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Surveillance Report

16 November 2011

Travel Health: Summary of yellow fever vaccinations given in Scotland: 2010

Introduction

Under the International Health Regulations, yellow fever is currently the only disease for which an International Certificate of Vaccination or Prophylaxis (ICVP) may be required for entry into a defined number of countries.1 The ICVP must be suitably signed and stamped and is valid only where a WHO-approved vaccine has been administered. State signatories to the IHR, of which the United Kingdom is one, are required to designate specific yellow fever vaccination centres (YFVCs) 'in order to ensure the quality and safety of the procedures and materials employed' (Annex 7).2

The statutory responsibility for designating YFVCs in Scotland, as part of the UK, was passed from the Scottish Government to Health Protection Scotland (HPS) in December 2006. Through a programme of registration, training, and audit HPS seeks to maintain and improve overall standards and consistency of practice within YFVCs in Scotland. This contributes both to protecting the health of travellers from Scotland and to ensuring that the UK meets its obligations under the IHR.

YFVCs in Scotland must agree to comply with certain 'Conditions of Registration' in order to become, and remain registered (Box).

Conditions of registration as a Designated YFVC in Scotland
  1. The centre will administer only yellow fever vaccines approved
    by the World Health Organization (WHO).
  2. All yellow fever vaccinations carried out at the centre will be
    performed by the responsible medical practitioner, or by a
    suitably qualified person (nurse or doctor) acting under his/
    her direction and control.
  3. Facilities for administering and storing vaccines will be of an
    acceptable standard.
  4. Appropriate policies for safe administration of yellow fever
    vaccine will be in place, and all staff involved in administration
    of vaccine will be appropriately trained.
  5. The centre will comply with staff training as required by Health
    Protection Scotland (HPS).
  6. The centre will keep appropriate records of all vaccinations
    administered.
  7. The International Certificate of Vaccination or Prophylaxis will
    be completed in accordance with WHO International Health
    Regulations (IHR), bearing a specified YFVC registered stamp
    and signed by an authorised vaccinator.
  8. All vaccine associated adverse events will be reported to
    the Medicines and Healthcare Products Regulatory Agency
    (MHRA).
  9. Annual returns of vaccine utilisation will be sent to HPS.
  10. HPS will be notified immediately of any changes, which may
    affect the centre’s registration status.
  11. If requested, HPS will be given access to the centre or receive
    copies of YFVC records to ensure that the centre is complying
    with the conditions of registration.
  12. The centre’s status as a designated YFVC will be reviewed
    biennially

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

One of the duties of any designated YFVC in Scotland is to keep appropriate records of all yellow fever vaccine they administer for a period of 10 years, submitting both annual returns of vaccine utilisation and any adverse event reports to HPS on an annual basis. Here we report on the third year of returns, for the period 1 January to 31 December 2010.

Methods and analysis

218 YFVCs were registered with HPS in 2010, compared with 220 in 2009. All 218 YFVCs submitted a return on number of doses of vaccine administered in that centre for the calendar year 2010 (RR 100%). The data was collated onto a web-based database. For the purpose of this analysis, data was extracted and analysed using Microsoft Excel and MapInfo Professional 8.0. Population data for 2010 was obtained from the General Register Office for Scotland.3

Yellow fever vaccination centres in Scotland in 2010

Of the 218 vaccination centres the majority were in Greater Glasgow & Clyde, Lothian and Grampian NHS Boards; 50 (23%), 38 (17%), and 33 (15%), respectively (Figure 1). Orkney (N=2; 1%), Western Isles (2; 1%), Borders (2; 1%) and Shetland (1; <1%) NHS Boards contributed the smallest number of centres, at 2 (1%), 2 (1%) and 1 (<1%).

In terms of YFVCs per head of population, there were 4/100000 for the whole of Scotland in 2011. By NHS board (Figure 2), Orkney, Western Isles, Highland and Grampian had the highest numbers per head of population at 10/100000, 8/100000, 7/100000 and 6/100000, respectively. Ayrshire & Arran (2/100000), Borders (2/100000) and Lanarkshire (1/100000)had the lowest numbers of centres per head of population.

Doses of YFV administered in YFVCs in Scotland in 2010

In 2010, the 218 YFVCs administered 12511 doses of yellow fever vaccine to travellers, down 1% from 2009 (N=12675) and down 4% from 2008 (13084). The number of doses administered per centre across Scotland ranged from 0 to 975 (Mean +/- standard error = 57+/-7). The majority (67%: 146/218) of the centres administered between 1 and 50 doses (Figure 3), with 5% (11/218) administering no doses, and 3% (7/218) administering over 300 doses in the calendar year 2010.

No adverse events were reported among the 218 YFVCs delivering the 12511 doses, compared with 2 out of 12675 doses in 2009 (see 4).

With respect to distribution of doses by NHS board area (Figure 4), the majority of doses were administered in Grampian (3229 doses, 26% of total), Greater Glasgow & Clyde (2818, 23%) and Lothian (2809, 22%) NHS Boards. Orkney (48, <1%), Western Isles (33, <1%) and Shetland (30, <1%) NHS Boards had the lowest number of doses administered.

For the whole of Scotland 240 doses of yellow fever vaccine were given per 100000 population. Grampian NHS Board had the highest number of doses per head (Figure 5) at 586/100000, followed by Lothian (336/100000) and Orkney (239/100000). The lowest number of doses administered by head of population, were Borders (76/100000), Lanarkshire (74/100000) and Shetland (63/100000) NHS Boards.

Discussion

The current yellow fever vaccine has been available for 70 years,5, 6 being derived from seed lots in turn derived from a 17D strain developed in 1940s.7 Mandatory vaccination in the case of yellow fever is aimed at preventing country-to-country spread of disease, and is often applied to vulnerable countries: being countries without yellow fever disease but where the mosquito vector and monkey host are present.

Under the 1969 International Health Regulations,8 centres vaccinating using yellow fever vaccine were required to be designated by the territorial health administration, and to use yellow fever vaccine approved by the WHO. The 2005 IHR added an additional obligation addressing issues of quality and safety (Annex 7).2 Since being tasked with overseeing the designation of YFVCs HPS has established a Yellow Fever Programme, to facilitate registration, training, monitoring and audit of centres in Scotland, consistent with that for England, Wales and Northern Ireland.

The yellow fever vaccine recommended by WHO is both safe and effective,7 new seed lots being tested for neurovirulence and viscerotropism before being used in production. Few adverse events had been reported as a result of the 400 million doses distributed worldwide by 2005,9 being mostly allergic complications and yellow fever virus-associated neurotropic disease (YEL-AND). YEL-AND was estimated to occur at a rate of 0.4-0.8 cases/100000 doses, being higher in those aged over 60 years.6 However, in recent years another serious adverse event has been noted being yellow fever virus-associated viscerotropic disease (YEL-AVD),6 having an estimated incidence of 0.3-0.4 cases/100000 doses being higher in those with a history of thymus disease and, like YEL-AND, higher in older aged people.6

As in any specialty, before giving a vaccine in travel medicine a health professional will carry out a risk assessment considering not only the risk of any particular disease, but also the risk of the intervention. In the case of yellow fever the chance of the traveller being infected with yellow fever virus via the bite of an infected mosquito must be weighed against the chance of yellow fever vaccination resulting in an adverse event. To aid in the decision making several documents are available:

  1. WHO publications on which countries have a risk of yellow fever transmission and those countries requiring yellow fever vaccination 1, 10, 11
  2. Summary of product characteristics for yellow fever vaccine12
  3. a published estimate of incidence of adverse events due to Yellow fever vaccine.6
  4. Summaries of yellow fever risk and YFVC requirements on a country-by-country basis [www.travax.nhs.uk].

Where YFV is contraindicated or where the risk of adverse reaction is considered greater than that for yellow fever disease but there is a certificate requirement, then an exemption certificate may be considered, although the risk remains that the country they are travelling to may not recognise such a certificate.13

All designated centres sign up to a 'Code of Practice' which stipulates standards which have to be met in relation to safety, training, record keeping and reporting, particularly of adverse events. The absence of any adverse events in 2010 is to be expected when considering published estimates of YEL-AND, YEL-AVD etc, their sporadic nature, and the total number of doses given in Scotland (over 38000 since the beginning of 2008). Reporting of these could however be improved by asking YFVCs to report adverse events as they happen rather than on an annual basis and HPS plans to improve how this data is reported in the future.

In terms of YFVCs it is worth noting that all NHS boards have at least one YFVC; in 2009 Shetland did not have a YFVC.4 Greater Glasgow and Lothian NHS Boards together contained 40% of Scotland's YFVCs while Grampian had a further 15% (Figure 1); the location of the oil industry in Grampian often requiring those involved in the oil industry to travel to yellow fever risk destinations. In terms of YFVCs per head of population (Figure 2) Orkney and Western Isles had the highest number at 10/100000 and 8/100000 respectively related to two centres serving small populations, while Lanarkshire NHS Board had the lowest number at 1/100000 based on seven YFVCs.

The role of the oil industry may play a role in Grampian having the largest numbers of doses (3229; 26% of the Scottish total) and numbers of doses per head of population (586/100000); there was no way to determine the proportion of individuals who received YFV outwith their health board area of residence.

In conclusion, designated YFVCs continue to comply with conditions of registration. It is hoped through the audit process that improvements may be made both in practice and in knowledge so that services may be further improved.

Further detail on the Scottish Yellow Fever Programme can be found on the HPS website (http://www.hps.scot.nhs.uk/yellowfever/index.aspx). This includes how to apply for designation as a YFVC in Scotland; downloadable application and information pack; and a list of resources for centres. There is also a YFVC locator function which allows individuals, including members of the public, to search for their nearest YFVCs across Scotland, and view the services on offer.

Acknowledgements

HPS would like to thank the Yellow Fever Vaccination Centres (YFVCs) throughout Scotland who have co-operated with and supported the implementation of the Yellow Fever Programme (YFP).

References

  1. WHO. International Health and Travel. Geneva: World Health Organization, 2011.
  2. WHO. International Health Regulations 2005. Second ed. Geneva: World Health Organization, 2005.
  3. General Register Office for Scotland. Mid-2010 Population estimates. http://www.gro-scotland.gov.uk/statistics/theme/population/estimates/mid-year/2010/index.html: Accessed November 2011.
  4. Travel Health Team. Summary of yellow fever vaccinations given in Scotland: 2009; Laboratory confirmed 'imported' infections. HPS Weekly Report 2010;44(46):456-458.
  5. Barnett E. Yellow Fever: Epidemiology and Prevention. Emerging Infections 2007;44(15 March):850-6.
  6. Staples JE, Gersham M, Fischer M. Yellow fever vaccine: Recommendations of the Advisory Committee on Immunizations Practices (ACIP). MMWR 2010;59(RR07):1-27.
  7. PAHO. Control of Yellow Fever: Field Guide. Scientific and Technical Publications No 603. Washington DC: PAHO, 2005.
  8. WHO. International Health Regulations 1969. Geneva: World Health Organization, 1983.
  9. Monath T. Yellow fever as an endemic/epidemic disease and priorities for vaccination. Bull Soc Pathol Exot 2006;99(5):341-347.
  10. World Health Organization. Yellow fever vaccination recommendations in the Americas, 2010. http://gamapserver.who.int/mapLibrary/Files/Maps/ITH_YF_vaccination_americas.png:  Accessed Novermber 2011.
  11. World Health Organization. Yellow fever vaccination recommendations in Africa, 2010. http://gamapserver.who.int/mapLibrary/Files/Maps/ITH_YF_vaccination_africa.png:  Accessed Novermber 2011.
  12. Sanofi Pasteur MSD. Summary of Product Characteristics: Stamaril. http://www.medicines.org.uk/emc/medicine/9846: Accessed November 2011.
  13. Hardiman M, Wilder-Smith A. The Revised International Health Regulations and Their Relevance to Travel Medicine. Journal of Travel Medicine 2007;14:141-144.
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Author(s): Prepared by: Travel Health Team Vol: 45 No: 46 Year: 2011 Page:

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