BCG vaccine

The BCG vaccine is a live attenuated strain of mycobacterium tuberculosis which confers a useful degree of immunity in some individuals. It is given via intradermal injection (1).

• about 4 weeks after the injection a local skin reaction is produced and there may be regional lymphadenopathy in individuals who have developed an immune response to the BCG vaccine. These individuals will have a positive tuberculin test
• BCG vaccination confers up to 80% protection for up to 15 years when given in the schools programme, but in older patients there is a lack of evidence of effectiveness
  
  
• BCG immunisation should be offered to (2):
  • all infants (aged 0 to 12 months) with a parent or grandparent who was born in a country where the annual incidence of TB is 40/100,000 or greater**
    
    
  • all infants (aged 0 to 12 months) living in areas of the UK where the annual incidence of TB is 40/100,000 or greater*
    
    
  • previously unvaccinated children aged one to five years with a parent or grandparent who was born in a country where the annual incidence of TB is 40/100,000 or greater**These children should be identified at suitable opportunities, and can normally be vaccinated without tuberculin testing
    
    
  • previously unvaccinated, tuberculin-negative children aged from six to under 16 years of age with a parent or grandparent who was born in a country where the annual incidence of TB is 40/100,000 or greater **. These children should be identified at suitable opportunities, tuberculin tested and vaccinated if negative (see section on tuberculin testing prior to BCG vaccination)
    
    
  • previously unvaccinated tuberculin-negative individuals under 16 years of age household or equivalent close contacts of cases of sputum smear-positive pulmonary or laryngeal TB (following recommended contact management advice - see National Institute for Health and Clinical Excellence (NICE), 2016)
    
    
  • previously unvaccinated, tuberculin-negative individuals under 16 years of age who were born in or who have lived for a prolonged period (at least three months) in a country with an annual TB incidence of 40/100,000 or greater
    
    
  • Notes:
    • * universal vaccination operates in areas of the country where the TB incidence is 40/100,000 or greater. This is applied for operational reasons since these geographical areas generally have a high concentration of families who come from regions of the world where the TB incidence is 40/100,000 or greater and therefore a higher potential for transmission events. The decision to introduce universal vaccination in an area is based on geography in order to target vaccination to children who may be at increased risk of TB in an effective way. It does not imply that living in areas that have an incidence of TB 40/100,000 or greater puts children at increased risk of TB infection. This is because most infections of children are likely to occur in household settings. In addition, there has been little evidence of TB transmission in schools in the UK
    • **For country information on prevalence see: https://www.gov.uk/government/publications/tuberculosis-tb-by-country-rates-per-100000-people
      
      
  • Individuals at occupational risk (2) People in the following occupational groups, with direct TB patient contact or contact with infectious materials, should be vaccinated with BCG. 1. Healthcare worker (HCW) or laboratory worker, who has either direct contact with TB patients or with potentially infectious clinical materials or derived isolates. 2. Veterinary and staff such as abattoir workers who handle animals or animal materials, which could be infected with TB. BCG is recommended for unvaccinated, tuberculin-negative individuals in these occupations. BCG efficacy data in adults over the age of 35 years is scarce. Nevertheless, because these groups have a high exposure risk, and given the absence of safety concerns, it is likely that benefits outweigh risks for vaccinating individuals over the age of 35 years with BCG. In addition, there are a number of occupational groups who are working with persons at higher risk of acquiring TB. These include staff working with prisoners, homeless persons, persons with drug and alcohol misuse and those who work with refugees and asylum seekers. BCG vaccination may also be considered for these groups. It should be noted that the risk of exposure of HCWs other than those listed in the category above is unlikely to exceed the background risk of TB the general population and therefore vaccination is not routinely required
• the Mantoux test has replaced the Heaf test as the standard method of tuberculin testing (3)
  
  
• NICE state (4):
  • to improve the uptake of BCG vaccination, identify eligible groups (in line with the Department of Health's Green Book) opportunistically through several routes, for example:
    • new registrations in primary care and with antenatal services, or other points of contact with secondary or tertiary care
    • people entering education, including university
    • links with statutory and voluntary groups working with new entrants and looked-after children and young people
    • during contact investigations
  • if people identified for BCG vaccination through occupational health, contact tracing or new entrant screening are also considered to be at increased risk of being HIV-positive, offer them HIV testing before BCG vaccination

BCG may also be used as immunotherapy in some forms of bladder tumours.

Reference:

1. MeReC bulletin (2003);14(3):9-12.
2. Green Book. Chapter 32: Tuberculosis April 2019.
3. Department of Health (July 6th 2005). Changes to the BCG Vaccination Programme. PL/CMO/2005/3, PL/CNO/2005/3, PL/CPHO/2005/3.
4. NICE (January 2016). Tuberculosis.