Employers urged to inoculate workers exposed to potentially fatal welding fumes

MOHS is urging local factory bosses to ensure workers are vaccinated against a potentially fatal bacterial disease caused by inhaling welding fumes.

Pneumococcal  pneumonia not only strikes welders but also moulders, coremakers and furnacemen, killing at least two workers each year and hospitalising up to 50 more.

A single one off vaccination is available to help keep affected workers healthy and also ensure employers are compliant with current health and safety legislation.

In a guide published by Dr Jacquie Halliday-Bell, one of MOHS’s sessional occupational health physicians,  workers are advised to have the vaccination after the department of health identified a link between welding fumes and the development of pneumococcal pneumonia.

“The vaccination, PPV23, is safe to use and works by developing good antibodies in healthy workers three weeks after immunisation.

“The cost per vaccination is around £30 so for a relatively low outlay, employers can help safeguard workers exposed to welding fumes and ensure they meet their duty of care obligations.

Dr Halliday-Bell also recommends good control of workplace exposure to minimise the risks, including effective local exhaust ventilation in affected working environments, appropriate personal protective equipment and educating workers, particularly as to the benefits of stopping smoking.

For a limited period, MOHS is offering the PPV23 vaccination at £20 per person. For more information, call Tracey Grove on 0121 601 4041 or email traceygrove@mohs.co.uk.

For the full report, ‘the MOHS guide to immunisation against pneumonia for workers exposed to welding fume’, please see below.

Overview

The Joint Committee on Vaccination and Immunisation (JCVI), produces the Department of Health publication ‘Immunisation against Infectious Disease’, also known as the ‘Green Book’.

The November 2011 edition advises there is a strong association between welding and the development of pneumococcal disease, particularly lobar pneumonia in welders, and added them to the list of patient groups for whom pneumococcal vaccination  (PPV23-purified capsular polysaccharide) can prevent is recommended [1].

 Population at risk

There is an estimated figure of 60,000 welders in the UK.  The HSE estimates that in the UK, even with current access to modern control methods, two welders die each year from pneumococcal pneumonia and 40-50 others are hospitalised due to the disease.  This organism often affects younger as well as older welders. Other occupations with some exposure to metal fume who will also benefit from immunisation, include moulders, coremakers and furnacemen.  It is important to note from the research that the risk of pneumonia appears to be confined to exposed men of working age. An added elevation of mortality from pneumonia has been evident in those working with ferrous metal (due to the iron hypothesis- see below) [2].

Research in Birmingham and West Midlands

Among the evidence reviewed to support the opinion of the Joint Committee was the case control study by Palmer et al (2003) of hospital diagnosed pneumonia cases between 1996–99 in Birmingham and the West Midlands [3].  Across 11 hospitals, 525 men aged 20–64 had community-acquired pneumonia. The study found:

  • Welders had an increased overall rate of pneumonia (adjusted odds ratio (OR) = 1.6, 95% confidence interval (CI) = 1.1–2.4) compared with controls non-exposed controls
  • Risks were highest with exposure in the past year to ferrous fumes (OR for lobar pneumonia = 3.0, 95% CI = 1.4–6.7)
  • A high proportion of confirmed S. pneumoniae lobar pneumonia cases were welders. (OR 3.1 95% CI = 1.0–9.5)

A cohort of 30 427 male Swedish construction workers exposed to metal fume was studied for risks of death from pneumonia. The increased relative risk of S. pneumoniae as the cause was 5.8 compared to other workers [4].

The pathological process

The bacterium Streptococcus pneumoniae, (pneumococcus) is:

  • a common commensal microorganism in the upper respiratory tract in healthy humans
  • there are approximately 90 different serotypes
  • some cause serious infective illnesses, including pneumonia, septicaemia and meningitis
  • these invasive pneumococcal diseases (IPD) carry a significant fatality rate of approximately 5–12% in adults of working age [5,6].

The exact underlying mechanisms leading to infection in welders remains unclear.  Some data suggest that chronic exposure to metal fume blunts responsiveness to inhaled particulate matter through free radical injury of host defenses against infection [7], alternatively inhaled iron may exceed the capacity of the iron binding protein system of the lungs, causing overgrowth of organisms that thrive on it [3].

Risk assessment and controls

Although the dose–response relationship and the level below which exposures should be controlled have not yet been defined, good control of workplace exposure remains the preferred method of managing the risk to workers.  This would include:

  • effective local exhaust ventilation
  • appropriate personal protective equipment
  • effective education of workers to minimise exposure
  • smoking cessation

The risk of pneumonia is significantly lower for those workers who are minimally exposed to metal fume when using automated laser welding/cutting, or hybrid welding.

Pneumococcal vaccination

Several vaccines for pneumococcal pneumonia are available worldwide.  The vaccine offered to children in the UK  is known as the pneumococcal conjugate vaccine.  It prevents infection for seven different serotypes. The vaccine offered to adults, PPV23, contains purified capsular polysaccharide from each of 23 capsular types of pneumococcus.  These 23 account for 96% of the pneumococcal isolates that cause serious infection in the UK.  In addition:

  • the vaccine is safe, and most healthy adults develop a good antibody response to a single dose of PPV three weeks after immunization
  • following a single injection, post-immunisation antibody levels usually begin to wane after about 5 years, although the true potential extent of immunity is unclear
  • it will not prevent pneumococcal pneumonia arising from the 67 or so serotypes not covered by the vaccine
  • it will not prevent pneumonias caused by other microorganisms, or metal fume pneumonitis.

Who to vaccinate and when?

Employees who should be offered vaccination with PPV23:

  • welders
  • moulders
  • coremakers
  • furnacemen etc

Those who will not benefit include those who undertake:

  • plastic, electron beam and friction stir welding
  • metal laser work
  • powder bed deposition
  • cold spray technologies etc

Funding

No Department of Health funding is available for PPV23 to be given in welders, so employers should:

  • treat their responsibility to vaccinate exposed workers as an obligation under the Health and safety at Work Act 1974
  • fund their vaccination programme
  • expect to pay around £30 per vaccination

Timing of vaccination

There is uncertainty regarding the optimum timing of vaccination and the JCVI has not recommended an age restriction.  It can be administered to exposed workers as ‘a one off’, at any age or stage in their career.

Main recommendations:

  • Occupational health providers and employers should offer welders and other employees who are exposed to metal fume a single dose of PPV23
  • Workplace controls should be used to minimise exposure to metal fume as far as reasonably possible.
  •  Exposed workers should be encouraged to discontinue or avoid taking up smoking, to reduce pneumonia, cardiovascular and chronic obstructive pulmonary disease.

References

1. Department of Health. Immunisation against Infectious Disease, 2006 (updated November 2011), Chapter 25 v2_0, p305. http://www.dh.gov.uk/prod_consum_dh/groups/dh_digitalassets/documents/digitalasset/dh_131000.pdf

2. Palmer KT, Poole J, Ayres JG, Mann J, Burge PS, Coggon D. Exposure to metal fume and infectious pneumonia. Am J Epidemiol 2003;157:227–233.

3. K. T. PALMER AND M. P. COSGROVE: VACCINATING WELDERS AGAINST PNEUMONIA 329 Downloaded from http://occmed.oxfordjournals.org/ at University of Southampton on July 5, 2012

4. Torén K, Qvarfordt I, Bergdahl IA, Järvholm B. Increased mortality from infectious pneumonia after occupational exposure to inorganic dust, metal fumes and chemicals. Thorax 2011;66:992–996.

5. Robinson KA, Baughman W, Rothrock G, et al., for the Active Bacterial Core Surveillance (ABCs)/Emerging

Infections Program Network. Epidemiology of invasive Streptococcus pneumoniae infections in the United States,

1995–1998. J Am Med Assoc 2001;285:1729–1735.

6. Burman LA, Norrby R, Trollfors B. Invasive pneumococcal infections: incidence, predisposing factors, and prognosis. Rev Infect Dis 1985;2:133–142.

7. Palmer KT, McNeill Love R, Poole JR et al. Inflammatory responses to the occupational inhalation of metal fume. Eur Resp J 2006;27:366–373.

Dr Jacquie Halliday-Bell, November 2012

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