been reported in Guinea, Liberia, and Sierra Leone, with 11 301 deaths (table 1; figure 1; figure 2) since the onset of the Ebola outbreak. The majority of these cases and deaths were reported between August and December 2014, after which case incidence began to decline as a result of the rapid scale-up of treatment, isolation, and safe burial capacity in the three countries. This rapid scale-up operation was known as phase 1 of the response, and was built on in the first half of 2015 during a period of continuous refinement to surveillance, contact tracing, and community engagement interventions. This period, termed phase 2, succeeded in driving case incidence to 5 cases or fewer per week by the end of July 2015. This marked fall in case incidence signalled a transition to a distinct third phase of the epidemic, characterised by limited transmission across small geographical areas, combined with a low probability of high consequence incidents of re-emergence of EVD from reservoirs of viral persistence. In order to effectively interrupt remaining transmission chains and manage the residual risks posed by viral persistence, WHO, as lead agency within the Interagency Collaboration on Ebola and in coordination with national and international partners, designed the phase 3 Ebola response framework. The phase 3 response framework builds on the foundations of phase 1 and phase 2 to incorporate new developments in Ebola control, from vaccines and rapid-response teams to counselling and welfare services for survivors. The indicators below detail progress made towards attaining the two primary objectives of the phase 3 framework.
PHASE 3 RESPONSE INDICATORS
Key performance indicators for the phase 3 response framework are shown for Guinea, Liberia, and Sierra Leone (table 2). A full list of phase 3 response indicators can be found in annex 2.
Human-to-human transmission linked to the most recent cluster of cases in Liberia was declared to have ended on 14 January 2016, 42 days after the 2 most-recent cases received a second consecutive negative test for Ebola virus. Human-to-human transmission linked to the primary outbreak in Guinea was declared to have ended on 29 December 2015, 42 days after the country’s most recent case, reported on 29 October (figure 5), received a second consecutive negative blood test for Ebola virus RNA. The country has now entered a 90-day period of enhanced surveillance, which is due to end on 27 March.
Human-to-human transmission directly linked to the 2014 Ebola virus disease outbreak in West Africa was declared to have ended in Sierra Leone on 7 November 2015. The country then entered a 90-day period of enhanced surveillance to ensure the rapid detection of any further cases that might arise as a result of a missed transmission chain, reintroduction from an animal reservoir, importation from an area of active transmission, or re-emergence of virus that had persisted in a survivor. On 14 January, 68 days into the 90-day surveillance period, a new confirmed case of EVD was reported in Sierra Leone after a post-mortem swab collected from a deceased 22-year-old woman tested positive for Ebola virus. The woman died on 12 January at her family home in the town of Magburaka, Tonkolili district, and received an unsafe burial. A number of contacts deemed to be at highest risk of developing EVD, including members of the close family of the index case, were transferred to voluntary quarantine facilities (VQFs) for the duration of their 21-day follow-up period. On 20 January, one of the contacts residing in a VQF in the district of Tonkolili developed symptoms and tested positive for Ebola virus. This second case in the cluster was the aunt of the index case, and cared for her niece during her illness. She was transferred to an Ebola treatment centre in Freetown, where she received treatment. On 4 February the aunt of the index case provided a second consecutive Ebola-RNA-negative blood sample and was discharged.
The 4 contacts who were residing in the same VQF as the second case in the cluster at the time she became ill remained under observation until 11 February, 21 days after their last possible exposure. All other contacts associated with the index case completed their 21-day follow-up period on 3 February. However, 48 contacts in the district of Kambia were not traced during the initial 21-day follow-up period, and efforts to locate them will continue for at least a further 21 days from 3 February. The search period will be extended by a further 21 days if any high-risk contacts remain unaccounted for by 24 February. Transmission linked to the cluster will be declared to have ended on 17 March if no further cases are reported.
With guidance from WHO and other partners, ministries of health in Guinea, Liberia, and Sierra Leone have plans in place to deliver a package of essential services to safeguard the health of the more than 10 000 individuals who have survived an Ebola infection. Not including individuals who have been tested as part of ongoing viral persistence studies, over 300 male survivors in Liberia have used semen screening and counselling services (table 2), enabling them to understand and, if appropriate, take precautions to protect their close contacts. In addition, over 2600 survivors in Sierra Leone have accessed a general health assessment and specialised eye exam (visual problems are commonly reported complications in individuals who have survived an Ebola infection).
To manage and respond to the consequences of residual Ebola risks, Guinea, Liberia, and Sierra Leone have each put surveillance systems in place to enable health workers and members of the public to report any case of febrile illness or death that they suspect may be related to EVD to the relevant authorities. In the week to 31 January, 1251 alerts were reported in Guinea from all of the country’s 34 prefectures. The vast majority of alerts (1241) were reports of community deaths. In Liberia, 877 alerts were reported from all of the country’s 15 counties, most of which (719) were related to live patients. In Sierra Leone 1872 alerts were reported from all of the country’s 14 districts. The majority of alerts (1500) were for community deaths.
As part of each country’s EVD surveillance strategy, blood samples or oral swabs should be collected from any live or deceased individuals who have or had clinical symptoms compatible with EVD. In the week to 14 February, 9 operational laboratories in Guinea tested a total of 316 new and repeat samples from 17 of the country’s 34 prefectures. The trend in the number of samples tested each week has remained flat for the past two months. 94% of all samples tested in Guinea were swabs collected from dead bodies. By contrast, 85% of the 924 new and repeat samples tested in Liberia over the same period were blood samples collected from live patients. In addition, all 15 counties in Liberia submitted samples for testing by the country’s 5 operational laboratories. 978 new and repeat samples were collected from all 14 districts in Sierra Leone and tested by 7 operational laboratories. 96% of samples in Sierra Leone were swabs collected from dead bodies (table 2; figures 3 and 4).
1241 deaths in the community were reported from Guinea in the week to 31 January through the country’s alert system (table 2). This equates to 55% of the 2248 community deaths expected based on estimates of the population and a crude mortality rate of 11 deaths per 1000 people per year. 158 deaths in the community were reported from Liberia over the same period, representing approximately 16% of the 982 community deaths expected per week. 1500 deaths in the community were reported from Sierra Leone, representing approximately 72% of the 2075 community deaths expected per week.
The deployment of rapid-response teams following the detection of a new confirmed case continues to be a cornerstone of the national response strategy in Guinea, Liberia, and Sierra Leone. Each country reports to have at least 1 national rapid-response team (table 2). Strengthening of national and subnational rapid-response capacity and validation of incident-response plans is continuing throughout 2016.
Table 2: Key performance indicators for phase 3ÂÂ inÂÂ Guinea, Liberia, and Sierra Leone in the 3 weeks to 14 February 2016
All data provided by WHO country offices. For definitions of key performance indicators see Annex 1. **Number of estimated survivors not yet confirmed by Liberia WHO country office. #Reported services accessed in Liberia currently include semen screening and counselling for male survivors; reported services accessed in Sierra Leone currently include a general health assessment and eye exam. *Data correspond to the three weeks ending 20 December 2015.
