Leading cause of invasive infections shifting in kids with sickle cell disease

A study conducted in Europe found that Salmonella has become the leading cause of invasive bacterial infection (IBI) in children with sickle cell disease (SCD), researchers reported yesterday in Pediatrics.

For the study, a team of European researchers analyzed data from 28 pediatric hospitals in five European countries on children with SCD who had IBI episodes from 2014 through 2019. Children with SCD have a higher risk of IBI, and prior to the widespread use of 13-valent pneumococcal conjugate vaccines (PCV13), Streptococcus pneumoniae had been the leading cause of IBI in children with the disease. The aim of the study was to evaluate the causes of IBI post-PCV13 implementation.

The researchers analyzed data on 169 IBI episodes in 156 children (51% girls, median age 7.8 years); 85 of 138 children (62%) had completed PCV13 vaccination. Among the 169 episodes, Salmonella spp. was the main isolated bacteria (44 cases, 26%), followed by S pneumonia (31, 18%) and Staphylococcus aureus (20, 12%). Salmonella was mainly found in osteoarticular infections and in primary bacteremia (45% and 23% of episodes, respectively) and S pneumoniae in meningitis and acute chest syndrome (88% and 50%, respectively).

All S pneumoniae IBI occurred in children under 10 years, including 35% in children 5 to 10 years old. The outcomes were favorable in 129 cases (81%), but 27 (17%) children had complications of infection and three died: two because of S pneumoniae, and one because of Salmonella. The main risk factors for a severe infection were a previous IBI and pneumococcal infection.

A shift in the epidemiology

The authors say this is the first time in a study in high-income countries that S pneumoniae was not the most common cause of IBI in children with SCD, a finding they say suggests a shift in the epidemiology in the post-PCV13 era.

“Although a major goal in children with SCD should be the prevention of Sp [S pneumoniae] infection, IBI due to Salmonella is an emerging problem,” they wrote. “Effective preventive and treatment strategies should be developed, including broader valent pneumococcal vaccines.”