Situation of yellow fever in the world and consequences for travelers

The World Health Organization (WHO) published in October 2021 a review concerning yellow fever (FJ) worldwide in 2020, a year marked by epidemic outbreaks in certain parts of West Africa and byTransmission extended in other areas of Africa and in the Americas.This news aims to describe this epidemiological situation by taking into account the additional data collected in 2021 for Africa and the Americas, and to draw the consequences for the recommendations to provide to travelers.

1. Balance of yellow fever

1.1.Africa

The number of countries that reported FJ outbreaks in Africa had not been so high since 2009. This situation is explained by a lack of vaccination coverage, including in certain countries which have failed to maintain sufficient coverageafter the sometimes old vaccination campaigns initially effective.The Covid 19 pandemic was an additional aggravating factor, in particular between March and August 2020, with impacts on the prevention of the FJ (lack of surveillance and therefore early screening, fall in systematic vaccination actions, interruptions of campaign ofoccasional vaccinations).

WHO, depending on epidemiological data, vaccine coverage and measures of the struggle put in place, categorized the 29 countries of the Africa region at risk of FJ in four groups: (a) countries with epidemic (s)Reported (s), (b) countries with epidemic potential, (c) countries with sporadic cases and (d) countries without a reported case.

has.Country with epidemic (s) reported (s)

There are 6 of them, Ethiopia, Guinea, Nigeria, Uganda, Senegal and South Sudan.

Ethiopia.

In 2020 the country which did not integrate vaccination against the FJ in its vaccination calendar shows vaccination coverage against this 40 % disease (2020).The country has reported 85 suspect cases of FJ (two confirmed cases).An epidemic has reached the guarage area, in the region of nationalities and peoples of the South.No new event was reported in 2021. A vaccination campaign is planned for 2022.

Guinea.

In 2020 the country, whose vaccination coverage against the FJ was 40 % in 2019, reported 54 suspicious cases of FJ (7 confirmed cases).The epidemic has reached a remote rural area, the Koundara district (Boke region).No new event has been reported in 2021. The latest vaccination campaigns previously 2016.

Nigeria.

En 2020 le pays, dont la couverture vaccinale contre la FJ était de 54 % en 2019, a signalé 3 426 cas suspects de FJ (145 cas confirmés). En 2020, l’épidémie concernait des zones rurales dans les États de Bauchi, Benue, Borno, Delta, Ebonyi et Enugu. En 2021, du 1^er janvier au 30 septembre, 1 518 cas suspects ont été signalés dans 36 États et le territoire de la capitale fédérale (FCT). Les 39 cas confirmés en 2021 étaient issus des états suivants : Anambra, Benue, Delta, Enugu, Imo, Kogi, Nasarawa, Niger, Ondo, Osun et Oyo. Des actions de vaccination ont été planifiées pour l’année 2021.

Uganda.

In 2020 the country, which did not integrate the vaccination against the FJ in its vaccination calendar, reported 46 suspicious cases of FJ (10 confirmed cases).The epidemic affects the northwest of the country (border area with the Democratic Republic of Congo (DRC) and South Sudan).No new event was reported in 2021. A vaccination campaign is planned for 2022.

Senegal.

Vaccination coverage is high in this country (88 % in 2020).In 2020, 35 suspect cases of FJ (7 confirmed) were reported there.The epidemic concerned the rural areas of the eastern country.The confirmed cases were identified in three bordering regions of Mauritania and Mali: 4 cases in the Kidira health district (Tambacounda region), a case in that of Thilogne (Matam region), a case in that of Saraya andOne in that of Kedougou (Kedougou region).No new event has been reported in 2021. The latest vaccination campaigns previously 2016.

South Sudan.

In 2020 the country, which did not integrate the vaccination against the FJ in its vaccine calendar, reported 100 suspect cases of FJ (2 confirmed cases).The cases occurred in the county of Kajo Keji.No new event was reported in 2021.

b.Country with epidemic potential

There are three of them, Burkina Faso, Mali and Chad.

Burkina Faso.

In 2020, the FJ vaccination coverage was 85 % estimated in Burkina Faso.Four confirmed cases of FJ were declared in the Cascades region (Sindou and Banfora) and the Eastern region (FADA).No new event has been reported in 2021. The latest vaccination campaigns preceding 2016.

Mali.

FJ vaccination coverage was estimated at 58 % in 2020. A confirmed case was declared to Sikasso.No new event has been reported in 2021. The latest vaccination campaigns previously 2016.

Chad.

FJ vaccination coverage was estimated at only 29 % in 2019. A confirmed case of FJ was declared in the Lai district, Tandjile region.Another confirmed case was reported in 2021. A vaccination campaign is planned for 2022.

vs.Country with sporadic cases

There are four of them, Cameroon, Côte d'Ivoire, Gabon and Togo.

These countries have identified cases in remote rural areas.The WHO notes that there has been no subsequent local spread and that, with the exception of Cameroon (57 %vaccine coverage), these countries have a high -speed yellow fever coverage (69 %, 61 % and 66 % respectively for Côte d'Ivoire, Gabon and Togo), which should reduce the risk of large -scale spread.

However, in 2021, in Cameroon, 19 confirmed cases of FJ were identified.They came from seven different regions, with a total of 15 health districts (DS) affected: Adamaoua region (DS Rural de Ngaoundéré), Center region (DS d'Eséka), Far North region (DS DE MAGA, MOGODE, YAGOUA, KOUSSERI, AND GOULFEY), LITTERAL region (DS YABASSI, Cité des Palmiers), Northern Region (DS Guider, Garoua 1), North West Region (HD Bamenda) and region of the'West (Dschang, Bafang, Malentouen).

Similarly, in Côte d'Ivoire, 3 confirmed cases of FJ were reported in August 2021.

d.Countries without cases reported in 2020

In 2020, the other countries of the Africa region identified by WHO as potentially at risk for the FJ (Angola, Benin, Burundi, Congo, Central African Republic, DRC, Equatorial Guinea, Gambia, Ghana, Guinea Bissau, Kenya, Liberia,Mauritania, Niger, Sierra Leone and Sudan) did not report any FJ cases in 2020.

In 2021, the DRC identified two FJ cases on July 18: a case in a 34-year-old man in the Abuzi health zone, Northern-Ubangi province, and a case in a 47-year-old woman not vaccinated againstThe FJ of the Ango health area, province of Bas Uele.In addition, the confirmation results are pending for three other positive cases positive from the provinces of Ecuador, Kinshasa and North-Ubangi.In the DRC, vaccination coverage was 56 % in 2019 and a vaccination campaign was planned for 2021.

1.2.Americas

In this region, the number of confirmed cases of FJ has been continuously decreasing since the 2017-2018 season.The balance sheet published by the WHO quoted in reference in this news signals confirmed FJ cases between June 2020 and June 2021 among the populations weakly immunized in Brazil, Guyana and Peru.The balance sheet published the same month by the Pan-American Health Organization (PAHO) shows that new cases have been identified in Brazil and Peru as well as in Venezuela.

has.Brazil

A re-emergence of the FJ virus has been reported in the Extra-Amazonian region of Brazil since 2014. WHO considers that the FJ transmission wave continues to spread in the south of the country and a risk of transmissionSelvatique (in the forest) of the FJ persists in the endemic areas.

Human case

Entre juin 2020 et juin 2021, 291 cas ont été suspectés et 8 cas ont été confirmés, dont 3 sont décédés (47 cas sont en cours d’évaluation). Les 8 cas confirmés sont survenus dans l’Etat de Santa Carina en 2021 au sud du pays. Entre le 1^er juillet et le 27 septembre 2021, 17 cas humains suspects de FJ ont été signalés, dont un cas confirmé dans l'État de Pará au nord du pays (un homme de 21 ans résidant dans la municipalité d'Afua) et deux cas en cours d'évaluation.

Epizootics in non -human primates

In November 2020, a new transmission zone was reported in the southern region, with epizootics reported in non -human primates (notably monkeys) in the paraná and Santa Carina states in the south of the country, continuing their way towardsFrom Rio Grande Do Sul, with the possibility of reaching neighboring countries (Argentina and Paraguay).After an increase in the transmission of the FJ to Santa Carina in December 2020, the border state of Rio Grande Do Sul was reached in January 2021 and in February 2021;Cases have been reported in the metropolitan regions of the great Florianópolis and the south of Santa Catarina (State of Santa Carina).

FJ epizootics were also confirmed in the Center-West region from September 2020, alerting the authorities to the risk of FJ spread to new regions.Genomic studies have indicated a different line from the virus compared to that which is reappeared in the extra-Amazonian region from 2014 and which caused epidemics in the southeast and southern regions in recent years.This discovery indicates a new introduction to the virus from the Amazon endemic region.

During the period 2020-2021, most of the confirmed epizootics (88 %) were reported in the southern region of the country (191/218), followed by the Center-West region (24/218), the Southern Region-Sest (2/218) and the northern region (1/218).In March 2021, an epizootic of FJ among non -human primates was confirmed in acre state.During the current surveillance period (from July 1 to September 27, 2021), a total of 198 epizootics was reported in non -human primates, 10 of which were confirmed for the FJ in the States of Minas Gerais, Rio Grande DoSul and Santa Carina (28 are still in investigation).

b.Countries with sporadic cases detected in environments conducive to selvatic transmission (especially near the jungle) and among non -vaccinated populations

In Guyana, two cases, probably Selvatiques, were reported in 2020, both died.

In 2020, Peru notified 9 cases of FJ, 7 of which were confirmed and 3 died.At least one of the deaths occurred in an area where no case of FJ Selvatique had been reported before, but this case remained isolated and no epizootic was reported.Between weeks 1 and 37 of 2021, 14 cases of FJ have been reported, 10 of which have been confirmed (4 probable cases remain under investigation).Of the 14 cases, 85 % are men and 43 % are unaccompanied adults aged 18 to 57.Seven deaths occurred in the departments of Puno (4), San Martín (2) and Loreto (1).

In Venezuela, during week 39 of 2021, 7 cases of FJ were reported, all confirmed in PCR.The probable site of the infection for confirmed cases was the locality of Caracal, a rural parish located south of the municipality of Maturín (State of Monagas).The first reported case is a 16 -year -old pregnant woman with vaccination history.Among the other six cases, five are men aged 24 to 82, all without a history of vaccination.To date, no death has been reported.

Between weeks 32 and 39 of 2021, 10 epizootics were reported in non -human primates, seven in the state of monagas and three in the state of Anzoátegui.Two of the epizootics reported in the state of confirmed monagas in the laboratory were identified 35 km and 150 km from the Maturín urban area.The other eight were confirmed by an epidemiological link.

2. Recommendations for the traveler

The 2021 health recommendations for travelers are clear; Vaccination (stamililic vaccine) against yellow fever (from the age of 9 months) is essential (whether compulsory or not) for a stay in an endemic area (interropical regions of Africa and America South) or epidemic, even in the absence of an administrative obligation. " - And their application, given the effectiveness of the anti -moral vaccine, will make it possible to rule out any risk of FJ if vaccination is practiced more than 10 days before the trip. These endemic areas are defined annually by the WHO and their cartography is accessible on various Internet sites [Centers for Disease Control and Prevention (Africa, South America), National Travel Health Network and Center (Country Cards) ]. Let us also recall that the amendment to appendix 7 (yellow fever) of the international health regulations (2005) of November 2016 extends the period of validity of the international certificate of vaccination against yellow fever and the duration of the protection conferred by vaccination Anti -Marile Under RSI (2005), which spend ten years to life of the vaccinated person.

However, a recall injection remains recommended independently of the exposure level in the following 3 cases:

However, there are important international and infringering spatial variations in the risk relating to yellow fever.Thus, certain types of stay can exhibit the traveler at an increased risk of exposure to the FJ (stay in the middle of the rural or forestry area of endemic zone, stay in an epidemic area).This risk will be all the more important as a high level of protection against mosquito bites is not possible.In this case, general recommendations will require adaptations: the postponement, even the cancellation of the trip, may be the first measure proposed.Other adaptations are possible:

Source: World Health Organization.

Disease: yellow fever

Vaccine: Stamilil

Main reference:

Disease: yellow fever

Vaccine: Stamilil

Main reference: