Migration, public health and compulsory screening for TB and HIV

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Migration, public health and compulsory screening
for TB and HIV

• Richard Coker
• 8th October 2003

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• The purpose of screening
• Epidemiological trends
• What risk?
• Effective tools, effective policies?
• Will compulsion improve effectiveness?
• Conclusions

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On the agenda

• Read This And Get Angry Sun, 29 Jan 2003
• The Secret Threat to British Lives The
  Spectator, 25 Jan 2003
• No System to Abuse immigration and health care
  in the UK Centre for Policy Studies, May 2003,
• Before Its Too Late A New Agenda for Public
  Health Conservative Party consultation paper,
  August 2003
• Inquiry into Imported Infections Cabinet
  Office, announced Jan 2003
• Migration and HIV Improving Lives in Britain
  All-Party Parliamentary Group on AIDS, July 2003

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Before Its Too Late

• Advocates 3 tests before permission given to
  remain in the UK
• They must not pose a risk of transmitting an
  infectious disease to the public
• They must not create undue demand on restricted
  health resources
• They must not create a long-term drain on the
  public purse
• those entering the UK through the immigration
  system
• would require sic to have such tests at the
  point of application
• and to pay for them, whilst those seeking asylum
  would be
• detained until it was clear the criteria had been
  met

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Purpose of Screening

• To identify individuals with infection in order
  to provide the appropriate care and treatment for
  that individual
• To prevent public health consequences of
  undetected infectious disease through case
  detection

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Tuberculosis key national facts (1)

• Tuberculosis case reports, by geographic
• origin, England and Wales, 1988 - 2000

• Since 1988, number of cases of TB and the rate
  has increased
• Proportion born abroad has also increased
• Poverty, overcrowding, exposure risk
• Treatment of TB costs approx. 6,000

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Tuberculosis key national facts (2)

• Half of those born abroad who develop TB do so
  within 5 years
• Perhaps 0.3 of asylum seekers have TB at port
  screening, and of these only ¼ have infectious
  disease
• Number of cases detected through Heathrow
  represents less than 0.5 of cases
• Asylum seekers represent a fraction of immigrants
  but it is principally asylum seekers who are
  currently screened
• In one study, screening systems failed to
  identify 60 of new immigrants with TB

• Tuberculosis case reports born abroad by time
  since entry into the UK

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Immigrant-associated TB a public health threat?
Correlation between State-Specific Tuberculosis
Case Rates for Foreign-Born Persons and U.S.-Born
Persons in the United States, 1986 to 1993

• Evidence from many sources
• US states with high levels of TB in foreign-born
  persons do not correspondingly have high rates in
  those born in US
• From DNA finger-printing, most TB in London is
  reactivation
• From Denmark a study showed that transmission
  between immigrants and native-born Danes almost
  non-existent

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HIV key facts (1)

• At end 2001, estimated 41,000 adults living with
  HIV in the UK
• Proportion infected through heterosexual sex is
  increasing
• Most heterosexually-acquired HIV is acquired or
  linked to abroad (71 to Africa)

• Heterosexually acquired infection by
• sub-category of heterosexual
• exposure

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Immigrant-associated HIV a public health threat?

• Of 2,046 individuals infected in the UK, at least
  half were infected through heterosexual sex with
  someone originating from outside Europe
• London-based study suggested that 9 of
  heterosexually-acquired HIV in black Africans
  acquired in UK
• Migrants returning
• Potentially many people unaware and unsuspecting
  of their HIV status (black Africans gt white)

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2 cardinal questions

• Does screening detect those with the condition?
• Will screening assist in achieving the desired
  public health objective?

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Does screening detect those with the condition?

• HIV it depends
• TB it depends

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Screening for HIV

• The tests are sensitive and specific
• But focused screening may assume
• That immigrants from high prevalence countries
  have prevalence rates that reflect donor
  countries
• That populations freely able to move dont pose a
  threat (new eastern European border)
• That those not screened will be served by other
  systems (illegal immigrants, transient
  populations)

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X-rays to detect TB
Theoretical population with prevalence rate of 600/100,000 10,000 immigrants screened Theoretical population with prevalence rate of 40/100,000 10,000 immigrants screened
Expected number of cases of disease 60 4
Number of cases of TB detected through X-ray screening 45 3
Number of cases of TB missed through X-ray screening 15 1
Number of people without TB, but classified as having TB 100 100
Proportion of people identified with TB who actually have it 31 3
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X-ray at screening and 6 months later, Swiss
asylum seeker
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Will screening assist in achieving the desired
public health objective?

• TB
• Evidence is lacking
• No clinical trials
• DH-funded transmission and economic model due to
  report shortly
• HIV
• Screening only confers public health benefit if
  effective action follows
• Evidence is lacking

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• Refusing entry to HIV-infected immigrants
• May reduce burden of disease, costs, and future
  transmission
• May stigmatise, ensure evasive practices
• How often should people be screened?
• Illegal in asylum seekers
• Should they be isolated? For how long?
• Does the risk arise because of status or
  behaviour?

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Coercion and protection of the public health
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• Long historical tradition, with little evidence
  of benefit of detention or compulsory screening
• May show that the government is seen to be
  taking firm, decisive action and the epidemic
  appears to be under control (Panos Institute)
• Coercive measures may be counterproductive

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Public Health Authorities Bear the Burden of
Justification
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Conclusion (1)

• Increases in HIV and TB rates are linked to
  immigration, but have been difficult to quantify
• These changes may reflect, in part, global trends
• Most TB occurs in people after entry
• There is probably a substantial population of
  HIV-infected people in the UK unaware of their
  status who pose a public health challenge

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Conclusion (2)

• Evidence-base to support TB screening of
  immigrants is weak
• Screening tests for TB lack validity
• Screening tests for HIV are reliable
• Evidence is lacking regarding screening
  immigrants for HIV
• Significant ethical, moral, legal and practical
  issues are raised with coercive measures
• Coercive screening practices may result in
  unforeseen perverse consequences

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Purpose of Screening

• To identify individuals with infection in order
  to provide the appropriate care and treatment for
  that individual
• To prevent public health consequences of
  undetected infectious disease through case
  detection