Uganda - Yellow Fever 2022 - 2023

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WEEKLY BULLETIN ON OUTBREAKS
AND OTHER EMERGENCIES

Week 13: 21 – 27 March 2022
Data as reported by: 17:00; 27 March 2022
...

Yellow fever Uganda

8 cases
0 Deaths
0.0% CFR

EVENT DESCRIPTION

On 6 March 2022, the Uganda Ministry of Health (MoH) reported
four yellow fever (YF) cases that tested YF Immunoglobulin M
(IgM) and YF plaque-reduction neutralization test (PRNT) positive
at the Uganda Virus Research Institute (UVRI).

These samples had been collected between 3 January and 18
February 2022. Three of these cases originated from Wakiso district
(Katabi, Masulita and Kitende subcounty) and one from Masaka
district (Bukakata subcounty). Three of the cases are females and
one is male. The ages of the cases range between 15 and 57 years.
As of 16 March 2022, a total of eight PRNT positive cases have
been reported, of which seven have been investigated and four have
a history of vaccination against YF. The affected districts in Uganda
are not located at the border. However, Masaka is located close to
the greater Kampala area and Wakiso encircles Kampala. Wakiso
also includes Entebbe, where the international airport is located.

PUBLIC HEALTH ACTIONS

The MoH has declared a yellow fever outbreak in the country.

The Public Health Emergency Operations Centre has been
activated.

National and district rapid response teams have been
deployed to initiate investigations in Wakiso and Masaka
districts.

Selected districts have been identified for phase 1 preventive
mass vaccination campaign.

A request has been submitted to the International

Coordinating Group on vaccine provision for preventive YF
vaccination in areas as indicated by ongoing investigations.

SITUATION INTERPRETATION

Uganda falls within the YF endemic zone in Africa and is classified
as a high-risk country in the “Eliminate Yellow Fever Epidemics”
(EYE) Strategy. The exact prevalence and incidence of yellow
fever in Uganda is not known. In addition, the country has
previously registered several YF outbreaks with the most recent
outbreaks reported in 2020 in Buliisa and Moyo districts, and
2019 in Masaka and Koboko districts. However, YF vaccine has
not yet been introduced into routine immunization and the MOH is
currently planning for a preventive campaign in selected districts.
Accordingly, these recurrent outbreaks illustrate the ongoing risk
of sylvatic spillover of YF and risk for disease amplification in both
rural and densely settled urban areas in the largely unimmunized
population.

PROPOSED ACTIONS

The government of Uganda should accelerate introduction
of YF vaccine in the routine Expanded Programme on
Immunization and complete preventive mass vaccination
activities to rapidly boost population immunity. Expedited
planning and implementation of these activities to protect the
population will help avert risk of future outbreaks.

All international travelers aged nine months and above
going to Uganda should be vaccinated against YF as there
is evidence of persistent or periodic YF virus transmission.
Local populations and travelers should avoid mosquito
bites including the use of repellents. The highest risk of
YF virus transmission is during the day and early evening.
Communities should be made aware of YF symptoms
and signs and instructed to rapidly seek medical advice if
presenting with signs and symptoms suggestive of this
infection.

View/Open

OEW13-2127032022.pdf (2.232Mb)

https://apps.who.int/iris/handle/10665/352663

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Source: https://www.who.int/emergencies/dise...em/2022-DON367


Yellow Fever – Uganda
25 April 2022

Outbreak at a glance
On 6 March 2022, WHO received notification from the Uganda Ministry of Health of four suspected yellow fever cases. As of 25 April 2022, a total of seven suspected cases tested positive for yellow fever antibodies by plaque reduction neutralization test. However, further investigations identified only one laboratory confirmed case of yellow fever reported from Wakiso district, Central Region. The MoH declared an outbreak, and a rapid response team was deployed to the affected districts. Due to the potential of epidemic spread in Uganda and the risk of spread to neighboring countries, WHO assesses the risk to be high at the national and regional levels.

Outbreak overview
On 6 March 2022, the Uganda Ministry of Health (MoH) notified WHO of four suspected yellow fever cases, with specimens collected between 2 January and 18 February 2022, which tested positive for yellow fever antibodies by enzyme-linked immunosorbent assay (ELISA) and by plaque reduction neutralization test (PRNT) at the Uganda Virus Research Institute (UVRI). As of 25 March 2022, three additional samples, with specimens collected between 1 – 13 October 2021, tested positive for antibodies by PRNT at the UVRI. All the seven suspected cases tested negative by Polymerase Chain Reaction.
Cases presented with symptoms including fever, vomiting, nausea, diarrhoea, intense fatigue, anorexia, abdominal pain, chest pain, muscle pain, headache, and sore throat. None of the cases presented with severe yellow fever symptoms of acute jaundice.
The majority of the suspected cases were females (n=6) with an age range between 15 to 57 years. Five were reported from Wakiso district, and one each from Masaka and Kasese districts.
Of the seven suspected cases, epidemiological investigations were conducted for six cases, and investigation is pending on one case. As of 25 April 2022, five of the six cases investigated had a recent history of vaccination and were consequently discarded in the absence of evidence suggesting vaccination failure, and one case (reported from Wakiso district) was confirmed as yellow fever.

Epidemiology of Yellow Fever
Yellow fever is an epidemic-prone mosquito-borne vaccine preventable disease caused by an arbovirus transmitted to humans by the bites of infected Aedes and Haemagogus mosquitoes. Once contracted, the yellow fever virus incubates in the body for 3 to 6 days. The majority of infections are asymptomatic, but when symptoms occur, the most common are fever, muscle pain with prominent backache, headache, loss of appetite, and nausea or vomiting. In most cases, symptoms disappear after 3 to 4 days.
A small proportion of patients, however, can have more severe symptoms of high-grade fever, abdominal pain with vomiting, jaundice and dark urine caused by acute liver and kidney failure. Death could occur within 7 - 10 days in about half of the patients with severe symptoms. There is currently no specific anti-viral drug for yellow fever, but early supportive treatment, such as specific care to treat dehydration, fever, and liver and kidney failure could improve survival rates.
Forty countries globally, 27 in Africa and 13 in Central and South America are classified as high-risk for yellow fever. Since September 2021, 13 countries in the WHO African Region have reported probable and confirmed yellow fever cases and outbreaks, including an ongoing outbreak under close investigation in neighbouring Kenya. These outbreaks are occurring in large geographic areas of the Western, Central and Eastern regions of Africa. They have affected areas that have previously conducted large-scale mass vaccination campaigns but with persistent and growing gaps in immunity due to lack of sustained population immunity through routine immunization and/or secondary to population movements (newcomers without history of vaccination). These reports indicate a resurgence and intensified transmission of the yellow fever virus.

Public health response

After the Uganda MoH declared a yellow fever outbreak in the country they activated the Public Health Emergency Operation center. They are also deploying a rapid response team to affected districts where all cases were reported to determine the extent of the outbreak, identify the at-risk population, conduct a risk assessment, initiate risk communication and community engagement activities and implement integrated vector control measures.
Yellow fever vaccine has not been introduced into the Uganda routine immunization schedule; however, the country has an imminent plan to introduce it in mid-2022, followed by phased mass vaccination campaigns (PMVCs). Pending the evolution of the situation and response planning, a request maybe submitted to the International Coordinating Group (ICG) on vaccine provision for preventive yellow fever vaccination in areas as indicated by ongoing investigations.

WHO risk assessment

Uganda is endemic for yellow fever and is classified as a high-risk country in the Eliminate Yellow Fever Epidemics (EYE) Strategy. The country has history of outbreaks reported in 2020 (Buliisa, Maracha and Moyo districts), 2019 (Masaka and Koboko districts), 2016 (Masaka, Rukungiri, and Kalangala districts) and in 2010 when ten districts were affected in Northern Uganda.
The confirmed case is reported from Wakiso district, close to the greater Kampala metropolitan area. The district also includes Entebbe, where the international airport is located.
Uganda has not introduced the yellow fever vaccine into routine immunization and the estimated overall population immunity is low (4.2%), and attributable to past reactive vaccination activities supported by ICG in focal districts including Yumbe, Moyo, Buliisa, Maracha, Koboko (2020), Masaka, and Koboko (2019), in limited scope in the Greater Kampala area (2017), Masaka, Rukungiri, and Kalangala districts (2016).
Epidemic spread of yellow fever is a risk in Uganda as there could be onward amplification if the virus is introduced in crowded urban areas that are known hubs for travel. There is the risk for further amplification and international spread because of frequent population movements (e.g., between Uganda, Democratic Republic of Congo and South Sudan), coupled with the low population immunity in some neighbouring countries.
The recurrent outbreaks indicate the ongoing risk of zoonotic spill over of yellow fever and risk for disease amplification in both rural and densely settled urban areas in the largely unimmunized population.
Despite the yellow fever vaccine being highly effective (99% effective within 30 days of vaccination), the risk of breakthrough cases exists. These cases should be investigated to identify and address possible causes of vaccine failure.
Considering the above-described scenario, the risk is assessed as high at the national and regional levels, and low at the global level.
WHO continues to monitor the epidemiological situation and review the risk assessment based on the latest available information.

WHO advice

Surveillance: WHO recommends close monitoring of the situation with active cross-border coordination and information sharing, due to the possibility of cases in neighbouring countries, the presence of a yellow fever outbreak in neighbouring Kenya, and the risk of onward spread. Enhanced surveillance with investigation and laboratory testing of suspect cases is also recommended.
Vaccination: Vaccination is the primary means for prevention and control of yellow fever. Completion of the nation-wide population protection through vaccination will help avert the risk of future outbreaks. WHO supports the plan of the Uganda Ministry of Health to introduce the yellow fever vaccine into the national routine immunization schedule, as well as the following implementation of phased mass vaccination campaigns.
Vector control: In urban centres, targeted vector control measures are also helpful to interrupt transmission. As a general precaution, WHO recommends avoidance of mosquito bites including the use of repellents and insecticide treated mosquito nets. The highest risk for transmission of yellow fever virus is during the day and early evening.
Risk communication: WHO encourages its Member States to take all actions necessary to keep travellers well informed of risks and preventive measures including vaccination. Travellers should be made aware of yellow fever symptoms and signs and instructed to rapidly seek medical advice if presenting signs and symptoms suggestive of yellow fever infection. Infected returning travellers may pose a risk for the establishment of local cycles of yellow fever transmission in areas where a competent vector is present.
International travel and trade: WHO advises against the application of any travel or trade restrictions on Uganda. Yellow fever vaccination is required by national authorities for international travellers over one year of age entering Uganda.
In accordance with the IHR (2005) third edition, the international certificate of vaccination against yellow fever becomes valid 10 days after vaccination and the validity extends throughout the life of the person vaccinated. A single dose of WHO approved yellow fever vaccine is sufficient to confer sustained immunity and life-long protection against yellow fever disease. A booster dose of the vaccine is not needed and is not required of international travellers as a condition of entry.

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WEEKLY BULLETIN ON OUTBREAKS
AND OTHER EMERGENCIES

Week 28: 4 - 10 July 2022
Data as reported by: 17:00; 10 July 2022
...

Yellow Fever Uganda

200 Suspected cases
0 Deaths

EVENT DESCRIPTION

There have been a total of 200 cases suspected to have yellow
fever in Uganda since the beginning of 2022 to 26 June 2022
with no deaths reported. However, only one case was confirmed
on 18 February 2022 by plaque reduction neutralization test
(PRNT) methods at the Uganda Virus Research Institute (UVRI).
The case is of an unvaccinated, 49-year-old female residing in
Wakiso district of the Central Region. The confirmed case has
since recovered from the disease.

In 2022, the 200 suspected cases have been reported from eight
districts in five regions of the country. A national rapid response
team was activated and deployed in March 2022 and subsequently
all affected districts have been supported with their response to
the disease including the activation of their respective district task
forces.

Among the total number of suspected cases, the majority (174,
87.0%) had an unknown vaccination status for yellow fever.
However, five suspected cases (2.5%) had been vaccinated and
21 (10.5%) were knowingly unvaccinated. A preventative mass
vaccination campaign (PMVC) for yellow fever has been planned
with implementation over the next two years which is expected
to begin in October 2022. The campaign targets the general
population of persons aged 9 months to 60 years and will be
carried out in phases through October 2024.

PUBLIC HEALTH ACTIONS

The national rapid response team and district rapid response
teams were activated to respond to the outbreak.

Health workers have been trained in case detection to
identify cases of yellow fever. A total of 159 workers have
been trained as of 26 June 2022, and 725 are expected to
be trained.

Risk communication activities were conducted via radio
spots and on television for community awareness and
sensitization for yellow fever prevention.

A PMVC campaign to vaccinate against yellow fever was
planned to occur in phases from October 2022 to October
2024.

Colleagues from UVRI conducted entomological surveillance
in Buikwe, Kasese, Masaka, and Wakiso districts to identify
the breeding sites for potential vectors, endophagic and
endophilic potential for yellow fever virus vectors, assess
the risk of future yellow fever outbreaks, and determine the
density of yellow fever vector sites. As of 26 June 2022, a
total of 34 578 adult mosquitoes have been collected and lab
investigation no them is ongoing.

Additional supplies for entomological assessment have been
procured.

SITUATION INTERPRETATION

The yellow fever outbreak in Uganda has calmed over the past few
weeks. So far only one case has been confirmed for the disease
by PRNT out of 200 total suspected cases since the beginning of
2022. Uganda has experienced challenges with case detection for
yellow fever in health centres personnel except for those working
in sentinel sites which is important for the continual surveillance
of the disease and to avoid resurgence of cases. Furthermore,
laboratory supplies for the confirmation of samples is limited
causing delays in status confirmation. Entomological surveillance
capacity is also being built which will aid in the prevention of
yellow fever and other vector-borne diseases.

https://apps.who.int/iris/bitstream/handle/10665/360358/OEW28-0410072022.pdf

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WEEKLY BULLETIN ON OUTBREAKS
AND OTHER EMERGENCIES

Week 5: 23 to 29 January 2023
Data as reported by: 17:00; 29 January 2023
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All events currently being monitored by WHO AFRO
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Uganda Yellow Fever Ungraded

Date notified to WCO 07-Mar-22
Start of reporting period 02-Jan-22
End of reporting period 25-Jan-23

Total cases 984
Cases Confirmed 2
Deaths 0
CFR 0

In 2022 and as of 13 January 2023, a total of 984 samples have been collected and tested for yellow fever (YF), of which 28 tested IgM+ for YF. Two cases were classified as laboratory-confirmed, including one in Masaka district and another one in Wakiso district. There are currently six cases under investigation, from five districts including Kasese (2), Buikwe (1), Buvuma (1), Masaka (1), and Wakiso (1).
...

https://apps.who.int/iris/bitstream/handle/10665/365810/OEW05-232901.pdf