A TB Action Plan For Scotland: ANNUAL REPORT / 2013

1. Introduction and Background

1.1 Tuberculosis (TB) is a major global health problem. It is an infectious bacterial disease caused by Mycobacterium tuberculosis and it is both preventable and curable. TB frequently affects the lungs and a person with active pulmonary TB who is symptomatic can often spread the disease to others, while a person with latent TB infection is asymptomatic, but can progress to active TB, thus becoming symptomatic and infectious.

1.2 Several global strategies to control TB have been put in place since 1991, including the 2006 World Health Organization (WHO) Stop TB Strategy. These appear to be having an effect because the 2000 United Nations Millennium Development Goal 6 (to 'halt and reverse the [TB] epidemic by 2015') has already been reached in 2013, and global TB mortality has decreased by 41% since 1990.

1.3 However, there is still a lot of work to be done; there were 8.7 million new infections globally in 2011, with 1.4 million preventable deaths.

1.4 In the WHO European Region, TB rates have been decreasing since 2005. However, rates are variable: some states in Eastern Europe have much higher rates than those in the European Union (EU)/European Economic Area (EEA); dual TB/HIV infection rates are increasing; multi-drug resistant (MDR) TB increased 12-13% between 2009 to 2010; and between 2005 to 2010, treatment success rates decreased from 72% to 69% in new cases, and 50% to 48% in previously treated cases.

1.5 To address the issue, the European Centre for Disease Prevention and Control (ECDC) published A Framework Action Plan to Fight TB in the European Union in 2008. The aim is 'To eliminate TB as a public health problem by 2050 (an incidence of less than one case per million population)', and the 2010 follow-up to the framework provides a strategic monitoring framework to measure progress towards that goal.

1.6 In Scotland, TB rates increased from 2005 to 2010 although there has been a slight decline in 2011 and 2012. Against this increase, the Scottish Government published A TB Action Plan for Scotland (hereafter, the Action Plan) in 2011. The Action Plan sets out 42 recommendations covering four broad areas:

• effective laboratory services and diagnostic tools;
• effective clinical services;
• effective surveillance;
• effective public health services.

1.7 This 2013 Annual Report provides an update on the progress made since the Scottish Government published the Action Plan in 2011, and gives recommendations for continued action.

Epidemiological Summary of TB in Scotland

Case numbers and incidence

1.8 In 2012, the Enhanced Surveillance of Mycobacterial Infections (ESMI) scheme received 408 provisional notifications of TB, an annual incidence of 7.7 cases per 100,000 population (95% CI 0.7-0.8) (Figure 1). This was a decrease of 8.9% in the number of cases and a 9.4% decrease in the incidence when compared with 2011. This is an encouraging finding as it represents a continued decrease in the number of cases and incidence of TB reported since 2010. This is in contrast to a stabilisation in case numbers and incidence observed for the whole of the UK in 2012 (8751 cases, 13.9 per 100,000 population).

Figure 1: Case numbers and incidence of TB in Scotland 2000-2012

1.9 Detailed analysis of this data is available in the HPS annual report of ESMI data published in October 2013.

Clinical characteristics

1.10 Of the 408 cases reported in 2012, 53.9% were classified as pulmonary TB and 46.1% as non-pulmonary TB, which is the highest proportion of non-pulmonary and lowest proportion of pulmonary reported since enhanced surveillance began in 2000. The duration of symptoms was known for 87.5% of cases who were symptomatic at diagnosis. Those presenting with non-pulmonary disease were more likely to have been symptomatic for a longer period of time at notification than those presenting with pulmonary disease (20 weeks versus 17 weeks, respectively). Approximately 12.3% (37) of TB cases had been symptomatic for longer than six months at notification.

Demographic information

1.11 The majority of cases were from Greater Glasgow and Clyde (198 cases; 48.5%; 16.3 per 100,000), Lothian (82 cases; 20.1%; 9.7 per 100,000) and Grampian (36 cases; 8.8%; 6.3 per 100,000) NHS Boards. More than half of TB cases occurred in males (249 cases, 61.0%, 9.7 per 100,000 population). Most TB cases occurred in those aged 25-34 years (115 cases; 28.2%; 16.9 cases per 100,000) and fewest in those aged 0-4 years (four cases; 1.0%; 1.4 cases per 100,000). The rate of TB among children aged under five years (which is an accepted indicator of recent transmission) decreased from 4.4 cases per 100,000 in 2011 to 1.4 cases per 100,000 in 2012, with a total of four cases in this age group in 2012 compared to 13 in 2011, suggesting that transmission of TB may be declining in Scotland.

Place of birth and ethnicity

1.12 Place of birth was known for 89.7% of cases. Of these, 56.2% were born outside the UK. As in previous years, Pakistan (44 cases) and India (82 cases) were the most commonly reported countries of birth. Information on the time from their entry into the UK to TB diagnosis showed that 79.2% had entered the UK two or more years before diagnosis; 50.3% had entered five or more years earlier and 25.7% had entered 10 or more years before diagnosis. The mean time between entry and diagnosis was eight years; the median time was five years. Ethnic origin was recorded for 93.1% of cases. The majority were white Caucasian (169; 43.1%), Indian (91; 23.2%), Pakistani (59; 15.1%) and Black African (35; 15.1%).

Risk factors

1.13 Information on risk factors was recorded for the majority of cases (364/408; 89.2%) in 2012. Specific risk factors for TB were identified in 104 cases (28.6%), of whom 18 cases had more than one known risk factor. Risk factors identified in 2012 include alcohol misuse (36 cases; 9.9%), immunosuppression (31 cases; 8.5%), working in healthcare (22 cases; 6.0%), being a refugee (16 cases; 4.4%), homelessness (12 cases; 3.3%), drug misuse (five cases; 1.4%), and residency in a residential or corrective institution (three cases; 0.8%). There was an increase in the number of cases reported to be immunosuppressed, a care worker or homeless, and a decrease in the number of cases reported to be a refugee compared with 2011.

Microbiological results

1.14 In 2012, 91.7% of all cases had specimens sent for culture: 94.1% of pulmonary and 88.8% of non-pulmonary notifications. Of these, 74.3% were confirmed by culture (80.2% of pulmonary and 67.1% of non-pulmonary notifications). Of the culture confirmed cases in 2012, 269 (96.8%) were due to infection with M. tuberculosis, six (2.2%) with M. bovis one (0.4%) with M. africanum, one (0.4%) with M. fortuitum and one (0.4%) with M. abscessus. Two cases were classified as multi-drug resistant, which is consistent with the numbers reported in previous years. There was a small decrease in the number of isolates resistant to isoniazid, 5.5% compared to 6.8% in 2011.

Treatment outcomes¹

1.15 In 2011, 78.6% of all TB cases (with outcome data available) had successfully completed treatment at 12 months. The most common reason for not completing treatment was death (41 cases; 9.5%), being lost to follow up (22 cases; 5.1%) and still being on treatment (20 cases; 4.6%). In total, 43 cases (9.9%) were reported to have died: 26 died before treatment completion, two completed treatment then subsequently died and 15 died having never commenced treatment (having been diagnosed close to or after death).

Migrants and New Entrants from High Risk Countries

1.16 In-migration to Scotland from overseas has been increasing since 2003 but dropped slightly in 2010 to 2011. Out-migration to overseas has dropped three years in a row following a large rise in 2007 to 2008. The figures shown here are from the Long-Term International Migration (LTIM) series produced by the Office for National Statistics (ONS) (Figure 2).

Figure 2: Migration to and from overseas 1991-2011 (ONS Total International Migration)

1.17 As highlighted in Recent Migration into Scotland: The Evidence Base, the Scottish Government does not have control over the flow of non-EEA migrants into Scotland independently from the UK. Following devolution, Section 5 of the 1998 Scotland Act reserved, in the main, 11 key policy areas to Westminster, among them immigration, employment and social security, while devolving most services to the Scottish Parliament. As a result of this division, decisions about levels of migration and access to benefits are made by the UK Government, while key services affected by migration, including health care, education, housing, children's services and policing are the responsibility of the devolved government.

1.18 There is no comprehensive system for counting people into and out of Scotland and there is no reliable data by country of origin on either the stock or flow of individuals. We therefore have to make use of the best proxy sources available. These include the International Passenger Survey, the Annual Population Survey, Worker Registration Scheme and the NHS Central Register. The data presented can have wide confidence intervals especially for country of birth (see examples below). The 2011 Census will have more detailed information on country of birth with univariate data at Council level available in Autumn 2013. More detailed information such as the date of arrival will follow in later releases.

1.19 For the existing stock population of non-UK born individuals in Scotland, for the period January 2011 to December 2011, the five most common countries of birth were Poland (67,000 CI +/- 9,000), India (24,000 CI +/- 5,000), the Republic of Ireland (22,000 CI +/- 5,000), Germany (19,000 CI +/- 5,000) and Pakistan (16,000 CI +/- 4,000).

1.20 The net migration flows between Scotland and overseas countries between mid-2010 and mid-2011 was 25,400 (in-migration 42,300, out-migration 16,900). NHS Lothian and NHS Greater Glasgow had the highest numbers of in-migration with 12,134 and 10,333 respectively, followed by Grampian (6,813), Tayside (4,196), Fife (2,197) and Argyll and Clyde (now part of NHS Greater Glasgow (1,219)). 71% of in-migrants were between 16 and 34 years old.

1.21 Information on National Insurance application numbers for inward migration flows are likely to be underestimated. For example this does not capture the entrants who repeatedly 'cycle' between Scotland and EU countries (e.g. Poland, Portugal) following harvesting/planting/fishing seasons or the dependents of people who apply for a National Insurance number.

1.22 It does not capture the people from Russia and the ex-federation countries (e.g. Latvia, Lithuania) who come in under Polish EU passports (or Polish who come in under German passports).

1.23 The reasons for in-migration include a definite job, looking for work, to accompany/join family members, formal study, asylum and others. An individual is considered a long-term migrant if they stay >1 year in the country. If they are out of the country for >1 year and then return, they are considered a new entrant. Many individuals enter and leave the country several times over the course of several years.