Clustered Cases of Pneumonia among Healthcare Workers over a 1-year Period in Three Italian Hospitals: Applying the WHO SARS Alert

BACKGROUND: The World Health Organization (WHO) has recommended that a severe acute respiratory syndrome (SARS) alert should be raised when two or more healthcare workers (HCW) in the same health care unit fulfil the SARS clinical criteria, with onset of illness in the same 10-day period. However, in a number of European countries (including Italy) data on reasons for sickness absence are not routinely collected within current HCW worker sickness reporting systems, because of concerns about privacy. To help plan for the implementation of the proposed alert system in Italy, we aimed to determine the minimum number of alert cases defining a cluster. PATIENTS AND METHODS: Sickness absences longer than 7 days in HCW employed in three hospitals in 2003, were identified by checking the hospitals’ administrative databases. HCW with onset of illness in the same 10-day period were contacted and asked whether they have been diagnosed with pneumonia. RESULTS: Overall, 273 absences > 7 days were recorded and 36 clusters of at least two absences > 7 days were identified; a total of 94 HCW were involved in these clusters. Only two HCW involved in different clusters, reported pneumonia. CONCLUSION: The occurrence of clusters of two or more cases of pneumonia in HCW in the same hospital unit appears to be an uncommon event, and thus the alert system proposed is not likely to result in large numbers of false positive alerts. However, it may be difficult to implement this alert system in countries where clinical data on sickness absences are not routinely collected, and alternative mechanisms should be considered.