Background: This study compared surveillance of cases of sickness absence due to illness caused by influenza and reported in Andalusia and Catalonia in the period 2007-2009.
Methods: A time series of incident cases of sickness absence due to influenza, by sex and age, in which episodes in Andalusia and Catalonia in a previous epidemic period (from 01/01/2007 through 30/09/2009) were compared to the pandemic period (last three months of 2009). The weekly number of new cases of sickness absence due to influenza was calculated, and the minimum, median and maximum values were plotted for each of these two periods.
Results: Unexpectedly, women had a higher proportion of new cases of sickness absence due to influenza during the pandemic period (52.2% in Catalonia and 49.7% in Andalusia). During both periods the 25 to 34 year old age group had a higher number of new cases of sickness absence both in Catalonia (37.439 in the epidemic period and 15.379 in the pandemic) and Andalusia (20.465 epidemic period and 9.630 pandemic period). The arrival of the pandemic was around November (approximately 10.000 cases in Catalonia and 5.000 cases in Andalusia), resulting in a significant increase of cases in contrast to the median of the epidemic period.
Conclusions: During the 2009 pandemic, there was an increase in new cases of sickness absence due to influenza, somewhat greater in Catalonia than Andalusia, with an earlier peak in November, especially among women in these two autonomous communities.