Pneumococcal-specific IgG levels after 13-valent pneumococcal conjugate vaccination in Nigerian children with sickle cell disease

Background: Children with sickle cell disease (SCD) are particularly susceptible to pneumococcal infection. Administration of the 13-valent conjugate pneumococcal vaccine which is now available in Nigeria may help to reduce the incidence.Objectives: To determine the serum level of pneumococcal-specific IgG (PIgG) in a cohort of patients with SCD after administration of a single-dose of a 13-valent pneumococcal conjugate vaccine.Methods: The study was conducted between December 2011 and March 2012 among children with SCD aged 5 months to 5 years attending the sickle cell clinic in five public hospitals in Lagos. Altogether, 151 children with SCD and 52 without it (controls) were recruited by convenience sampling from the sickle cell clinics and well-child clinics. Blood samples were collected for PIgG concentrations before and 2 months after a single dose of the Prevenar 13 vaccine. Seroconversion was defined as a fourfold or greater increase in antibody concentration after vaccination while those with PIg...