Respiratory viral infections in sickle cell anemia: Special emphasis on H1N1 co-infection

Objectives: Patients with sickle cell anemia (SCA) are immunocompromised and at an increased risk of developing infections. Our aim was to establish the clinical, laboratory and radiological manifestations of respiratory viral infections in SCA at Sultan Qaboos University Hospital (SQUH) and assess its impact on the disease morbidity and mortality, with special emphasis on H1N1. Methods: We undertook a retrospective study in SCA patients with respiratory viral infections following up at the Department of Haematology at SQUH. After approval from the local medical research and ethics committee demographic data, clinical, radiological and laboratory parameters were collected and analyzed. Results: In eighty-four SCA patients with one hundred and nine admission episodes for vasooclusive crisis (VOC), molecular diagnostic techniques confirmed one twenty-five respiratory viral infections. Rhinovirus was the most prevalent infection (35.8%), whereas, H1N1 virus infection was seen only in 10.1%. Laboratory investigations revealed a significant fall in the mean hemoglobin, mean WBC and platelet counts from baseline, whereas, there was a significant rise in the mean lymphocyte and retic count, serum LDH and CRP levels during infective episodes (p<0.05, Wilcoxon signed rank test). 32.1% of the VOC episodes progressed to acute chest syndrome (ACS), but in the H1N1 cohort, ACS was seen in only two episodes (18.2%). Conclusions: Rhinovirus was the commonest respiratory virus infections in SCA patients, whereas, parainfluenza 3 was associated with a significant adverse outcome. H1N1 was associated with a mild course. ACS was seen in approximately one third of this group of patients.