Acta PRdiatr Scand 80: 423-427, 1991
Pneumococcal Infections in Splenectomized Children Are Preventable H. B. KONRADSENand J. HENRICHSEN From the WHO Collaborating Centrefor Reference &Research on Pneumococci, Statens Seruminstitut, DK-2300 Copenhagen, Denmark
ABSTRACT. Konradsen, H. B. and Henrichsen, J. (The WHO Collaborating Centre for Reference & Research on Pneumococci, Statens Seruminstitut, Copenhagen, Denmark). Pneumococcal infections in splenectomized children are preventable. Acta Paediatr Scand 80: 423, 1991. Through the Danish National Patient Registry we identified all children 0-15 years old who had been splenectomized during the period 1979-87 and all children of the same age who, during the same period of time, had been admitted to a hospital because of either meningitis or bacteraemia caused by Streptococcus pneumoniae. We wanted to see whether any of the splenectomized children had developed invasive pneumococcal infection during the observation period. A similar Danish study covering the period 1969-78, when pneumococcal vaccine was not available, has already been published (3). Four per cent of the children splenectomized during that period developed invasive pneumococcal infection in contrast to none of the children splenectomized and vaccinated during the period 1979-87. Since 1982 antibiotic treatment of splenectomized patients running a fever has been recommended, and we show that the program of pneumococcal vaccination and defined antibiotic prophylaxis has been highly efficacious in preventing postsplenectomy infections in children. Key wordp: splenectomy,pneumococci, meningitis, bacterMmia, children, pneumococcal vaccination.
Splenectomized children run an increased risk of acquiring invasive infections with capsulated bacteria, especially Streptococcus pneumoniae. Approximately 5 Yo of splenectomized children develop bacteraemia or meningitis with a mortality of 30-60% (1, 2), indicating that the incidence is 200-600 times higher than in nonsplenectomized individuals (3-5). The risk depends on underlying disease, age of patient at the time of splenectomy and time elapsed since splenectomy. In a small child whose immune system is not yet fully developed the spleen plays a crucial role in the defence against pneumococcal infections. The spleen produces antibodies, stimulates the alternative complement pathway, and abbve all phagocytizes poorly, or not at all, opsonized particles (6). The liver requires specific antibodies in order to carry out phagocytosis as effectively as the spleen and, therefore, cannot take over the role of the spleen in a non-immune person, such as a small child (6). In 1977 a 1Cvalent and in 1983 a 23-valent pneumococcal polysaccharide vaccine was licensed. Clinical studies showed that vaccination was able to provide type-specific protection in both healthy adults and children (7, 8), and splenectomized persons mount a significant antibody response after vaccination (3, 9, 10). It has, however, not been shown conclusively that pneumococcal vaccination prevents infection in splenectomized individuals. We, therefore, decided to determine the incidence of pneumococcal infections in splenectomized and vaccinated children.
424 H . B. Konradsen and J. Henrichsen
Acta Paediatr Scand 80
MATERIALS Since the fall of 1978 all children splenectomized in Denmark have received a pneumococcal vaccination, if possible 2-3 weeks before, otherwise at least 1 week after the operation. The 14valent pneumococcal vaccine was used until August 1984, when the 23-valent vaccine was introduced. The Danish National Patient Registry, which contains the diagnoses of all patients discharged from all Danish hospitals, was used. All children (0-1 5 years old) who were splenectomized during the nine year period 1979-87 were registered, and so were all children in the same age group who, during the same period of time, had been admitted to hospital because of either meningitis or bacteraemia due to pneumococci. Thus, we could compare these groups and see whether any of the splenectomized children developed post-splenectomy pneumococcal infection during the observation period. The following information was gathered concerning the splenectomized children: Age at the time of splenectomy; year of splenectomy; whether the splenectomy was performed due to a trauma or not; sex of the child; and outcome in relation to the operative procedure regardless of underlying disease. If a child had had post-splenectomy infection the following information would have been obtained Age and sex of the child with infection; kind of infection; interval between splenectomy and infection; year of infection; and course of infection. To control that a vast majority of all children with pneumococcal meningitis or bacteraemia were correctly registered we went through the files of all strains of pneumococci, isolated from blood or cerebrospinal fluid, received in our department for typing purposes. Because we receive approximately 90% of all such strains from the whole country, we were thus able to see whether any of the splenectomized children occurred in the files. A similar study has been carried out in Denmark covering the period 1969-78, when none of the children were vaccinated in connection with their splenectomy, because the 14-valent pneumococcal vaccine was not available before June 1978. This study will be used for comparison (3). There is no reason to believe that diagnostic and therapeutic measures used during the two periods are not comparable.
RESULTS The results of the two Danish studies concerning 1969-78 and 1979-87, respectively, are shown in Table 1. None of the 280 children available for follow up, who were splenectomized and vaccinated in the nine-year period, 1979-87, developed post-splenectomy pneumococcal infection, whereas 15 out of the 384 splenectomized children available for follow up in the 10-year period, 1969-78, did. The mean observation time in the first period was 6.2 years (range: months to 13 Table 1. Number of splenectomies and post-splenectomy pneumococcal infections during the time periods 1969-78 and 197947 ~~~~
Post-splenectomy pneumococcal infections Total number splenectomized Patients included in the study Average number of splenectomies per year
1969-78"
1979-87
15 456'
292d
384
280
45.6
Ob
32.4
The results of this period were published by Pedersen (3). p-=0.002 (a two-sided test compared to Poisson distributions). 14 died and 58 could not be traced. 12 died.
Acta Paediatr Scand 80
Preventable infections in splenectomized 425
years), giving a total of 2381 person-years of observation, whereas the mean observation time in our study was 4.3 years (range: months to 9 years), giving a total of 1 237 person-years of observation. Only 3% of the children in our study were observed for less than one year and 55 % were observed for three to nine years. On the average 45.6 splenectomies were performed on children 0-1 5 years old annually during the first period, compared to 32.4 during the second period (Table 1). There are still more boys than girls being splenectomized (ratio: 1.4). The percentage of splenectomies due to trauma has decreased from 56Yo to 41 Yo. Twelve patients died in close relation to their splenectomy in our study period. None of them died from pneumococcal infections. Eight of those who died were splenectomized because of traumatic rupture of the spleen, as were all 14 patients who died in relation to the splenectomy in the first study period. DISCUSSION Pneumococcal polysaccharide vaccine has been documented to provide protection against serious pneumococcal infections in healthy children and adults (7,8), but its protective efficacy in high risk groups, as for example the splenectomized, has not been convincingly proven (9, 11). However, most studies point towards a protective effect of the vaccine in high-risk groups, except for persons with pronounced immunosuppressive conditions (9, 10, 12, 13). Because the types contained in the 14-valent pneumococcal vaccine accounted for less than 80% of the strains isolated from blood and cerebrospinal fluid, Danish physicians in 1982 were recommended to immediately institute antibiotic therapy to splenectomized patients running a fever (14). Although the coverage of the 23valent vaccine is higher (approximately 90% (15)), we have, during the last few years, changed our recommendations regarding prophylactic measures against pneumococcal infections in the splenectomized: Such patients should be vaccinated and told that this results in a reduction of the risk they are running of acquiring serious pneumococcal infections. Because this risk, however, cannot be fully eliminated, penicillin should be prescribed, bought and taken whenever they run a fever, i.e. before seeing a doctor. Of course, we do not know to what extent this piece of advice has been taken. Since bacteraemia and meningitis are severe conditions, all cases must be brought to medical attention. Therefore, we chose to use the Danish National Patient Registry, which contains the diagnosis of all patients discharged from a hospital. As a control we used our own, probably almost complete, files. None of the children splenectomized during 1979-87 were found in any of the two registries, and we, therefore, conclude that neither bacteraemia nor meningitis due to pneumococci occurred among the 280 splenectomized and vaccinated children during the observation period. We cannot exclude, however, that there might have been a few cases of short lasting bacteraemia, where early penicillin treatment have cured the patient who, therefore, was not admitted to hospital. Still, this does not alter the conclusion of this study. In a previous Danish study 15 of 456 splenectomized children (3.3 9'0) developed pneumococcal infections (3); five of them died. The same frequency would have resulted in a total number of 9-10 cases in our study. We have shown that the prophylactic measures in use in Denmark effectively prevent invasive pneumococcal infections in splenectomized children. Vaccination and antibiotic prophylaxis probably act in unison. Previously, we have shown that pneumococcal vaccination leads to an antibody response in sple28 -9 18304
426 H. B. Konradsen and J. Henrichsen
Acta Paediatr Scand 80
nectomized that is comparable to that of non-splenectomized individuals (1 6). Therefore, there is very good reason to believe that immunization is important and that the protective efficacy lies in the range of 70 %. Antibiotic prophylaxis-as used in this country-must therefore also play its role. However, it is inconceivable that this measure alone has led to the remarkable reduction in the number of lifethreatening cases. The problem of compliance with instructions about taking antibiotics is well known. In Denmark, during the last few years, at least 2 out of 9 bone marrow transplant recipients (who do not respond to pneumococcal vaccination), who developed pneumococcal bacteraemia, died, because they did not take their penicillin, in spite of having received exactly the same instructions as we have been giving our splenectomized patients the last few years. We would of course have preferred to be able to determine the relative importance of each of the two prophylactic measures. This, however, will never be possible because a prospective study of either one alone must now be deemed unet hical. The overall incidence of serious invasive pneumococcal infections has increased slightly during our study period. It is difficult to compare the overall incidence of pneumococcal infections of the two study periods due to, amongst other reasons, a more careful registration. From our files, however, it appears most likely that there has also been a slight increase between the two periods. There is a difference in the mean observation time in the two periods, namely 6.2 years versus 4.3 years. The main difference is that many of the children in the first period were observed for seven to thirteen years, whereas, only a few of the children in our study were observed for more than seven years. As found in other studies (1 7-1 9), almost all cases of post-splenectomy pneumococcal infection, encountered by Pedersen, occurred within the first six years after splenectomy. We, therefore, find it reasonable to believe that the differences in the mean observation period between the two periods are of negligible importance. As shown in Table 1 the total number of splenectomies has decreased from 456 in the first to 292 in the second period. Furthermore, the mean age at splenectomy has increased from 8.4 years to 9.4 years. This is probably due to a growing awareness of the importance of trying to preserve the spleen. Elective splenectomy is also postponed as long as possible in the very young. Preserving as much splenic tissue as possible after traumatic rupture of the spleen has in neither of the two study periods been routine procedure in this country. Although animal experiments indicate that residual splenic tissue may offer some protection (20), there is no evidence that points to beneficial effects of implantation of splenic tissue in humans. Our conclusion is that pneumococcal infections in splenectomized children are preventable. Unfortunately, it is not possible to determine the relative ihportance of vaccination and penicillin prophylaxis for ethical reasons. We, therefore, recommend both.
REFERENCES 1 . Wahlby L,,DomellOfL. Splenectomy after blunt abdominal trauma. A retrospective study
of 413 children. Acta Chir Scand 1981; 147: 131-35. 2. Ein SH, Shandling B, Simpson JS et al. The morbidity and mortality of splenectomy in childhood. Ann Surg 1977; 185: 30749. 3. Pedersen FK. Postsplenectomy infection in Danish children splenectomized 1969-78. Acta Paediatr Scand 1983: 72: 589-95.
Acta Paediatr Scand 80
Preventable infections in splenectomized 421
4. Singer DB. Postsplenectomy sepsis. In: Rosenberg HS, Bolande RF, eds. Perspectives in pediatric pathology. Vol 1. Chicago: Yearbook Medical Publishers, 1973. 5. Barret-Connor E. Bacterial infection and sickle cell anemia: An analysis of 250 infections in 166 patients and a review of the literature. Medicine (Baltimore) 1971; 50: 97-1 12. 6. Wara DW. Host defence against Streptococcus pneumoniae: The role of the spleen. Rev Infect Dis 1981; 3: 299-309. 7. Austrian R, Douglas RM, Schiffman G et al. Prevention of pneumococcal pneumonia by vaccination. Trans Assoc Am Physicians 1976; 89: 184-94. 8. Riley ID, Alpers MP, Gratten H, Lehman D, Marshall TF, Smith D. Pneumococcal vaccine prevents death from acute lower-respiratory-tract infections in Papua New Guinean children. Lancet 1986; 11: 877-81. 9. Ammann AJ, Addiego J, Wara DW, Bertram L, Smith WB, Mentzer WC. Polyvalent pneumococcal polysaccharide immunization of patients with sickle-cell anaemia and patients with splenectomy. N Engl J Med 1977; 297: 897-900. 10. Giebink GS, Le CT, Cosio FG, Spika JS, Schiffman G. Serum antibody responses of highrisk children and adults to vaccination with Capsular polysaccharides of Streptococcus pneumoniae. Rev Infect Dis 1981; Suppl 3: 168-77. 11. Broome CV, Facklam RR,Fracer DW. Pneumococcal disease after pneumococcal vaccination: an alternative method to estimate the efficacy of pneumococcal vaccine. N Engl J Med 1980; 303: 549-52. 12. Ammann AJ, Schiffman G, Addiego JE. Immunization of immunosuppressed patients with pneumococcal polysaccharide vaccine. Rev Infect Dis 1981; Suppl 3: 160-67. 13. Bolan G, Broome CV et al. Pneumococcal vaccine efficacy in selected populations in the United States. Ann Intern Med 1986; 104: 1-6. 14. Pedersen FK, Nielsen JL, Andersen V et al. Proposal for prevention of fulminant infection after splenectomy. Ugeskr Laeger 1982; 144: 1453-56. 15. Robbins JB, Austrian R, Lee CJ et al. Considerations for formulating the second-generation pneumococcal capsular polysaccharide vaccine with emphasis on the cross-reactive types within groups. J Infect Dis 1983; 148: 1136-59. 16. Pedersen FK. Antibody response to pneumococcal vaccine in splenectomized children. Acta Pathol Microbiol Immunol Scand [C] 1983; 91: 169-80. 17. Eraklis AJ, Kevy SV, Diamon LK, Gross RE. Hazard of overwhelming infection after splenectomy in childhood. N Engl J Med 1967; 276: 1225-29. 18. Erickson WD, Burgert EO, Lynn HJ. The harzard of infection following splenectomy in children. Am J Dis Child 1968; 116: 1. 19. Smith CH, Erlandson ME, Schulman I, Stern G. Hazard of severe infections in splenectomized infants and children. Am J Med 1957; 22: 390. 20. Alwmark A, Bengmark S, Gullstrand P, Idvall I, Schaltn C. Splenic resection or heterotopic transplantation of splenic tissue as alternatives to splenectomy. Regeneration and protective effect against pneumococcal septicaemia. Eur Surg Res 1983; 15: 217-22. Submitted Dec. 15, 1989. Accepted April 19, 1990
(H. B. K.) The Streptococcus Department Statens Seruminstitut 5 Artillerivej DK-2300 Copenhagen S Denmark
Pneumococcal Infections in Splenectomized Children Are Preventable H. B. KONRADSENand J. HENRICHSEN From the WHO Collaborating Centrefor Reference &Research on Pneumococci, Statens Seruminstitut, DK-2300 Copenhagen, Denmark
ABSTRACT. Konradsen, H. B. and Henrichsen, J. (The WHO Collaborating Centre for Reference & Research on Pneumococci, Statens Seruminstitut, Copenhagen, Denmark). Pneumococcal infections in splenectomized children are preventable. Acta Paediatr Scand 80: 423, 1991. Through the Danish National Patient Registry we identified all children 0-15 years old who had been splenectomized during the period 1979-87 and all children of the same age who, during the same period of time, had been admitted to a hospital because of either meningitis or bacteraemia caused by Streptococcus pneumoniae. We wanted to see whether any of the splenectomized children had developed invasive pneumococcal infection during the observation period. A similar Danish study covering the period 1969-78, when pneumococcal vaccine was not available, has already been published (3). Four per cent of the children splenectomized during that period developed invasive pneumococcal infection in contrast to none of the children splenectomized and vaccinated during the period 1979-87. Since 1982 antibiotic treatment of splenectomized patients running a fever has been recommended, and we show that the program of pneumococcal vaccination and defined antibiotic prophylaxis has been highly efficacious in preventing postsplenectomy infections in children. Key wordp: splenectomy,pneumococci, meningitis, bacterMmia, children, pneumococcal vaccination.
Splenectomized children run an increased risk of acquiring invasive infections with capsulated bacteria, especially Streptococcus pneumoniae. Approximately 5 Yo of splenectomized children develop bacteraemia or meningitis with a mortality of 30-60% (1, 2), indicating that the incidence is 200-600 times higher than in nonsplenectomized individuals (3-5). The risk depends on underlying disease, age of patient at the time of splenectomy and time elapsed since splenectomy. In a small child whose immune system is not yet fully developed the spleen plays a crucial role in the defence against pneumococcal infections. The spleen produces antibodies, stimulates the alternative complement pathway, and abbve all phagocytizes poorly, or not at all, opsonized particles (6). The liver requires specific antibodies in order to carry out phagocytosis as effectively as the spleen and, therefore, cannot take over the role of the spleen in a non-immune person, such as a small child (6). In 1977 a 1Cvalent and in 1983 a 23-valent pneumococcal polysaccharide vaccine was licensed. Clinical studies showed that vaccination was able to provide type-specific protection in both healthy adults and children (7, 8), and splenectomized persons mount a significant antibody response after vaccination (3, 9, 10). It has, however, not been shown conclusively that pneumococcal vaccination prevents infection in splenectomized individuals. We, therefore, decided to determine the incidence of pneumococcal infections in splenectomized and vaccinated children.
424 H . B. Konradsen and J. Henrichsen
Acta Paediatr Scand 80
MATERIALS Since the fall of 1978 all children splenectomized in Denmark have received a pneumococcal vaccination, if possible 2-3 weeks before, otherwise at least 1 week after the operation. The 14valent pneumococcal vaccine was used until August 1984, when the 23-valent vaccine was introduced. The Danish National Patient Registry, which contains the diagnoses of all patients discharged from all Danish hospitals, was used. All children (0-1 5 years old) who were splenectomized during the nine year period 1979-87 were registered, and so were all children in the same age group who, during the same period of time, had been admitted to hospital because of either meningitis or bacteraemia due to pneumococci. Thus, we could compare these groups and see whether any of the splenectomized children developed post-splenectomy pneumococcal infection during the observation period. The following information was gathered concerning the splenectomized children: Age at the time of splenectomy; year of splenectomy; whether the splenectomy was performed due to a trauma or not; sex of the child; and outcome in relation to the operative procedure regardless of underlying disease. If a child had had post-splenectomy infection the following information would have been obtained Age and sex of the child with infection; kind of infection; interval between splenectomy and infection; year of infection; and course of infection. To control that a vast majority of all children with pneumococcal meningitis or bacteraemia were correctly registered we went through the files of all strains of pneumococci, isolated from blood or cerebrospinal fluid, received in our department for typing purposes. Because we receive approximately 90% of all such strains from the whole country, we were thus able to see whether any of the splenectomized children occurred in the files. A similar study has been carried out in Denmark covering the period 1969-78, when none of the children were vaccinated in connection with their splenectomy, because the 14-valent pneumococcal vaccine was not available before June 1978. This study will be used for comparison (3). There is no reason to believe that diagnostic and therapeutic measures used during the two periods are not comparable.
RESULTS The results of the two Danish studies concerning 1969-78 and 1979-87, respectively, are shown in Table 1. None of the 280 children available for follow up, who were splenectomized and vaccinated in the nine-year period, 1979-87, developed post-splenectomy pneumococcal infection, whereas 15 out of the 384 splenectomized children available for follow up in the 10-year period, 1969-78, did. The mean observation time in the first period was 6.2 years (range: months to 13 Table 1. Number of splenectomies and post-splenectomy pneumococcal infections during the time periods 1969-78 and 197947 ~~~~
Post-splenectomy pneumococcal infections Total number splenectomized Patients included in the study Average number of splenectomies per year
1969-78"
1979-87
15 456'
292d
384
280
45.6
Ob
32.4
The results of this period were published by Pedersen (3). p-=0.002 (a two-sided test compared to Poisson distributions). 14 died and 58 could not be traced. 12 died.
Acta Paediatr Scand 80
Preventable infections in splenectomized 425
years), giving a total of 2381 person-years of observation, whereas the mean observation time in our study was 4.3 years (range: months to 9 years), giving a total of 1 237 person-years of observation. Only 3% of the children in our study were observed for less than one year and 55 % were observed for three to nine years. On the average 45.6 splenectomies were performed on children 0-1 5 years old annually during the first period, compared to 32.4 during the second period (Table 1). There are still more boys than girls being splenectomized (ratio: 1.4). The percentage of splenectomies due to trauma has decreased from 56Yo to 41 Yo. Twelve patients died in close relation to their splenectomy in our study period. None of them died from pneumococcal infections. Eight of those who died were splenectomized because of traumatic rupture of the spleen, as were all 14 patients who died in relation to the splenectomy in the first study period. DISCUSSION Pneumococcal polysaccharide vaccine has been documented to provide protection against serious pneumococcal infections in healthy children and adults (7,8), but its protective efficacy in high risk groups, as for example the splenectomized, has not been convincingly proven (9, 11). However, most studies point towards a protective effect of the vaccine in high-risk groups, except for persons with pronounced immunosuppressive conditions (9, 10, 12, 13). Because the types contained in the 14-valent pneumococcal vaccine accounted for less than 80% of the strains isolated from blood and cerebrospinal fluid, Danish physicians in 1982 were recommended to immediately institute antibiotic therapy to splenectomized patients running a fever (14). Although the coverage of the 23valent vaccine is higher (approximately 90% (15)), we have, during the last few years, changed our recommendations regarding prophylactic measures against pneumococcal infections in the splenectomized: Such patients should be vaccinated and told that this results in a reduction of the risk they are running of acquiring serious pneumococcal infections. Because this risk, however, cannot be fully eliminated, penicillin should be prescribed, bought and taken whenever they run a fever, i.e. before seeing a doctor. Of course, we do not know to what extent this piece of advice has been taken. Since bacteraemia and meningitis are severe conditions, all cases must be brought to medical attention. Therefore, we chose to use the Danish National Patient Registry, which contains the diagnosis of all patients discharged from a hospital. As a control we used our own, probably almost complete, files. None of the children splenectomized during 1979-87 were found in any of the two registries, and we, therefore, conclude that neither bacteraemia nor meningitis due to pneumococci occurred among the 280 splenectomized and vaccinated children during the observation period. We cannot exclude, however, that there might have been a few cases of short lasting bacteraemia, where early penicillin treatment have cured the patient who, therefore, was not admitted to hospital. Still, this does not alter the conclusion of this study. In a previous Danish study 15 of 456 splenectomized children (3.3 9'0) developed pneumococcal infections (3); five of them died. The same frequency would have resulted in a total number of 9-10 cases in our study. We have shown that the prophylactic measures in use in Denmark effectively prevent invasive pneumococcal infections in splenectomized children. Vaccination and antibiotic prophylaxis probably act in unison. Previously, we have shown that pneumococcal vaccination leads to an antibody response in sple28 -9 18304
426 H. B. Konradsen and J. Henrichsen
Acta Paediatr Scand 80
nectomized that is comparable to that of non-splenectomized individuals (1 6). Therefore, there is very good reason to believe that immunization is important and that the protective efficacy lies in the range of 70 %. Antibiotic prophylaxis-as used in this country-must therefore also play its role. However, it is inconceivable that this measure alone has led to the remarkable reduction in the number of lifethreatening cases. The problem of compliance with instructions about taking antibiotics is well known. In Denmark, during the last few years, at least 2 out of 9 bone marrow transplant recipients (who do not respond to pneumococcal vaccination), who developed pneumococcal bacteraemia, died, because they did not take their penicillin, in spite of having received exactly the same instructions as we have been giving our splenectomized patients the last few years. We would of course have preferred to be able to determine the relative importance of each of the two prophylactic measures. This, however, will never be possible because a prospective study of either one alone must now be deemed unet hical. The overall incidence of serious invasive pneumococcal infections has increased slightly during our study period. It is difficult to compare the overall incidence of pneumococcal infections of the two study periods due to, amongst other reasons, a more careful registration. From our files, however, it appears most likely that there has also been a slight increase between the two periods. There is a difference in the mean observation time in the two periods, namely 6.2 years versus 4.3 years. The main difference is that many of the children in the first period were observed for seven to thirteen years, whereas, only a few of the children in our study were observed for more than seven years. As found in other studies (1 7-1 9), almost all cases of post-splenectomy pneumococcal infection, encountered by Pedersen, occurred within the first six years after splenectomy. We, therefore, find it reasonable to believe that the differences in the mean observation period between the two periods are of negligible importance. As shown in Table 1 the total number of splenectomies has decreased from 456 in the first to 292 in the second period. Furthermore, the mean age at splenectomy has increased from 8.4 years to 9.4 years. This is probably due to a growing awareness of the importance of trying to preserve the spleen. Elective splenectomy is also postponed as long as possible in the very young. Preserving as much splenic tissue as possible after traumatic rupture of the spleen has in neither of the two study periods been routine procedure in this country. Although animal experiments indicate that residual splenic tissue may offer some protection (20), there is no evidence that points to beneficial effects of implantation of splenic tissue in humans. Our conclusion is that pneumococcal infections in splenectomized children are preventable. Unfortunately, it is not possible to determine the relative ihportance of vaccination and penicillin prophylaxis for ethical reasons. We, therefore, recommend both.
REFERENCES 1 . Wahlby L,,DomellOfL. Splenectomy after blunt abdominal trauma. A retrospective study
of 413 children. Acta Chir Scand 1981; 147: 131-35. 2. Ein SH, Shandling B, Simpson JS et al. The morbidity and mortality of splenectomy in childhood. Ann Surg 1977; 185: 30749. 3. Pedersen FK. Postsplenectomy infection in Danish children splenectomized 1969-78. Acta Paediatr Scand 1983: 72: 589-95.
Acta Paediatr Scand 80
Preventable infections in splenectomized 421
4. Singer DB. Postsplenectomy sepsis. In: Rosenberg HS, Bolande RF, eds. Perspectives in pediatric pathology. Vol 1. Chicago: Yearbook Medical Publishers, 1973. 5. Barret-Connor E. Bacterial infection and sickle cell anemia: An analysis of 250 infections in 166 patients and a review of the literature. Medicine (Baltimore) 1971; 50: 97-1 12. 6. Wara DW. Host defence against Streptococcus pneumoniae: The role of the spleen. Rev Infect Dis 1981; 3: 299-309. 7. Austrian R, Douglas RM, Schiffman G et al. Prevention of pneumococcal pneumonia by vaccination. Trans Assoc Am Physicians 1976; 89: 184-94. 8. Riley ID, Alpers MP, Gratten H, Lehman D, Marshall TF, Smith D. Pneumococcal vaccine prevents death from acute lower-respiratory-tract infections in Papua New Guinean children. Lancet 1986; 11: 877-81. 9. Ammann AJ, Addiego J, Wara DW, Bertram L, Smith WB, Mentzer WC. Polyvalent pneumococcal polysaccharide immunization of patients with sickle-cell anaemia and patients with splenectomy. N Engl J Med 1977; 297: 897-900. 10. Giebink GS, Le CT, Cosio FG, Spika JS, Schiffman G. Serum antibody responses of highrisk children and adults to vaccination with Capsular polysaccharides of Streptococcus pneumoniae. Rev Infect Dis 1981; Suppl 3: 168-77. 11. Broome CV, Facklam RR,Fracer DW. Pneumococcal disease after pneumococcal vaccination: an alternative method to estimate the efficacy of pneumococcal vaccine. N Engl J Med 1980; 303: 549-52. 12. Ammann AJ, Schiffman G, Addiego JE. Immunization of immunosuppressed patients with pneumococcal polysaccharide vaccine. Rev Infect Dis 1981; Suppl 3: 160-67. 13. Bolan G, Broome CV et al. Pneumococcal vaccine efficacy in selected populations in the United States. Ann Intern Med 1986; 104: 1-6. 14. Pedersen FK, Nielsen JL, Andersen V et al. Proposal for prevention of fulminant infection after splenectomy. Ugeskr Laeger 1982; 144: 1453-56. 15. Robbins JB, Austrian R, Lee CJ et al. Considerations for formulating the second-generation pneumococcal capsular polysaccharide vaccine with emphasis on the cross-reactive types within groups. J Infect Dis 1983; 148: 1136-59. 16. Pedersen FK. Antibody response to pneumococcal vaccine in splenectomized children. Acta Pathol Microbiol Immunol Scand [C] 1983; 91: 169-80. 17. Eraklis AJ, Kevy SV, Diamon LK, Gross RE. Hazard of overwhelming infection after splenectomy in childhood. N Engl J Med 1967; 276: 1225-29. 18. Erickson WD, Burgert EO, Lynn HJ. The harzard of infection following splenectomy in children. Am J Dis Child 1968; 116: 1. 19. Smith CH, Erlandson ME, Schulman I, Stern G. Hazard of severe infections in splenectomized infants and children. Am J Med 1957; 22: 390. 20. Alwmark A, Bengmark S, Gullstrand P, Idvall I, Schaltn C. Splenic resection or heterotopic transplantation of splenic tissue as alternatives to splenectomy. Regeneration and protective effect against pneumococcal septicaemia. Eur Surg Res 1983; 15: 217-22. Submitted Dec. 15, 1989. Accepted April 19, 1990
(H. B. K.) The Streptococcus Department Statens Seruminstitut 5 Artillerivej DK-2300 Copenhagen S Denmark
