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Overwhelming infection remains a problem for children who have no spleen either because they were born without one or because they have undergone splenectomy. They are at risk from all encapsulated bacterial pathogens but more than half of invasive infections in these children are caused by Streptococcus pneumoniae. Data on invasive pneumococcal infections have been collected from eight children’s hospitals in the United States since 1993 (Gordon E Schutze and colleagues.
Between September 1993 and August 1999 a total of 2581 episodes of invasive pneumococcal infection were reported, including 26 episodes in 22 children with no spleen (12 congenital asplenia (9 with complex congenital heart disease), 10 post splenectomy). Six (27%) of these 22 children died, five of proved meningitis, and the sixth of suspected meningitis. Of 2476 children with a spleen who had invasive pneumococcal infection 33 (1.3%) died, 17 of meningitis.
Average age at first infection was 12.5 months (congenital asplenia) and 69 months (postsplenectomy). Nine of the 12 children over 2 years old had received the 23-valent polysaccharide pneumococcal vaccine and 18 of the 22 children had been given antibiotic prophylaxis. Presenting signs in the 26 episodes included shock (7), petechiae or purpura (7), disseminated intravascular coagulation (5), and respiratory distress (5). The clinical illnesses were bacteraemia alone (12), meningitis alone (8), bacteraemia with otitis media/sinusitis (3), bacteraemia with pneumonia (2), and meningitis with osteomyelitis (1). Almost half (46%) of isolated pneumococci were nonsusceptible to penicillin and almost 20% were nonsusceptible to ceftriaxone. The new heptavalent conjugate vaccine is expected to improve the protection provided for these children but five of the 26 isolates were of serotypes not present in the conjugate vaccine and one was of a serotype not present in the 23-valent polysaccharide vaccine.
The authors of this report endorse a policy of using both vaccines for children with no spleen. For those under 2 years they recommend the conjugate vaccine followed at 2 years by the polysaccharide vaccine. For those over 2 years they recommend an age-appropriate schedule of immunisation with the conjugate vaccine followed by the polysaccharide vaccine 6 to 8 weeks after the last dose of conjugate vaccine.