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Nigeria: 2019/2020 Yellow Fever

Source: https://www.who.int/csr/don/17-december-2019-yellow-fever-nigeria/en/
[h=1]Yellow fever – Nigeria[/h] Disease outbreak news: update
17 December 2019



Nigeria is responding to successive yellow fever outbreaks, with nearly a three-fold increase in number of confirmed cases in 2019 compared to 2018, suggesting intensification of yellow fever virus transmission. Additionally, there have been cases reported in parts of the country that have confirmed cases for the first time since the outbreak started in September 2017. From 1 January through 10 December 2019, a total of 4,189 suspected yellow fever cases were reported from 604 of 774 Local Government Area (LGAs) across all the 36 states and the Federal Capital Territory in Nigeria.

Of the total 3,547 samples taken, 207 tested positive for yellow fever by Immunoglobulin M (IgM) in Nigerian network laboratories. In addition, 197 samples from 19 states were confirmed positive using reverse transcriptase polymerase chain reaction (RT-PCR). The case fatality rate for all cases (including suspected, probable and confirmed) is 5.1%, and 12.2% for confirmed cases.

Sixty-eight per cent (134 cases) of the total (197 cases) confirmed cases were reported from four states, including Bauchi, Katsina, Edo and Ebonyi. Cases in Edo state have declined after a reactive vaccination campaign in late 2018. From 1 January through 10 December 2019, a total of 115 confirmed cases and 23 deaths were reported from Bauchi (62 cases), Katsina (38 cases) and Benue (15 cases). These cases tested positive by RT-PCR at national laboratories and/or RT-PCR and serologic tests at a regional reference laboratory, Institute Pasteur Dakar (IPD). Further epidemiological investigations are underway.

[h=3]Public health response[/h]
The outbreak response activities are being coordinated by a multi-agency yellow fever Incident Management System (IMS). On 5 November 2019, an Emergency Operations Centre (EOC) was activated for the third time, in response to the upsurge of confirmed yellow fever cases reported in a wide-geographic distribution including Bauchi, Benue and Katsina. A national rapid response team has been deployed to Bauchi and other affected states to support the outbreak response activities including surveillance, case management support and risk communications.

In addition to the existing laboratories in the country, new and operational laboratories have been added to the national laboratory network in Abuja, Edo and Enugu states.

A targeted response has been implemented in Alkaleri Local Government area (LGA) in Bauchi state. However, reports of ongoing transmission indicate that more vaccination and a wider geographical scope is needed. Katsina state has recently completed a state-wide preventive mass vaccination campaign; however, challenges linked to vaccine accountability and access to security-compromised areas may result in pockets of populations with immunity gaps. Risk of spread through population movements exist in neighbouring Kano and Kaduna states where population immunity is low.

Nigeria is considered a high-risk country by the Eliminate Yellow Fever Epidemics (EYE) strategy. By 2024, it is anticipated that all the states in Nigeria will have undergone campaign activities to protect at-risk populations against yellow fever. This plan may be further updated or accelerated based on risk, vaccine and implementation feasibility. The country is in the process of completing a planned phase-3 vaccination campaign in 2019 and evaluating the recently concluded mass vaccination campaign. [h=3]WHO risk assessment[/h]
The yellow fever outbreak transmissions reported in Bauchi, Benue and Katsina states since August 2019, with spread to multiple other states, represents an intensification of yellow fever transmission and an elevated risk for yellow fever outbreak to spread and amplify. This is particularly a high risk if yellow fever is introduced into densely populated urban areas where preventive mass vaccination campaigns have not been conducted so far. Areas at risk include those without prior reported cases since 2017 and areas with a large number of under-immunized populations including urban areas such as Kano and Lagos. The preventive mass vaccination campaigns for yellow fever and the ongoing effort to strengthen routine immunization are important activities to reduce the risk of disease spread and amplification.

WHO continues to monitor the epidemiological situation and review the risk assessment based on the latest available information. Based on available information, WHO currently assesses the overall risk as high at the national level, moderate at the regional level, and low at the global level.

Nigeria is facing several concurrent public health emergencies, including circulating vaccine-derived polio virus (cVDPV), measles, monkeypox, lassa fever, cholera outbreaks, and a humanitarian crisis in the north-east of the country. [h=3]WHO advice[/h]
Yellow fever is an acute viral haemorrhagic disease transmitted by infected mosquitoes and has the potential to spread rapidly, with serious public health impacts. There is no specific treatment, although the disease is preventable using a single dose of yellow fever vaccine, which provides lifetime immunity. Supportive care is required to treat dehydration, respiratory failure and fever; antibiotics are recommended to treat associated bacterial infections.

The early detection and investigation of yellow fever cases through strong surveillance is key to controlling the risk of yellow fever outbreaks. Prevention of mosquito bites (e.g. repellents, wearing long clothes) is an additional measure that limits the risk of yellow fever transmission. In urban centres, targeted vector control measures are also helpful to interrupt transmission.

WHO recommends vaccination against yellow fever for all international travelers more than nine months of age going to Nigeria, as there is evidence of persistent or periodic yellow fever virus transmission. Nigeria also requires a yellow fever vaccination certificate for travelers older than one year of age arriving from countries with risk of yellow fever transmission.

Yellow fever vaccines approved by WHO are safe, highly effective and provide life-long protection against infection. In the context of international travel, the amendment to Annex 7 of the International Health Regulations (IHR 2005) changes the period of validity of the related international certificate of vaccination against yellow fever, and the protection provided by vaccination against yellow fever infection from ten (10) years to the life of the person (traveler) vaccinated. Accordingly, as of 11 July 2016, for both existing or new certificates, revaccination or a booster dose of yellow fever vaccine cannot be required of international travelers as a condition of entry into a State Party, regardless of the date their international certificate of vaccination was initially issued.

On 1st July 2019, WHO updated the areas at-risk of yellow fever transmission and the corresponding recommendations for vaccination of international travelers. The list of countries at-risk, and revised recommendations for vaccination against yellow fever are available on the WHO website: International travel and health (ITH).

WHO encourages its Member States to take all actions necessary to keep travelers well informed of risks and of preventive measures, including vaccination. Travelers should also be made aware of yellow fever signs and symptoms and instructed to seek rapid medical advice should they develop signs of illness. Travelers returning to Nigeria who may be infected with possible high levels of the virus in the blood may pose a risk for the establishment of local cycles of yellow fever transmission in areas where the competent vector is present.

WHO does not recommend any restrictions on travel or trade to Nigeria on the basis of the information available on this outbreak.

For more information on yellow fever, please see:
 
Source: https://guardian.ng/news/yellow-fever-kills-three-in-plateau/

Yellow fever kills three in Plateau
By Isa Abdulsalami Ahovi, Jos
29 December 2019 | 3:32 am

The World Health Organisation (WHO) has confirmed 13 cases of Yellow Fever, which has resulted in three deaths in four local government areas of Plateau State.

WHO State Coordinator, Wonk Vingey Bassey, confirmed the incident while presenting a report on a survey conducted on affected councils during an emergency stakeholders’ meeting in Jos.

The meeting followed the outbreak of the disease in Jos North, Bassa, Riyom and Wase local government areas of the state.

Bassey, who gave the breakdown according to councils, said the deaths were recorded in Wase local government...
 
Source: https://guardian.ng/news/plateau-confirms-25-cases-of-yellow-fever/

Plateau confirms 25 cases of yellow fever
By Isa Abdulsalami Ahovi, Jos
19 January 2020 | 3:25 am

Of the 141 suspected yellow fever cases in Jos North, Wase, Bassa, Kanam and Riyom Local Governments of Plateau State, 25 cases have been confirmed.

Following the yellow fever outbreak, the rapid response team from the Nigeria Centre for Disease Control, Abuja and National Primary Healthcare Development Agency were dispatched to the state for analysis and investigation...
 
Source: https://www.vanguardngr.com/2020/11/strange-disease-delta-govt-unravels-cause-of-deaths/

STRANGE DISEASE: Delta govt unravels cause of deaths On November 6, 20205:06 pmIn
By Festus Ahon - Asaba

Delta State Government, Friday, said it has unravelled the cause of deaths of over 30 youths in Ute-Okpu, Ute-Erumu and Idumesa communities in Ika North East Local Government Area of the State, saying the deaths were caused by yellow fever.

The State Commissioner for Health, Dr Mordi Ononye who made the disclosure while briefing newsmen, said laboratory results of the samples collected pointed to the age-long disease.

Flanked by the Commissioner for Information, Mr Charles Aniagwu and the State Director General of Orientation Bureau, Mr Eugene Uzum, Ononye, however, explained that the results would further be authenticated at the Reference Region Laboratory in Dakar, Senegal where the samples have also be sent to.

Hear him: “Samples were collected from patients and sent to the laboratory. We have received results and the results point to yellow fever as the cause of deaths we heard of in those areas.

“The result we have received is helping to move us to a more definitive action, while we still wait for a final authentication from the Reference Regional Laboratory in Dakar”...
 
Dozens of people dead as Nigeria battles yellow fever, amid coronavirus

Authorities in Enugu said a strange ailment, now known to be yellow fever, had claimed over 50 lives in parts of the state since early September.


November 8, 2020

As Nigeria’s battle against the coronavirus intensifies with fears of a second wave, another deadly infectious disease is on the rise with dozens of fatalities already recorded.

The Nigerian Centre for Disease Control (NCDC) on Saturday confirmed that reported deaths from a “strange illness” in Enugu and Delta states in recent weeks were caused by yellow fever, an acute viral haemorrhagic disease that can kill within 10 days if symptoms become severe.
 
Source: https://dailypost.ng/2020/11/09/yellow-fever-claims-8-lives-in-bauchi/

Yellow fever claims 8 lives in Bauchi
Published on November 9, 2020
By Hafsat Abdulhamid

A yellow fever outbreak in Ganjuea Local Government Area of Bauchi State has claimed the lives of eight persons in the area.

This was revealed to journalists in Bauchi on Monday by the Executive Chairman of Bauchi State Primary Health Care Development Agency (BASPHCDA), Dr Rilwanu Mohammed.

Apart from the eight lives lost to the outbreak, Dr Mohammed informed that eight other positive cases in the area are currently being managed...
 
Source: https://www.premiumtimesng.com/news...deaths-from-yellow-fever-in-11-days-ncdc.html

Three states report 76 deaths from yellow fever in 11 days – NCDC
The NCDC said it is responding to the latest yellow fever outbreak.
byEbuka OnyejiandAgency Report
November 13, 2020

The Nigeria Centre for Disease Control (NCDC) says three states have recently reported a total of 76 deaths suspected to be from yellow fever.
Bauchi, Delta and Enugu states reported that the deaths occured between November 1 and 11, the Director General of NCDC, Chikwe Ihekweazu, told the News Agency of Nigeria.

PREMIUM TIMES reported the recent fatalities from ‘strange illnesses’ suspected to be yellow fever in these states.

On Friday, Mr Ihekweazu told NAN that the cases and deaths were reported to the agency by the state epidemiologists of the three affected states.

He disclosed that 74 suspected cases involving 35 deaths were reported from Delta State, 70 suspected cases with 33 deaths from Enugu, and 78 suspected cases with eight deaths from Bauchi State, respectively...
 
Source: https://punchng.com/breaking-yellow-fever-outbreak-spreads-to-three-enugu-lgas/

Yellow fever outbreak spreads to three Enugu LGAs
Published November 16, 2020
Raphael Ede, Enugu

There was palpable tension in Enugu State on Monday following the report of a suspected Yellow Fever outbreak in three more local government areas of the state.

Enugu State had been battling to contain the outbreak of the disease in two communities of Ette Uno and Umuopu in Igbo-Eze North Local Government Area of the state, which reportedly claimed 52 lives between late October when the outbreak was first reported and November 2020.

The state government has also confirmed it had received reports of strange deaths within communities in Nsukka, Isi-Uzo, and Igbo-Etiti LGAs.

A statement by the Commissioner of Health, Prof Ikechukwu Obi, released on Sunday night, disclosed that the ministry’s Rapid Response Team, LGA Rapid Response Teams in collaboration with International and National Partners had visited the communities to investigate the reports and had taken samples for testing...
 
Source: https://www.vanguardngr.com/2020/11...-yellow-fever-over-100m-unvaccinated-at-risk/

DEATHS FROM ‘STRANGE DISEASE’: 222 suspected cases of Yellow Fever, over 100m unvaccinated at risk
On November 22, 202010:08 am
By Chioma Obinna

Years after Nigeria reduced the prevalence of Yellow Fever, YF, the disease has ferociously returned and is spreading across the country.

Experts say that if not checked, the fever may spread across the 36 states of the country as Nigeria has a huge population of unvaccinated and unprotected people against the disease.

Nigeria, in past few weeks, has witnessed a re-emergence of YF following laboratory confirmation by the Nigeria Centre of Disease Control, NCDC, of what was initially tagged as “mysterious deaths from strange disease.”

Since then, the trend has continued unabated in more states like Benue apart from Delta and Enugu and Bauchi where it has been confirmed as YF.

According to the Director-General of NCDC, Dr. Chikwe Iheakweazu, as of November 13, 2020, a total of 222 suspected cases, 19 confirmed cases and 76 deaths have been reported in Bauchi, Delta and Enugu.

Most of the deaths occurred before laboratory samples were collected for testing....
 
Source: https://www.who.int/csr/don/24-november-2020-yellow-fever-nigeria/en/


Yellow fever – Nigeria


Disease outbreak news
24 November 2020



Reports of a cluster of deaths from an undiagnosed disease were notified on 1 November 2020 through Event Based Surveillance in two states, Delta and Enugu, located in southern Nigeria. The Delta State health surveillance system had been informed of the outbreak on 30 October 2020, following a cluster of deaths presenting with similar symptoms.
Figure 1. Epidemic curve of suspected cases for Delta and Bauchi states


figure1_20201124.PNG




Enlarge image



On 2 November 2020, the Nigeria Centre for Disease Control (NCDC) reported to WHO a cluster of deaths in Ute Okpu community in Ika North-East local government area (LGA) of Delta State. Additional cases were reported from 4 other wards of Ika North-East (Idumessah, Owa Alero, Owanta, and Umunede). A preliminary report for Delta State on 5 November 2020, notified of 48 suspected cases of yellow fever (YF) with 30 deaths (CFR 62.5%). The most frequent symptoms included 1-week history of fever, vomiting (with or without blood), bleeding, seizures, and unconsciousness. One patient was reported to have cough, sore throat, and hiccups. Of those 48 reported cases, the main occupation was farmers, and males were predominantly affected (75%). The YF vaccination status of most of the suspected cases is unknown. The index case developed symptoms on 24 July 2020 and died on 28 July 2020. Preliminary investigation did not reveal any significant travel history. Two blood samples were collected, along with nasal and throat swabs on 31 October 2020. Laboratory investigations were carried out at the mobile laboratory of Irrua Specialist Teaching Hospital (ISTH) in Delta State. All blood samples tested by polymerase chain reaction (PCR) were negative for Lassa fever and the throat swab was negative for severe acute respiratory syndrome coronavirus 2 . Six more blood samples were collected and sent to ISTH, Edo State and all were negative for Lassa fever, while three were positive for YF by PCR. As of 10 November 2020, 65 suspected cases, including 33 deaths, have been reported. Samples were collected from 27 cases and seven have tested positive for yellow fever by PCR.

On 4 November 2020, the Enugu State epidemiologist reported a cluster of deaths of unknown cause to NCDC. Investigations by the Rapid Response team for Enugu State on 4 November 2020 reported 10 deaths, with the majority being males aged 4 to 65 years old and with occupations as farmers. The most frequent symptoms included high grade fever, convulsion, and eventually coma, in addition to blood in the urine, mouth bleeding, bleeding in the respiratory tract, blood shot eyes and pain in the flank. The suggestive differential diagnosis was Lassa fever, YF, cerebrospinal meningitis and COVID-19. A total of 13 blood samples were collected and sent to the National Reference Laboratory in Abuja to be tested for viral haemorrhagic fevers. Results received on 10 November 2020 showed 6 PCR positive YF cases in Enugu State.

On 8 November 2020, Bauchi State reported 8 samples tested by PCR at the NCDC National Reference Laboratory positive for YF (7/8 from Ganjuwa LGA, 1/8 unknown LGA). Four of these samples were also IgM positive for YF. Detailed case investigations are ongoing, and the line list is currently being updated.

On 15 November 2020, 3 PCR positive samples for yellow fever were reported from Ogbadibo LGA in Benue State. These samples were also tested at the NCDC, National Reference Laboratory. Additionally, there has been a PCR positive sample for YF reported from Ohaukwu LGA in Ebonyi State. This LGA has also been the location of a cluster of probable YF cases that were IgM positive at national reference laboratory and had dates of onset July-August 2020. Security challenges in the LGA had hindered full investigation and work-up at the time of initial notification.

The outbreak encompasses 5 states in Nigeria: Delta, Enugu, Bauchi, and Benue and Ebonyi (Figure 2).
Figure 2. Geographic distribution of affected states and local government areas in Nigeria


figure2_20201124.PNG




Enlarge image



Nigeria is facing concurrent outbreaks of multiple pathogens. Delta State, located in the South-South geo-political zone of the country, is one of the Lassa fever affected states, though not considered one of the YF hot spot states. In 2020, 18 Lassa fever cases have been laboratory confirmed from 140 suspected cases, including 3 fatalities. Enugu state, in the South-East geopolitical zone of the country, shares boundaries with Benue (Ogbadibo LGA) where there are 3 confirmed cases of Lassa fever, and Ebonyi state which is one of the hotspot states for the Lassa fever outbreak. To date, 10 Lassa fever cases have been reported from Enugu state since the start of the year, including 2 fatalities (20% CFR). While Lassa fever cases are reported year-round, the peak period is December to April.

The relative proximity of Delta, Enugu, Benue and Ebonyi states with Lagos is an added concern, though population movements (and hence risk of spread) may have been reduced in the COVID-19 context. However, there is a lack of data on this, and the risk of spread should be monitored.

COVID-19 response efforts demand an extraordinary amount of time and resources from the country’s health system while lockdowns, travel restrictions and other mitigations to slow the spread have severely disrupted access to core essential health services. National and state authorities are currently focused on the COVID-19 pandemic, limiting the human resources required to conduct investigations and response activities for the YF outbreaks. Recent relaxation of COVID-19 measures will increase population mobility thereby increasing the risk for amplification of yellow fever, especially if introduced into urban centres. Population mobility in urban settings can be particularly challenging in conducting mass vaccination campaigns due to the size and diagnostic challenges of the operation (SAGE 2016). As of 23 November 2020, 66 383 COVID cases, including 1 167 deaths, have been reported in Nigeria.
Public health response


The current response at central level:
  • As of 7 November 2020, the National Emergency Operations Centre (EOC) for Yellow Fever was activated and led by NCDC, in close coordination with the State yellow fever EOC in the affected states
  • Coordination and deployment of technical support to affected states to ensure quality detailed investigations and response
  • Ensuring transport of positive samples to the regional reference laboratory, Institute Pasteur Dakar, for second stage confirmation
  • The designated national reference laboratories for testing (Central Public Health Laboratories and National Reference Laboratory) are currently testing samples using serology and PCR respectively
  • Reagents and consumables are available in all testing laboratories
  • Pictorial aids for YF case management has been updated and is being finalized
  • Development of an Incident Action Plan (IAP) for the response is ongoing
  • Case definitions for active case search have been developed and shared with the affected states
  • Daily monitoring and analysis of surveillance data from the affected states using the Surveillance Outbreak Response Management and Analysis System (SORMAS)
  • Engaging with Rapid Response Teams and State Epidemiologists for daily updates
  • Publishing press releases to update Nigerians on the YF situation in the country and provide information
  • Ongoing rumour monitoring across social and traditional media platforms
  • Dissemination of prevention messages across NCDC social media platforms
  • Two organised interviews on Channels TV Abuja & Wazobia FM Lagos
  • Conducting risk assessments in YF high risk states/ LGAs and ensuring active case searching in communities
  • Provision of national guidance to states on implementing quality vaccination response aligned to COVID-19 prevention standards for campaigns
  • The country is supporting entomological studies in Enugu, by the National Arbovirus Research Center (NAVRC)
The current response for Delta State:
  • An accelerated preventive yellow fever mass vaccination campaign ongoing in the affected LGA (Ika North-East LGA) Line listing of cases and active case searching in health facilities and communities
  • Risk communication activities and community engagement have been intensified in Ika North-East LGA on the risk of YF and steps to take to protect communities (e.g. vaccination, vector control)
  • Case management of suspected cases at a designated treatment centre (Federal Medical Centre, Asaba)
  • A state-wide YF preventive mass vaccination campaign is planned at the end of November 2020 that can be leveraged to accelerate the response
The current response for the cases in Enugu State:
  • An expanded emergency operation center for COVID-19 response to respond to the yellow fever outbreak on the risk of yellow fever and steps to take to protect communities (e.g. vaccination, vector control)
  • Community mobilization to all traditional rulers, town union presidents and other opinion leaders in Igbo-Eze North LGA
  • Intensified active search for suspected YF cases in the communities and health facilities
  • A case management center has been identified at the General Hospital Ogrute, Enugu-Ezike of Igbo-Eze North LGA)
  • Needs assessment for General Hospital Enugu – Ezike has been completed for designation as a treatment center in Enugu State
  • International Coordinating Group request is under preparation for a reactive vaccination campaign in the affected LGA
The current response for the cases in Bauchi State:
  • Detailed case investigation in process
  • Line listing of cases
  • Offsite support being given to response team pending the conclusion of the preliminary investigation
  • A state-wide YF preventive mass vaccination campaign planned in Bauchi in February 2021 can be leveraged and accelerated to support the response
The current response for the cases in Benue State:
  • Detailed case investigation in process
  • Line-listing being updated with 27 reported cases so far on the list
  • Offsite support being given to response team pending the conclusion of the preliminary investigation
  • As one of the high-risk states a preventive mass vaccination campaign is scheduled for 20 November 2020
Nigeria is considered a high-risk country by the Eliminate Yellow Fever Epidemics (EYE) strategy. Routine yellow fever vaccination was introduced to Nigeria’s Expanded Programme on Immunization (EPI) in 2004 with an estimated coverage of 54% (2019), with lower figures in some sub-groups. Population immunity against yellow fever in many areas around the country remains below herd immunity thresholds: the MICS 2016/2017 indicated that YF vaccination was 39% in children aged 12 to 23 months. To address the risk of outbreaks and increase population immunity, the EYE strategy PMVC component is being implemented in phases. There are over 30 million doses of YF vaccine in the country for PMVCs – with Delta and Bauchi among the states planned for the current phase of activities. Delta state was already scheduled for a PMVC in 2020. One LGA in Delta state and 4 LGAs in Bauchi state had a vaccination campaign in 2019. This YF vaccine supply and associated preparations could serve to meet the needs of outbreak response. The supplies also include resources such as PPE and hand sanitizers for COVID-19 prevention in a mass vaccination campaign. Enugu and Ebonyi are not included in the current planned PMVCs, however there is a possibility that vaccines and associated supplies in the country might help support an immediate response. By 2024, it is anticipated that all the states in Nigeria will have undergone campaign activities to protect at-risk populations against yellow fever. This plan may be further updated or accelerated based on risk, vaccine availability, and implementation feasibility.
WHO risk assessment


Nigeria is a high-risk country for yellow fever. The re-emergence of yellow fever in September 2017 in Nigeria has been marked by outbreaks over a wide geographical area. The yellow fever outbreaks reported in Bauchi, Benue and Katsina states from August to November 2019, with spread to multiple other states showed an expansion of YF transmission, and an elevated risk for YF outbreaks to rapidly spread and amplify, impacting areas without prior reported cases since 2017 and in areas with large under immunized populations. In the current year, suspected YF cases have been reported from all 36 states and the Federal Capital Territory (FCT) and confirmed YF cases across 9 states (Delta, Enugu, Bauchi, Benue, Kogi, Oyo, Edo Kwara and Katsina). These new outbreaks in Bauchi, Delta and Enugu are affecting areas without prior reported cases this year and suggest underlying sustained high viral transmission in the epizootic cycle with spillover to human populations. Due to: the risk of spread to other states with under-immunized populations, including to large urban centers; the high CFR; the potential for ongoing local transmission and amplification due to suboptimal vaccination coverage; and the occurrence of cases in peri-urban areas (e.g. in Delta State) and densely populated LGAs with proximity to Lagos, the risk is high.

There is no entomological information currently available for the affected LGAs, however previous entomological surveys conducted in 2018/2019 during outbreaks in settings of similar climate and vegetation in Ebonyi, Bauchi, Edo, Kogi and Kwara identified adult Aedes spp. mosquitos However, the region is entering the dry season (November to March) and vector densities are expected to be lower. The vector, Aedes aegypti is only moderately affected by drier conditions and remains active, and therefore sustained vector-borne transmission within human populations cannot be ruled out.

Nigeria is facing several concurrent public health emergencies, including circulating Vaccine Derived Polio Virus (cVDPV), measles, monkeypox, Lassa fever and cholera outbreaks as well as humanitarian crisis in the northeast of the country. WHO continues to monitor the epidemiological situation and review the risk assessment based on the latest available information. At present, the Yellow Fever outbreaks are considered high risk at national level, low at regional and global levels.
WHO advice


Yellow fever is an acute viral haemorrhagic disease transmitted by infected mosquitoes and has the potential to spread rapidly and cause serious public health impact. There is no specific treatment, although the disease is preventable using a single dose of yellow fever vaccine, which provides immunity for life. Supportive care to treat dehydration, respiratory failure and fever and antibiotic treatment for associated bacterial infections can reduce mortality and is recommended.

Yellow fever is endemic in Nigeria, a priority country for the EYE strategy. Accelerated phased YF PMVCs are planned to cover the entire country by 2024. Vaccination is the primary intervention for prevention and control of yellow fever. In urban centres, targeted vector control measures are also helpful to interrupt transmission. WHO and partners will continue to support local authorities to implement these interventions to control the current outbreak.

WHO recommends vaccination against yellow fever for all international travellers from 9 months of age going to Nigeria. Nigeria requires a yellow fever vaccination certificate for all travellers aged 9 months or over as a condition of entry.

Yellow fever vaccines recommended by WHO are safe, highly effective and provide life-long protection against infection. In accordance with the IHR (2005), the validity of the international certificate of vaccination against yellow fever extends to the life of the person vaccinated with a WHO approved vaccine. A booster dose of approved yellow fever vaccine cannot be required of international travellers as a condition of entry.

WHO encourages Member States to take all actions necessary to keep travellers well informed of risks and preventive measures, including vaccination. Travellers should also be made aware of yellow fever symptoms and signs and are instructed to seek rapid medical advice when presenting signs. Viraemic returning travellers may pose a risk for the establishment of local cycles of yellow fever transmission in areas where the competent vector is present.

The updated areas at-risk for yellow fever transmission and the related recommendations for vaccination of international travellers were updated by WHO on 1 July 2020 and are available on the WHO International Travel and Health website (see below).

WHO does not recommend any restrictions on travel or trade to Nigeria based on the information available on this outbreak.

For more information on yellow fever, please see:
 
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