Access to yellow fever travel vaccination centres in England, Wales, and Northern Ireland: A geographical study
Introduction
The populations of England, Wales, and Northern Ireland made more than 60 million trips abroad in 2015 [1]. More than 700,000 of these trips were made to countries endemic for yellow fever, a potentially deadly, tropical disease transmitted by mosquitoes. The disease is preventable by vaccination and this study was undertaken to elucidate the geographical accessibility of yellow fever vaccination centres.
Yellow fever control has been on the international public health agenda since 1851 and has remained a disease under tight international surveillance and control measures ever since together with diseases such as cholera, and pneumonic plague [2]. Due to its reservoir in monkey and other non-human primate populations in the rain forests of Africa and South America (the forest cycle is maintained with tree-living mosquitoes as vectors), yellow fever may never be eradicated [3]. The main control measure for yellow fever is therefore vaccination in combination with vector control in high risk areas as well as measures available to countries at risk of importing or exporting the disease such as vaccination certificate requirements, border vaccination, and emergency quarantine restrictions to reduce the international spread of the disease [2], [4], [5].
Occasionally, there are large outbreaks in urban areas (urban cycle), where the transmission depends on the Aedes aegypti mosquito, which has spread in cities across the tropics in recent decades. A yellow fever outbreak in Angola and Democratic of Republic of Congo (DRC) in 2015–2016 with more than 7000 suspected cases (965 confirmed cases and 137 confirmed deaths) was a stark reminder of the emerging threat of urban yellow fever outbreaks [6], [7]. Increased international travel, urbanisation, and the fact that many tropical countries have large unvaccinated populations make the prospects of new urban yellow fever outbreaks a particular concern. At least 42 cases of international spread were recorded in connection with the Angola-DRC outbreak to countries with vector presence and largely unvaccinated populations including China and Kenya [8].
Despite vector control efforts and vaccination campaigns, large, cyclical sylvatic outbreaks continue to affect some countries [9]. In early 2017, a sylvatic outbreak in Brazil spread into states where transmission is rarely or not previously reported. As of 31 May 2017, a total of 792 confirmed cases with 274 confirmed deaths had been reported [10]. A mass vaccination programmes was set up to stop the spread into cities. A move that has been seen against the back cloth of recent large urban outbreaks of similar mosquito-borne diseases in Brazil, i.e. chikungunya, dengue, and Zika virus [9].
The National Travel Health Network and Centre (NaTHNaC) has overseen the registration, training, clinical standards, and audit of yellow fever vaccination centres in England, Wales, and Northern Ireland in compliance with the International Health Regulations for yellow fever since 2005 [11] and this is the first study to evaluate the geographical accessibility [12] of the yellow fever vaccination services. The aims of the study were thus to map and ascertain the geographical accessibility of yellow fever vaccination centres, match the number of trips to countries with yellow fever risk to the number of vaccinations given per region, identify any underserved populations and evaluate any need to regulate service provision, and gather data to support contingency planning in the event of a vaccine shortage.
Section snippets
Methods
Administrative data on the postcode location of yellow fever vaccination centres were extracted from the Yellow Fever Vaccination Programme database (NaTHNaC, 27 October 2016). Occupational Health departments (N = 218) were excluded as these by definition were not open to the general public. A total of 3222 centres were registered. General practitioner (GP) practices were the most frequent type of centre (N = 2381). Of the 3222 centres, 3208 or 99.6% could be geo-located to Census 2011 lower
Results
The population weighted mean distance to nearest centre varied from 0.6 km in London to 7.1 km in Northern Ireland. The national mean distance was 2.4 km and the maximum distance 30.9 km. Only 1% of the general population had more than 16.1 km to their nearest centre (99th percentile) (Table 1, Fig. 1, Fig. 2).
A total of 713,548 trips to countries with yellow fever transmission risk were made by residents in England, Wales, and Northern Ireland in 2015 (Table 2). Nigeria (20.7%), Brazil
Discussion
This is the first study to look at the geographical accessibility of yellow fever vaccination centres in England, Wales, and Northern Ireland. For comparison, recent studies of geographical accessibility to GP practices and pharmacies found that 84.8% of the general population in England and Wales lived within 1.6 km of a GP practice [39]; for pharmacies it was 89.2% [40]. In the present study, only 56% of the population lived within 1.6 km of a yellow fever vaccination centre. For comparison,
Conclusion
The geographical accessibility of yellow fever vaccination centres was good across all major population centres considering that long-haul trips to countries with yellow fever risk are likely to be planned. Vaccines administered was found correlated with the number of trips to yellow fever countries at regional level in England, Wales, and Northern Ireland, which indicate an even service availability. A large variation was found between countries in the number of yellow fever vaccination
Funding
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Conflict of interest
None.
Acknowledgement
The authors are indebted to anonymous health professionals in various countries, who assisted with links to websites with information about yellow fever vaccination centres open to the general public.
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