Unpredictable checks of yellow fever vaccination certificates upon arrival in Tanzania.
BACKGROUND
Yellow fever (YF) is a mosquito-borne disease, which can be prevented by vaccination. While YF vaccination (YFV) is not generally recommended for travellers to Tanzania, proof of YFV may be required upon arrival. In April 2013, the World Health Organization concluded that one dose of YFV confers lifelong protection and countries have started to adapt their entry requirements. The traveller's consultant has to balance the risk of YFV and the risk of encountering problems when entering a country without a valid YFV, especially because countries are slowly implementing the requirements.


METHODS
We performed a survey among 421 travellers to Tanzania with a pre-travel consultation at the Travel Clinic of the University of Zurich about their experiences with YFV certificate inspections upon arrival in Tanzania between January and November 2015.


RESULTS
There were three main findings: (i) most vaccine card checks were done while crossing the land border of Tanzania. Inspections were frequently conducted at Arusha airport, less often in Dar es Salaam and Zanzibar. In the latter a significantly larger percentage of individuals arriving by ferry/boat were checked than those arriving by plane. (ii) Checks appeared to be non-systematic. They were also performed in travellers who did not enter Tanzania from a YF-endemic country. No seasonal or daytime pattern could be identified; the thoroughness of checks varied widely. (iii) In the case of travel without valid YFV, an exemption certificate was always accepted. In travellers with neither a valid YFV nor an exemption certificate, travellers reported forced YF vaccination and fines before entry was granted.


CONCLUSIONS
We recommend YFV or a YF exemption certificate for all travellers to Tanzania until further notice. The decision of whether to vaccinate against YF or to issue an exemption should be based on exposure risk to YF infection in other countries during travel.
Department of Public Health, Division of Infectious Diseases/Travel Clinic, Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Hirschengraben 84, Zurich 8001, Switzerland.
Selina
S
Schönenberger
Department of Public Health, Division of Infectious Diseases/Travel Clinic, Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Hirschengraben 84, Zurich 8001, Switzerland.|Department of Medicine and Diagnostics, Swiss Tropical and Public Health Institute, Socinstrasse 57, Basel 4051, Switzerland.
Christoph
C
Hatz
Department of Public Health, Division of Infectious Diseases/Travel Clinic, Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Hirschengraben 84, Zurich 8001, Switzerland.
Silja
S
Bühler
D002568:Certification; D005260:Female; D006291:Health Policy; D006801:Humans; D017589:Immunization Programs; D008297:Male; D013636:Tanzania; D014195:Travel; D057236:Travel Medicine / Q000379:methods*; D014611:Vaccination / Q000379:methods*; D015004:Yellow Fever / Q000517:prevention & control*; D022341:Yellow Fever Vaccine
D022341:Yellow Fever Vaccine
Tanzania; Yellow fever vaccination; country entry requirements; travel medicine; yellow fever exemption certificate