Bacterial Meningitis
Thomas T. Yoshikawa, Shobita Rajagopalan in Antibiotic Therapy for Geriatric Patients, 2005
The development of an improved vaccine is also a major goal, and a protein conjugate vaccine has been developed for use in children and infants (Prevnar). An interesting effect of the use of this vaccine, which also decreases colonization rates of S. pneumoniae, is that adult infection rates, especially those in older adults, were also decreased by the use of this vaccine in children. This may have a significant beneficial effect on the rates of infection with antibiotic-resistant S. pneumoniae (37). N. meningitidis vaccine is a quadrivalent vaccine in the United States, containing antigenic material for serotypes A, C, Y, and W135. However, it is not of long-lasting efficacy and again research is under way to improve the duration of protection and to extend its efficacy to serotype B. Currently, indications for the use of this vaccine include prior severe meningococcal infection, asplenia, complement deficiency, and planned travel to areas with endemic meningococcal meningitis or planned residence in areas where the disease occurs more frequently. Individuals with close residential exposure to index cases of meningococcal meningitis should be treated with chemoprophylaxis (rifampin 600 mg twice a day for 2 days or a single dose of ciprofloxacin 500 mg) as should contacts, including healthcare workers, exposed to “mucosal splash” from an index case. Patients with this disease should be isolated with droplet-type precautions for the first 24 hr of treatment (15).
Adaptive humoral immunity and immunoprophylaxis
Gabriel Virella in Medical Immunology, 2019
Conjugate vaccines. As previously mentioned, most polysaccharide vaccines have shown poor immunogenicity, particularly in infants. This lack of effectiveness is a consequence of the fact that polysaccharides induce mostly T-independent responses with little immunological memory. This problem appears to be eliminated if the polysaccharide is conjugated to an immunogenic protein, very much like a hapten-carrier conjugate. Hib conjugate vaccine. The first conjugate vaccines to be developed involved the polyribosyl-ribitol-phosphate (PRP) of Haemophilus influenzae type b (Hib). Four conjugate vaccines are available, based on Hib-polysaccharide conjugated to different protein carriers, such as diphtheria toxoid (PRP-D), a diphtheria toxoid-like protein (PRP-HbOC), tetanus toxoid (PRP-T), or meningococcal outer membrane protein (PRP-OMP). All are equally efficient, but to secure the carrier effect, critical for the boosting effect of repeated immunizations, the same vaccine should be used for the primary immunization and boosters.
Streptococcus pneumoniae
Peter M. Lydyard, Michael F. Cole, John Holton, William L. Irving, Nino Porakishvili, Pradhib Venkatesan, Katherine N. Ward in Case Studies in Infectious Disease, 2010
Two vaccines are available to prevent pneumococcal disease. Both consist of the purified capsular polysaccharide. A 23-valent vaccine consisting of capsular polysaccharide from the 23 serotypes that are most commonly isolated from infected patients is recommended for use in children above the age of 2 years and in adults. This vaccine is only 60% effective. Polysaccharides are T-cell-independent antigens and infants below the age of 2 years respond poorly to them. Therefore, for children younger than 2 years of age, a 7-valent conjugate vaccine is recommended. In this vaccine the capsular polysaccharide is conjugated to a protein carrier to render it T-cell-dependent. The protein carrier used is either tetanus toxoid or diphtheria toxoid, themselves vaccine antigens. The 7-valent conjugate vaccine reduces invasive infection in children, yet has little effect on the incidence of otitis media and colonization. The long-term efficacy and benefit of this vaccine are, therefore, unknown.
Relationship between immune response to pneumococcal conjugate vaccines in infants and indirect protection after vaccine implementation
Published in Expert Review of Vaccines, 2019
Efforts to expand the serotype range in the vaccine are ongoing, as currently extended serotype PCVs are being developing (from PCV15 [159] to PCV20 [160]). Inclusion of additional serotypes will aid further reduction of disease in the community, if the additional serotypes behave similarly to those in the current PCVs. However, the vaccines under development include additional serotypes that are all conjugated to a single carrier (mainly CRM197) [159]. Carrier protein overload with CRM197, which is antigenically related to diphtheria toxoid, presents the risk of interference, especially through the mechanism of carrier-induced epitope suppression [161]. Thus, in theory, the inclusion of more serotypes in a conjugate vaccine may result in lower antibody responses for some serotypes, resulting in reduced protection against carriage. Therefore, studies of vaccines under development must specifically investigate serotype-specific immune responses and their effect on the acquisition of vaccine serotypes. Such analyses will ensure continued community-wide reduction in disease.
Trends and health burden of hospitalized acute respiratory infections and impact of Haemophilus influenza immunization in a Tunisian university hospital: a twelve-year study
Published in Libyan Journal of Medicine, 2020
Manel Ben Fredj, Wafa Dhouib, Meriem Kacem, Cyrine Bennasrallah, Ons Mehrez, Hela Abroug, Imen Zemni, Aicha Gardabou, Koubaa Jamel, Slaheddine Chouchene, Naceur Rouatbi, Asma Belguith Sriha
However, there is no conclusive evidence of differences in the immune response to monovalent or combined Hib conjugate vaccines. In fact, a review about the successes and the contribution of hexavalent combination Hib vaccines in Europe from 2000 to 2014; showed a higher acceptance. On the other hand, there are some concerns that this combined form may reduce Hib immunogenicity [38]. Our results may be related to the high Hib vaccine coverage among children born since 2011. This high coverage vaccine provided by combined vaccines is explained by the reduction of injections number for babies and the reduction of visits to health-care centres. In addition, the effect of Hib Conjugate Vaccine on the prevention of pneumonia in hospitalized infants for bronchiolitis was shown by a case-control study [39]. In NVC, male children dominated Hib pneumonia admissions whereas no sex-difference was notified in VC, this result was concordant with conclusions in literature [40].
A primary care physician’s approach to a child with meningitis
Published in Southern African Journal of Infectious Diseases, 2018
I Govender, C Steyn, G Maricowitz, CC Clark, MC Tjale
Visitors to Saudi Arabia arriving for the purpose of Hajj/Umrah or for seasonal work are required to submit a certificate of vaccination with the quadrivalent (ACYW135) vaccine against meningitis, proving the vaccine was administered no less than 10 days before arrival. The conjugate vaccine is the valid option, when available, and confers a protection of at least five years. The vaccine should have been administered not more than five years prior to entry into the country. The conjugate vaccine is licensed for persons between nine months and 55 years old. The responsible authorities in the visitor’s country of origin should ensure that adults and children aged two years and above are given at least one dose of the quadrivalent vaccine and state the name of the vaccine used clearly on the vaccination card.24