Welders are at increased risk for invasive pneumococcal disease

Summary 

Background

Welders are at increased risk of pulmonary infection and lobar pneumonia, likely due to significant occupational exposure to metal fumes. We hypothesized that welders would be at increased risk for invasive pneumococcal disease (IPD) compared to the general population.

Methods

A retrospective chart review of all patients with IPD in the province of Alberta, Canada (population approx. 3.3 million) was conducted from 2000 to 2004 to study the epidemiology of IPD.

Results

There were 18 cases identified in welders, giving an attack rate of 22.7 cases per 100 000 population per year (95% confidence interval (CI) 12.23–33.23). Compared with an attack rate of 8.7 cases per 100 000 population per year (95% CI 8.10–9.26) for the general adult population between ages 18 and 65 years, there was a 2.7-fold greater incidence of IPD in welders (95% CI 1.67–4.22, p<0.001). There was an increased prevalence of serotypes 4 and 8 compared to the general population. Eight of 18 cases were caused by serotypes in the 7-valent pneumococcal conjugate vaccine, 11 of 18 cases by serotypes in the 13-valent pneumococcal conjugate vaccine, and 18 of 18 cases by serotypes in the 23-valent pneumococcal polysaccharide vaccine. Seventeen patients had bacteremic pneumococcal pneumonia and one had meningitis; one person died due to infection. Fifteen of 18 patients were either current or former smokers, which was a higher rate than the general population adjusted for age and gender (odds ratio 2.976, 95% CI 0.908–9.729, p=0.084).

Conclusions

Welders, particularly those who smoke, are at increased risk of IPD and should be considered for routine administration of the pneumococcal polysaccharide vaccine. Ongoing workplace measures to reduce exposure to metal fumes and promote smoking cessation should be reinforced.

Keywords: Invasive pneumococcal disease, Pneumococcus, Serotype, Welders, Vaccine