Pneumococcal vaccine

Streptococcus pneumoniae or pneumococcus is a major pathogen causing meningitis, pneumonia, other invasive infections, and the common infections acute otitis media and sinusitis. The major virulence factor is the polysaccharide capsule, present as one of approximately 90 serotypes. Anticapsular antibodies protect against infection. In 1977 and 1997, vaccines composed of purified capsular polysaccharide from 14- and 23-capsular types, respectively, were licensed for use in those children 2 years of age or older who are at increased risk for invasive pneumococcal infection. These vaccines have limited immunogenicity in infants and young children. Pneumococcal conjugate vaccines in which capsular polysaccharides from a limited number of serotypes are covalently linked to a protein carrier have recently been developed. In preliminary reports of randomized, double-blind control studies, a heptavalent vaccine administered as a series of infections to normal infants was efficacious in the prevention of invasive infections, episodes of lobar pneumonia, and acute otitis media caused by vaccine serotypes.     

Pneumococcal pyomyositis

Pyomyositis is most commonly caused by Staphylococcus aureus. A 25-month-old child developed infection of the biceps brachialis muscle caused by Streptococcus pneumoniae. The child had no underlying immune or anatomic defect.     

Non-vaccine Pneumococcal Serotypes Among Children with Invasive Pneumococcal Disease

Objective

To report the percentage of non-vaccine pneumococcal serotypes and their antibiotic susceptibility pattern in children with invasive peumococcal disease.

Methods

Invasive pneumococcal isolates of children <5 years during January 2007 to December 2016 were serotyped by a co-agglutination reaction and sequential multiplex polymerase chain reaction.

Results

Among the total 170 S. pneumoniae invasive isolates, 54 (31.8%) and 44 (25.9 %) were the serotypes, which are not included in current 10-valent or 13-valent vaccines, respectively. Very low resistance was observed against penicillin (4.5%) and all isolates were susceptible to cefotaxime.

Conclusions

One-fourth to one-third of the S. pneumoniae serotypes in under-five children with invasive pneumococcal disease are not covered by existing pneumococcal vaccines in India.

     

Pneumococcal cellulitis]

Streptococcus pneumoniae as a cause of cellulitis is rarely reported in children and adults. We report on an infant with facial cellulitis due to pneumococci and review already described cases since 1975. The main features of this infection, underlying diseases and problems of diagnostics and therapy are discussed.     

Pneumococcal conjugate vaccine

Pneumococcal infections account for a significant proportion of bacterial infections in infants and children. The growing threat from pneumococci resistant to penicillin and other antimicrobials has led to increased pressure for the development of an effective vaccine. The only vaccine available until recently, a purified polysaccharide vaccine, is limited in that it fails to induce adequate and long-lasting immunity in infants under 2 years of age, the age group most at risk from this disease. Polysaccharide antigens conjugated to certain proteins induce effective immunity with a rapid response to subsequent infection or antigen challenge. The success of the protein-conjugated haemophilus influenzae vaccine supports the strategy of protein-conjugated polysaccharide vaccines. Currently, published trials of conjugated pneumococcal vaccines have shown the effectiveness and safety of these vaccines. Conjugate vaccines also provide protection against otitis media and may eliminate nasopharyngeal carriage of this organism. Widespread use of this vaccine is both cost effective and safe.     

Pneumococcal vaccination of children

Streptococcus pneumoniae is the most frequent cause of invasive bacterial infection in children younger than 2 years of age, reaching a peak incidence at 6 to 12 months of age. Pneumococci also cause many cases of pneumonia, sinusitis, and otitis media. Incidence rates of invasive infection in children with sickle cell disease, acquired or congenital splenectomy, or human immunodeficiency virus infection are 20- to 100-fold higher than are those of healthy children during the first 5 years of life. Other healthy children, such as those of American Indian, Native Alaskan, or African American descent, also have high rates of invasive infection, and those children enrolled in out-of-home care may have modestly increased risks. Pneumococcal polysaccharide polyvalent vaccines have been available for more than 2 decades but are limited in their usefulness for children because of their inability to induce protective antibody responses in children younger than 2 years of age and lack of immunologic memory. In contrast, pneumococcal protein conjugate vaccines induce presumptive protective responses in infants younger than 6 months, and immunologic memory further enhances responses after booster doses are given. Currently, a single heptavalent pneumococcal protein conjugate vaccine is licensed for use in the United States and is recommended for routine administration to all children, beginning at 2 months of age. It also is recommended for children between 24 and 59 months of age who are at high risk of acquiring invasive disease.     

Pneumococcal hemolytic uremic syndrome

We report Hemolytic Uremic Syndrome (HUS) induced by Streptococcus pneumoniae in a 20 month-old girl. She responded well to hemodialysis.     

Pneumococcal revaccination of splenectomized children

Forty-three Danish splenectomized children received a single subcutaneous dose of a 14-valent pneumococcal vaccine (Pneumovax 23; Merck). Blood samples were taken before, 4 weeks after and 5 years after vaccination. Total pneumococcal antibody concentrations as well as antibodies against each of the 14 pneumococcal capsular polysaccharide antigens were measured by the enzyme-linked immunosorbent assay method. Depending on the pneumococcal antibody status 5 years after primary vaccination, the children were either revaccinated with a new 23-valent pneumococcal vaccine or scheduled for reexamination later. The antibody concentrations found 5 years after vaccination showed a strong correlation with the prevaccination antibody concentrations. Revaccination of children with low antibody concentrations 5 years after primary vaccination is safe, is without significant side effects and leads to a satisfactory antibody response.     

Pneumococcal endocarditis in children

Endocarditis caused by Streptococcus pneumoniae in children is an infrecuent disease, corresponding to 3-7 % of all cases reported. Pneumococcal endocarditis is a serious condition with a rapidly destructive nature and high fatality rate, demanding prompt medical and surgical treatment. We report a case an infant eleven years old who was admitted with endocarditis by S. pneumoniae, who presented with hearth failure and required surgery. A review of the literature of endocarditis caused by S. pneumoniae is presented.