No child received influenza vaccine for winter 2003�C04. In nine cases influenza A detection occurred by more than one method, either in respiratory clinical samples or from post-mortem tissues. In eleven cases influenza A virus isolates were recovered. The cultured viruses were analyzed for their antigenic characteristics; all isolates were found to be antigenically similar to each other and to virus isolates recovered from non-fatal cases matched for age, week of infection and geographical location as well as to other circulating strains from the same locality. Influenza AH3N2 was MCE Company 857290-04-1 detected by RT-PCR only in five cases. Staphylococcus aureus and Streptococcus pneumoniae in blood were identified in the two cases of clinical sepsis and one case had Streptococcus pneumonia bacterial pneumonia. No other significant bacteriological findings were described. Enterovirus and norovirus were also detected by RT-PCR in two cases. Autopsy reports were 522606-67-3 available for all cases. All cases showed involvement of the airways including congestion, epiglottitis, ulcerative tracheitis, bronchitis, tracheobronchitis bronchopneumonia, pneumonitis, unilateral or bilateral pneumonia. Lung pathology included congestion, intraalveolar haemorrhage, necrosis, diffuse alveolar damage, pulmonary edema, lung infiltrates, pleural effusions, hemorrhagic pneumonia and lung collapse. Extra-pulmonary pathology included two cases with marked cerebral edema suggestive of hypoxia, sepsis in two cases due to Staphylococcus aureus or Streptococcus pneumoniae and myocarditis in two cases. Eight cases showed abnormalities of the lymphoid system, including seven with enlargement of the lymph nodes, thymus or spleen, six with hemorrhagic LN, thymus or spleen and two with starry sky LN indicating an infiltration of macrophages in the lymphoid tissue. No metabolic disorders were recognized ante or post mortem, although one case showed unusual large fiber laryngeal musculature of uncertain significance. Winter 2003�C04 was marked by an unusually high number of severe and fatal cases of influenza in the young, following the emergence of the influenza A H3N2 antigeni
