Global & Disaster Medicine

Archive for the ‘Yellow Fever’ Category

U.S. trends in occurrence of nationally reportable vectorborne diseases during 2004–2016.

CDC-MMWR

Rosenberg R, Lindsey NP, Fischer M, et al. Vital Signs: Trends in Reported Vectorborne Disease Cases — United States and Territories, 2004–2016. MMWR Morb Mortal Wkly Rep. ePub: 1 May 2018. DOI: http://dx.doi.org/10.15585/mmwr.mm6717e1.

Key Points

•A total of 642,602 cases of 16 diseases caused by bacteria, viruses, or parasites transmitted through the bites of mosquitoes, ticks, or fleas were reported to CDC during 2004–2016. Indications are that cases were substantially underreported.

•Tickborne diseases more than doubled in 13 years and were 77% of all vectorborne disease reports. Lyme disease accounted for 82% of all tickborne cases, but spotted fever rickettsioses, babesiosis, and anaplasmosis/ehrlichiosis cases also increased.

•Tickborne disease cases predominated in the eastern continental United States and areas along the Pacific coast. Mosquitoborne dengue, chikungunya, and Zika viruses were almost exclusively transmitted in Puerto Rico, American Samoa, and the U.S. Virgin Islands, where they were periodically epidemic. West Nile virus, also occasionally epidemic, was widely distributed in the continental United States, where it is the major mosquitoborne disease.

•During 2004–2016, nine vectorborne human diseases were reported for the first time from the United States and U.S. territories. The discovery or introduction of novel vectorborne agents will be a continuing threat.

•Vectorborne diseases have been difficult to prevent and control. A Food and Drug Administration–-approved vaccine is available only for yellow fever virus. Many of the vectorborne diseases, including Lyme disease and West Nile virus, have animal reservoirs. Insecticide resistance is widespread and increasing.

•Preventing and responding to vectorborne disease outbreaks are high priorities for CDC and will require additional capacity at state and local levels for tracking, diagnosing, and reporting cases; controlling vectors; and preventing transmission.

The figure above is a map of the United States showing reported cases of tickborne disease in U.S. states and territories during 2004–2016.

Reported cases* of tickborne disease — U.S. states and territories, 2004–2016

 

The figure above is a map of the United States showing reported cases of mosquitoborne disease in U.S. states and territories during 2004–2016.

Reported cases* of mosquitoborne disease — U.S. states and territories, 2004–2016

 

The figure above is a bar chart showing reported nationally notifiable mosquitoborne, tickborne, and fleaborne disease cases in U.S. states and territories during 2004–2016.

Reported nationally notifiable mosquitoborne,* tickborne, and fleaborne disease cases — U.S. states and territories, 2004–2016


The number of reported cases of disease from mosquito, tick, and flea bites has more than tripled in the USA (2004-2016)

CDC

More cases in the US (2004-2016)

  • The number of reported cases of disease from mosquito, tick, and flea bites has more than tripled.
  • More than 640,000 cases of these diseases were reported from 2004 to 2016.
  • Disease cases from ticks have doubled.
  • Mosquito-borne disease epidemics happen more frequently.

More germs (2004-2016)

  • Chikungunya and Zika viruses caused outbreaks in the US for the first time.
  • Seven new tickborne germs can infect people in the US.

More people at risk

  • Commerce moves mosquitoes, ticks, and fleas around the world.
  • Infected travelers can introduce and spread germs across the world.
  • Mosquitoes and ticks move germs into new areas of the US, causing more people to be at risk.

The US is not fully prepared

  • Local and state health departments and vector control organizations face increasing demands to respond to these threats.
  • More than 80% of vector control organizations report needing improvement in 1 or more of 5 core competencies, such as testing for pesticide resistance.
  • More proven and publicly accepted mosquito and tick control methods are needed to prevent and control these diseases.

Vector-Borne Diseases Reported by States to CDC

Photo of mosquito

Mosquito-borne diseases

  • California serogroup viruses
  • Chikungunya virus
  • Dengue viruses
  • Eastern equine encephalitis virus
  • Malaria plasmodium
  • St. Louis encephalitis virus
  • West Nile virus
  • Yellow fever virus
  • Zika virus

 

Photo of Tick

Tickborne diseases

  • Anaplasmosis/ehrlichiosis
  • Babesiosis
  • Lyme disease
  • Powassan virus
  • Spotted fever rickettsiosis
  • Tularemia

 

Photo of Flea

Fleaborne disease

  • Plague

For more information: https://wwwn.cdc.gov/nndss/

Graphic: Disease cases from infected mosquitoes, ticks, and fleas have tripled in 13 years

Graphic: Disease cases from mosquitoes (2004-2016, reported)

Graphic: Disease cases from ticks (2004-2016, reported)


Nearly one billion people will be vaccinated against yellow fever in 27 high-risk African countries by 2026 with support from WHO, Gavi – the Vaccine Alliance, UNICEF and more than 50 health partners.

WHO

Nearly one billion people will be vaccinated against yellow fever in 27 high-risk African countries by 2026 with support from WHO, Gavi – the Vaccine Alliance, UNICEF and more than 50 health partners.

The commitment is part of the Eliminate Yellow fever Epidemics (EYE) in Africa strategy, which was launched by Dr Tedros Adhanom Ghebreyesus, WHO Director-General, Professor Isaac Folorunso Adewole, Nigeria’s Minister of Health and partners at a regional meeting in Abuja, Nigeria on Tuesday (10 April).

“The world is facing an increased risk of Yellow fever outbreaks and Africa is particularly vulnerable,” said Dr Tedros. “With one injection we can protect a person for life against this dangerous pathogen. This unprecedented commitment by countries will ensure that by 2026 Africa is free of Yellow fever epidemics.”

During the three-day EYE strategy regional launch meeting representatives from key African countries, WHO, UNICEF, Gavi, and other partners are developing a roadmap on how to roll-out the EYE strategy at national level. This implementation effort follows the endorsement of the strategy by African Ministers of Health at the 67th WHO regional committee in September 2017.

“This comprehensive, global strategy offers an unprecedented opportunity to end the devastating Yellow fever epidemics that periodically impact Africa,” said Dr Seth Berkley, CEO of Gavi, the Vaccine Alliance. “Ensuring that the most vulnerable communities have access to the vaccine through routine systems plays a central role in making this happen. Vaccine manufacturers and Gavi partners have worked hard to improve the global vaccine supply situation in recent years to make sure there is enough vaccine to respond to outbreaks, allow preventive campaigns and that routine immunization functions at full capacity.”

The three objectives of the strategy include protecting at-risk populations through preventive mass vaccination campaigns and routine immunization programmes, preventing international spread, and containing outbreaks rapidly. Developing strong surveillance with robust laboratory networks is key to these efforts.

UNICEF will make vaccines available, advocate for greater political commitment and provide support in vaccinating children through routine immunization as well as during outbreaks of the disease.

“Today, the threat of yellow fever looms larger than ever before, especially for thousands of children across Africa,” said Stefan Peterson, UNICEF’s Chief of Health. “Given that almost half of the people to be vaccinated are children under 15 years of age, this campaign is critical to saving children’s lives, and would go a long way toward stamping out this disease.”

After outbreaks of Yellow fever in densely populated cities in Angola and the Democratic Republic of Congo caused 400 deaths in 2016, the acute viral haemorrhagic disease re-emerged as a serious global public health threat. Brazil is currently battling its worst outbreak of Yellow fever in decades with more than 1,000 confirmed cases. The ease and speed of population movements, rapid urbanization and a resurgence of mosquitoes due to global warming have significantly increased the risk of urban outbreaks with international spread.

Experience in West Africa demonstrates that the EYE strategy can work. When Yellow fever re-emerged as a public health issue in the early 2000s, countries in the region controlled the epidemics through preventive mass campaigns combined with routine immunization. No yellow fever epidemics have been recorded since in countries which successfully implemented this approach.

Note to the Editors

The EYE strategy partners include GAVI the Vaccine Alliance, Endemic and New Technologies Franchise Sanofi Pasteur, Sealy Center for Vaccine Development at the University of Texas, GE Foundation, United Nations Children’s Fund (UNICEF), United States Agency for International Development (USAID), Agence de Médecine Préventive (AMP), School of Veterinary Medicine University of Surrey, Bio Manguinhos/Fiocruz, Department for International Development (DFID), Institut Pasteur Dakar, ExxonMobil, Save the Children, ArcelorMittal, Wellcome Trust, Imperial College London, Centers for Disease Control and Prevention (CDC), United Nations High Commissioner for Refugees (UNHCR), Sanofi Pasteur, Department of Tropical Medicine University of Hawaii, Medair, Chumakov Federal Scientific Center for Research & Development of Immune-and-Biological Products Russian Academy of Medical Sciences, China National Biotech Group, Skoll Global Threats Fund, Bill & Melinda Gates Foundation, International Federation of Red Cross and Red Crescent Societies (IFRC), National Institutes of Health (NIH), BioProtection Systems/NewLikn Genetics Corp., Robert Koch-Institut, Regional Immunization Technical Advisory Group (RITAG), PATH – Center for Vaccine Innovation and Access, Department of Entomology University of California, World Meteorological Organization (WMO), Vaccinology and Immunology Unit University Hospitals Geneva, Nigerian Academy of Science, Médecins Sans Frontières (MSF), Instituto Evandro Chagas (IEC), International Organization for Migration (IOM) and European Centre for Disease Prevention and Control (ECDC).

 


The Brazilian Ministry of Health yesterday noted 211 newly confirmed yellow fever cases, including 38 more deaths.

Brazil

O Brasil confirmou 1.131 casos e 338 óbitos no período de 1º julho de 2017 a 27 de março deste ano. No mesmo período do ano passado, foram confirmados 660 casos e 210 óbitos……”

Map: South America showing areas at risk for Yellow Fever Transmision in Columbia, Venezuela, Guyana, Suriname, French Guiana, Brazil, Paraguay, and parts of Ecuador, Peru, Bolivia, Argentina, and Uruguay


Alert – Level 2, Practice Enhanced Precautions in Brazil due to Yellow Fever

CDC

Yellow Fever in Brazil

Map: South America showing areas at risk for Yellow Fever Transmision in Columbia, Venezuela, Guyana, Suriname, French Guiana, Brazil, Paraguay, and parts of Ecuador, Peru, Bolivia, Argentina, and Uruguay
Warning – Level 3, Avoid Nonessential Travel
Alert – Level 2, Practice Enhanced Precautions
Watch – Level 1, Practice Usual Precautions

Key Points

  • There is a large, ongoing outbreak of yellow fever in multiple states of Brazil(https://wwwnc.cdc.gov/travel/destinations/traveler/none/brazil). Since early 2018, a number of unvaccinated travelers to Brazil contracted yellow fever; many of these travelers were infected on the island of Ilha Grande (Rio de Janeiro State). Several have died.
  • Travelers to Brazil should protect themselves from yellow fever by getting yellow fever vaccine at least 10 days before travel, and preventing mosquito bites.
  • In addition to areas in Brazil where yellow fever vaccination has been recommended since before the recent outbreaks, the vaccine is now also recommended for people who are traveling to or living in: All of Espirito Santo State, São Paulo State, and Rio de Janeiro State as well as a number of cities in Bahia State.
  • People who have never been vaccinated against yellow fever should avoid traveling to areas of Brazil where yellow fever vaccination is recommended.
  • Travelers going to areas with ongoing outbreaks may consider getting a booster dose of yellow fever vaccine if it has been 10 or more years since they were vaccinated.
  • Yellow fever vaccine is available at a limited number of clinics in the United States, so travelers should plan ahead to get the vaccine.

What is yellow fever?

Yellow fever is caused by a virus that is spread through mosquitoes. Symptoms of yellow fever (fever, chills, headache, backache, and muscle aches) take 3–6 days to develop. About 15% of people who get yellow fever develop serious illness including bleeding, shock, organ failure, and sometimes death.

What is the current situation?

In early 2017, the Brazilian Ministry of Health reported outbreaks of yellow fever in several eastern states, including areas where yellow fever was not traditionally considered to be a risk. Since the end of 2017, yellow fever cases have reoccurred in several states, especially in the states of Rio de Janeiro, Minas Gerais, and São Paulo, including areas close to the city of São Paulo.

In early 2018, a case of yellow fever was reported in an unvaccinated Dutch traveler who had stayed near the São Paulo metropolitan region. Since then, there have been reports of other unvaccinated travelers to Brazil who visited areas with yellow fever outbreaks and contracted yellow fever; many of these travelers were infected on the island of Ilha Grande (Rio de Janieiro State). Several of these travelers died. None were from the United States.

In response to the outbreak that began in early 2017, the World Health Organization has expanded the list of areas where yellow fever vaccination is recommended for international travelers to Brazil.

In addition to areas in Brazil where yellow fever vaccination has been recommended since before the recent outbreaks, the vaccine is now also recommended for people who are traveling to or living in:

  • All of Espirito Santo State
  • All of São Paulo State, the city of São Paulo and all coastal islands
  • All of Rio de Janeiro State, including the city of Rio de Janeiro and all coastal islands
  • A number of cities in Bahia State

Expanded Yellow Fever Vaccine Recommendation Areas in Brazil

The Brazilian Ministry of Health maintains a regular list of all other cities in Brazil for which yellow fever vaccination has been recommended since before the recent outbreaks. This list does not include recently added areas above. It is located at http://portalsaude.saude.gov.br/images/pdf/2015/novembro/19/Lista-de-Municipios-ACRV-Febre-Amarela-Set-2015.pdf.

What can travelers do to prevent yellow fever?

Get yellow fever vaccine

  • Yellow fever vaccine is the best protection against yellow fever disease, which can be fatal. Anyone 9 months or older who travels to areas where yellow fever vaccine is recommended should be vaccinated against yellow fever at least 10 days before travel. For most travelers, one dose of yellow fever vaccine provides long-lasting protection. However, parts of Brazil are currently higher risk because of the outbreak. Travelers may consider getting a booster dose of yellow fever vaccine if traveling to areas with yellow fever outbreaks and it’s been 10 or more years since they were vaccinated. Areas with outbreaks include the states of Rio de Janeiro, Minas Gerais, and São Paulo.

People who have never been vaccinated against yellow fever for any reason should avoid traveling to areas of Brazil where yellow fever vaccination is recommended.

Yellow fever vaccine is currently available at only a limited number of clinics in the United States. Travelers should contact a yellow fever vaccine provider well in advance of travel. Search for a yellow fever vaccine provider near you(https://wwwnc.cdc.gov/travel/yellow-fever-vaccination-clinics/search).

Yellow fever vaccine is not recommended for some people. Talk with a health care provider if you have questions about the yellow fever vaccine.

Prevent insect bites

Because yellow fever and other diseases are spread by mosquito bites, all travelers to Brazil should prevent mosquito bites by using insect repellent, wearing long-sleeved shirts and pants when outdoors, and sleeping in an air-conditioned or well-screened room or under an insecticide-treated bed net.

If you get sick during or after travel

Talk to a doctor or nurse if you get sick, especially if you have a fever. Tell them you have been in a country with yellow fever.

Additional Information

Clinician Information


Since January 2018, 10 travel-related cases of yellow fever, including four deaths, have been reported in international travelers returning from Brazil.

MMWR

Characteristics of five travelers to Brazil with yellow fever reported by GeoSentinel sites, January–March 2018*Return to your place in the text
Characteristic Patient 1 (man) Patient 2 (woman) Patient 3 (man) Patient 4 (man) Patient 5 (man)
Age (yrs) 46 42 34 44 33
Nationality Dutch French Romanian Swiss German
Reporting site Netherlands France Romania Switzerland United Kingdom
Area (state) of presumed yellow fever acquisition Mairiporã (São Paulo) (Minas Gerais) Ilha Grande (Rio de Janeiro) Ilha Grande (Rio de Janeiro) Ilha Grande (Rio de Janeiro)
Signs/Symptoms Fever, headache, myalgia, nausea, vomiting, diarrhea Fever Fever, rash, myalgia, encephalopathy Fever, petechial rash, arthralgia, vomiting, diarrhea Fever, malaise, nausea, jaundice, hepatomegaly
Clinical/Laboratory findings Hepatitis Hepatitis, thrombocytopenia, neutropenia Renal and hepatic failure Renal and hepatic failure Thrombocytopenia, renal and hepatic failure
Yellow fever diagnostic testing Positive RT-PCR for YFV (urine, whole blood, plasma) Positive RT-PCR (blood); positive IgM (initial diagnosis made in Brazil) Positive PCR (serum, urine); YF IgM positive; IgG titers rising days 4–8 Positive PCR (blood) Positive RT-PCR (serum, urine)
Yellow fever vaccination status No No No No No
Outcome Recovered Recovered Condition improving as of March 15, 2018 Died Died

Brazil is suffering its worst outbreak of yellow fever in decades and is now circling the megacities of Rio de Janeiro and São Paulo, threatening to become this country’s first-blown urban epidemic since 1942.

NY Times

  • The virus kills 3 percent to 8 percent of those who are infected
  • There have been 237 deaths since the hot season began
  • The fatality rate will explode if the virus reaches the slums and the clouds of Aedes aegypti mosquitoes swarming there.
  • Health officials are struggling to vaccinate 23 million people.
  • “…..The vaccine….is highly effective — one dose normally provides lifetime protection. But it is not harmless. It cannot be given to newborns or anyone with a compromised immune system. It is given to people older than 60, pregnant women, or children younger than 8 months only when the risk of infection is high.

    About one recipient in 100,000 suffers a dangerous reaction like jaundice, hepatitis or encephalitis, Dr. Marques said, and about one in a million dies…..”

Map: South America showing areas at risk for Yellow Fever Transmision in Columbia, Venezuela, Guyana, Suriname, French Guiana, Brazil, Paraguay, and parts of Ecuador, Peru, Bolivia, Argentina, and Uruguay

 


Brazil’s Ministry: There are now 723 confirmed cases of yellow fever, including 237 deaths, in that country from Jul 1, 2017, to Feb 28 of this year.

Brazil MOH

“…..As of Feb 27, 5.5 million people in those states had been vaccinated, which is 23.2% of the targeted population…..”


PAHO: Yellow Fever Update in the Americas

PAHO

Situation summary in the Americas

Between January 2016 and January 2018, seven countries and territories of the Region of the Americas reported confirmed cases of yellow fever: the Plurinational State of Bolivia, Brazil, Colombia, Ecuador, French Guiana, Peru, and Suriname. The number of human cases and epizootics collectively reported in this period in the Region of the Americas is the highest observed in decades.

Since the 12 January 2018 Epidemiological Update on Yellow Fever published by the Pan American Health Organization / World Health Organization (PAHO/WHO), Brazil and Peru had reported new yellow fever cases; following is a summary of the situation in both countries.

In Brazil, between 1 July 2017 and 15 February 2018, there were 409 confirmed human cases of yellow fever, including 118 deaths; this figure is lower than what was reported for the same period of the previous year (532 cases including 166 deaths) (Figure 1). In decreasing order, confirmed cases were reported in the states of São Paulo (183 cases, including 46 deaths), Minas Gerais (157 cases, including 44 deaths), Rio de Janeiro (68 cases, including 27 deaths), and in the Federal District (1 fatal case).

During the first four weeks of 2018, a major increase of yellow fever confirmed cases has been observed and reported cases in the states of Sao Paulo and Rio de Janeiro have significantly exceeded the numbers reported in the preceding season, 2016/2017, with cases reported in areas near major cities. In São Paulo, 57% of the confirmed cases had the probable place of infection in a rural area of the municipality of Mairiporã, located 15 kilometers from the northern area of São Paulo city. In Rio de Janeiro, 45% of the confirmed cases are residents of the municipalities of Valença and Teresópolis, the latter located 96 kilometers from the city of Rio de Janeiro. In Minas Gerais, 47% of the confirmed cases reside in the municipalities located to the south and southeast of the city of Belo Horizonte; where no human cases had been detected during the outbreak in the 2016/2017 seasonal period. The probable sites of infection of all the confirmed cases correspond to areas with documented epizootics in non-human primates (NHP).

In addition, two confirmed yellow fever cases (European citizens) have been reported among unvaccinated travelers who had stayed in municipalities of Brazil considered at-risk for yellow fever and where the circulation of the virus has previously been reported.

On 15 February 2018, the Brazil Ministry of Health reported the detection of yellow fever virus in Aedes albopictus mosquitoes captured in rural areas of two municipalities, Ituêta and Alvarenga, of Minas Gerais state in 2017 through an investigation carried out by the Evandro

Pan American Health Organization • http://www.paho.org/ • © PAHO/WHO, 2018
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Chagas Institute. The significance of these findings requires further investigation particularly to confirm vector capacity for transmission.1

To date, there is no evidence that Aedes aegypti is implicated in the transmission.

Figure 1. Distribution of confirmed yellow fever cases by epidemiological week (EW). Brazil, 2016 – 2018

Source: Data published by the Ministry of Health of Brazil and reproduced by PAHO/WHO

With respect to epizootics in Brazil, between 1 July 2017 and 15 February 2018 a total of 3,481 epizootics were reported, representing a greater total than that which was reported during the 2016/2017 outbreak which had a total of 1,659 epizootics.

Of the 3,481 epizootics reported, 499 were confirmed for yellow fever, 1,242 were classified as undetermined (samples were not collected), 1,018 remain under investigation, and 722 were discarded. The state with the highest number of confirmed epizootics is São Paulo (Figure 2). Epizootics were also confirmed in the states of Espiritu Santo, Mato Grosso, Minas Gerais, Rio de Janeiro, and Tocantins. The epizootics occurred in 27 federal entities, including in municipalities that were previously considered as no at-risk for yellow fever.

The number of epizootics reported in the current season is greater than the total reported in the previous season. This situation is compounded by the fact that epizootics are occurring in areas very close to large urban settings such as Sao Paulo and Rio de Janeiro city. The map (Figure 3) shows the advancement of the epizootic wave towards the south of the state of São Paulo. If the epizootic wave repeats the same pattern observed a decade ago—the epizootic wave affected southeastern and southern Brazil and subsequently reached Argentina and Paraguay—this current epizootic wave could reach the neighboring countries again. As part of the response to the outbreak, federal and state authorities are conducting mass vaccination campaigns to immunize susceptible populations. As of 15 February 2018, preliminary results of the mass yellow fever vaccination campaign carried out by the Brazil health authorities – targeting 69 municipalities within the states of Rio de Janeiro (10 million persons in 15 municipalities) and São Paulo (10.3 million in 54 municipalities), indicate that 3.95 1 Brazil Ministry of Health press release, available at: http://bit.ly/2o9yNx4

Pan American Health Organization • http://www.paho.org/ • © PAHO/WHO, 2018
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million persons have been vaccinated for yellow fever (3.6 million persons with fractional doses and 356,800 with standard doses). This figure represents 19.3% of the 20.5 million persons targeted for vaccination within the two states. Due to the low vaccination rate achieved during the campaign in Rio de Janeiro State (12% of the targeted population), state health authorities will extend the campaign and in São Paulo State (26% of the targeted population vaccinated) authorities are assessing the need to extend the campaign for several additional days. In Bahia, the campaign will begin on 19 February with a targeted population to vaccinate of 3.3 million persons in 8 municipalities.

Figure 2. Distribution of epizootics reported per EW. São Paulo, Brazil. EW 26 of 2016 to EW 5 of 2018.

Source: Data published by the São Paulo State Health Secretary, Brazil, and reproduced by PAHO/WHO

Figure 3. Confirmed human cases and municipalities with confirmed yellow fever epizootics. São Paulo, Brazil, July 2017 to 14 February 2018.

Pan American Health Organization • http://www.paho.org/ • © PAHO/WHO, 2018
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In Peru, between EW 1 and 4 of 2018, three probable cases of yellow fever were reported, one of which was confirmed by laboratory. All three cases had no history of yellow fever vaccination.

The first two cases are residents of the city of Pucallpa in the Calleria district, Coronel Portillo Province, Ucayali department, an area considered at-risk for yellow fever. Both had onset of symptoms in EW2 of 2018. The first case died and the second case, spouse of the first case, was discharged and confirmed with yellow fever by Elisa IgM and RT-PCR techniques. The laboratory confirmed case has no history of having travelled outside of the city of Pucallpa; the investigation on the probable place of infection is ongoing accordingly.

The third case, is a resident of the Union Progreso, Inambari District, in the department of Madre de Dios, an area considered to be at-risk for yellow fever. Symptoms onset on EW 4 of 2018; the laboratory results are pending. This case works as a fluvial transporter between the towns of Laberinto, Colorado, and Unión Guacamayo where there are mining camps.

In Peru, between January and December of 2017, there were 14 yellow fever cases reported in 6 departments: 1 in Huánuco, 3 in Ayacucho, 1 in Cusco, 6 in Junín, 1 in Loreto, and 2 in San Martin.

Advice for national authorities

The occurrence of confirmed cases of yellow fever in unvaccinated travelers highlights the need for Member States to reinforce the dissemination of recommendations for international travelers. PAHO/WHO encourages Member States to continue efforts to immunize the at-risk populations and take the necessary actions to keep travelers informed and vaccinated, when heading to areas where yellow fever vaccination is recommended.

On 16 January 2018, the WHO published updated advice, titled, “Updates on yellow fever vaccination recommendations for international travelers related to the current situation in Brazil, information for international travelers,” available at: http://www.who.int/ith/updates/20180116/en/

Vaccination

The yellow fever vaccine is safe and affordable and provides effective immunity against the disease in the range of 80 to 100% of those vaccinated after 10 days and 99% immunity after 30 days. A single dose provides life-long protection against yellow fever disease. A booster dose of yellow fever vaccine is not needed.

Given the limitations on the availability of vaccines and with the aim of promoting the rational use, PAHO/WHO reiterates its recommendations to national authorities:

1. Conduct an assessment of vaccination coverage against yellow fever in areas at risk at the municipal level to guarantee at least 95% coverage2 among the resident population of these areas. 2 Pan American Health Organization. Regional immunization action plan. 54th Directing Council of PAHO, 67th session of the WHO Regional Committee for the Americas; 28 September – 1 October 2015; Washington (DC),

Pan American Health Organization • http://www.paho.org/ • © PAHO/WHO, 2018
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2. Member States that are not currently experiencing outbreaks should not conduct yellow fever immunization campaigns. Priority should be given to the use of vaccines in susceptible populations and to avoid revaccination.

3. Ensure vaccination of all travelers to endemic areas at least 10 days before traveling.

4. Depending on vaccine availabilities, Member States should have a small stock that allows them to respond to outbreaks.

5. Postpone routine vaccination in children in non-endemic areas until sufficient vaccines are available. Once there is availability, catch-up campaigns should be conducted to complete vaccination schedules.

Precautions

It is recommended to individually assess the epidemiological risk of contracting disease when faced with the risk of an adverse event occurring in persons over 60 years who have not been previously vaccinated.

 The vaccine can be offered to individuals with asymptomatic HIV infection with CD4+ counts ≥ 200 cells / mm3 requiring vaccination.

 Pregnant women should be vaccinated in emergency epidemiological situations and following the explicit recommendations of health authorities.

 Vaccination is recommended in nursing women who live in endemic areas, since the potential risk of transmitting the vaccine virus to the child is far lower than the benefits of breastfeeding.

 For pregnant or lactating women traveling to areas with yellow fever transmission, vaccination is recommended when travel cannot be postponed or avoided. They should receive advice on the potential benefits and risks of vaccination to make an informed decision. The benefits of breastfeeding are superior to those of other nutritional alternatives.

The following people are usually excluded from yellow fever vaccination:

• Immunocompromised individuals (Including those with thymus disorders, symptomatic HIV, malignant neoplasms under treatment, and those that are receiving or have received immunosuppressive or immunomodulatory treatments, recent transplants, and current or recent radiation therapy).

• People with severe allergies to eggs and their derivatives.

United States. Washington (DC): PAHO; 2015. Available at: http://www2.paho.org/hq/index.php?option=com_content&view=article&id=13101&Itemid=42296&lang=en

Pan American Health Organization • http://www.paho.org/ • © PAHO/WHO, 2018
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Related Links

 Brazil Ministry of Health. Yellow Fever Reports. Available at: http://bit.ly/2sq3aV6

 PAHO/WHO Yellow Fever. Available at: http://www.paho.org/hq/index.php?option=com_topics&view=rdmore&cid=5514&Ite mid=40784&lang=en

 PAHO/WHO. Guidance on Laboratory Diagnosis of Yellow Fever Virus Infection. Available at: http://www.paho.org/hq/index.php?option=com_docman&task=doc_download&Item id=270&gid=38104&lang=en

 PAHO/WHO. Requirements for the International Certificate of Vaccination or Prophylaxis (ICVP) with proof of vaccination against yellow fever. Available at: http://www.paho.org/hq/index.php?option=com_topics&view=article&id=69&Itemid=4 0784&lang=en

 PAHO Health Emergencies Interactive Atlas and Maps. Available at: http://www.paho.org/hq/index.php?option=com_content&view=article&id=13224%3Ainteractive-atlas-and-maps&catid=3889%3Aaro-contents&Itemid=42337&lang=en


A fractional dose (1/5) of the 17DD yellow fever vaccine: Effective?

 

NEJM

“….In 2016, the response to a yellow fever outbreak in Angola and the Democratic Republic of Congo led to a global shortage of yellow fever vaccine. As a result, a fractional dose of the 17DD yellow fever vaccine (containing one fifth [0.1 ml] of the standard dose) was offered to 7.6 million children 2 years of age or older and nonpregnant adults in a preemptive campaign in Kinshasa. …………

A fractional dose of the 17DD yellow fever vaccine was effective at inducing seroconversion in most of the participants ….”

 


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