Hib, Pneumo, Hep A and B

1. Hib, Pneumo, Hep A and B MedCh 401 Lecture 4 KL Vadheim Lecture 4

2. Haemophilus influenzae b • Gram negativecoccobacillus • Respiratory pathogen, primarily of children • Encapsulated and unencapsulated strains • Unencapsulated strains from respiratory tracts of adults KL Vadheim Lecture 4

3. Hib Transmission • Person-to-person • Respiratory droplets, contact with respiratory secretions • Humans are only host • May be carried in respiratory tract for long periods and transmitted to many people before causing disease KL Vadheim Lecture 4

4. H. influenzae capsule • Composed of polyribosylribitol phosphate (PRP), a repeating polymer of ribosyl and ribitol phosphate • Polysaccharide • Six serotypes, a - f KL Vadheim Lecture 4

5. Type b capsule • Antibody to serotype b conferred type-specific protection • Type b strains account for 95% of all strains causing invasive disease ( bacteremia and meningitis) KL Vadheim Lecture 4

6. Hib vaccine efficacy • Incidence of invasive Hib disease in children <5 years of age has dropped from >20/ 100,000 in 1990 to near zero in 2004 KL Vadheim Lecture 4

7. Composition of Hib vaccines KL Vadheim Lecture 4

8. ActHIB • Lyphilized vaccine • Reconstituted with: • Saline • DTP (sanofi Pasteur) • DTaP (Tripedia; sanofi Pasteur) KL Vadheim Lecture 4

9. Hib Conjugates • C. diphtheriae CRM197 - nontoxic variant of diphtheria toxin • Tetanus toxin - toxoided with formalin • Outer Membrane Protein Comples from B11 strain of N. meningiditis serogroup B KL Vadheim Lecture 4

10. Manufacturing processes • H. influenzae grown in fermenters • PRP purified from cells • Conjugates grown in fermenters, proteins purified, tetanus toxin toxoided • Conjugation reactions: • ActHIB PRP covalently bound to tetanus toxoid • HibTITET PRP coupled to CRM197 by reductive amination • PedVaxHIB PRP covalently bound to N. meningitidis outer membrane protein complex (OMPC) KL Vadheim Lecture 4

11. Pneumococcal Disease • Leading cause of morbidity and mortality for all ages, worldwide • U.S. annual incidence: • 15-30 cases/100k • case fatality rate 15-20% • Major cause of : • invasive infections: bacteremia, meningitis • pneumonia, upper respiratory disease, acute otitis media, sinusitis KL Vadheim Lecture 4

12. Streptococcus pneumoniae • Gram + coccus • Increasingly resistant to antimicrobial agents • Commonly occurs as carrier state • Both capsulated and non-capsulated • ~90 serotypes KL Vadheim Lecture 4

13. Pneumococcal Vaccines KL Vadheim Lecture 4

14. Comparative efficacy • Prevnar - 100% • Pneumovax - ~57% KL Vadheim Lecture 4

15. Capsular serotypes • Differ in prevalence KL Vadheim Lecture 4

16. Pneumococcal Vaccines • Serotypes 4, 6B, 9V, 14, 18C, 19F and 23F (Prevnar) have been responsible for ~80% of invasive pneumococcal disease in children <6 • Pneumovax-23 - additional 16 serotypes gains protection against ~10% KL Vadheim Lecture 4

17. Manufacturing Pneumococcal vaccine • Pneumovax 23 - capsular polysaccharides purified from 23 types of S. pneumoniae • Prevnar - capsular polysaccharides from 6 S. pneumoniae serotypes are purified, then conjugated to diphtheria CRM197 protein KL Vadheim Lecture 4

18. Hepatitis A • Systemic viral infection with liver pathology • Symptoms indistinguishable from most other viral hepatitis infections • Incubation period is ~15 - 50 days • Disease may range from asymptomatic, to hepatitis, to fatal infection KL Vadheim Lecture 4

19. HepA Transmission • Fecal-oral transmission • Person-to-person • Infected food or water • Replicates in the liver • Humans are the only natural host • No chronic infection or carrier state • Virus shed in feces ~3 weeks, starting 1-2 weeks before symptoms KL Vadheim Lecture 4

20. HepA vaccine efficacy • >95% seropositive after one dose • 100% seropositive after two doses KL Vadheim Lecture 4

21. Hepatitis A Manufacturing • Attentuated virus is propagated in MRC-5 cells • Cells are harvested by centrifugation • Cells are lysed to form a viral suspension • Virus is inactivated with formalin • Adsorbed onto aluminum adjuvant KL Vadheim Lecture 4

22. Hepatitis A Vaccines KL Vadheim Lecture 4

23. Hepatitis B • Systemic infection with liver pathology • Symptoms indistinguishable from Hepatitis A or other viral hepatitis infections • Can cause primary hepatocellular carcinoma • Lifetime risk of infection: • 100% for high-risk groups (e.g., IV drug users) • <20% for general U.S. population KL Vadheim Lecture 4

24. Hepatitis B Carriers • 200-300 million worldwide • 1-1.25 million in U.S. • 90% of neonates and 6-10% of infected adults will become carriers • Carriers can infect others KL Vadheim Lecture 4

25. Hepatitis B Transmission • No host outside humans (no other reservoir of infection) • Bloodborne transmission • parenteral • mucosal • perinatal • Communicable 1-2 months before and after onset of symptoms KL Vadheim Lecture 4

26. Hepatitis B Vaccine • Recombinant • Old vaccine was pooled human plasma KL Vadheim Lecture 4

27. Hep B Vaccine Manufacturing • Cloned, purified Hepatitis B Surface Antigen (HBsAg) • Genetically engineered into Saccharomycescerevisiae (yeast) cells • Yeast grown in fermenters • HBsAg release by yeast cell disruption • Purified • Formalin-treated (Recombivax only) • Adsorbed to aluminum adjuvants KL Vadheim Lecture 4

28. Hepatitis B Vaccines KL Vadheim Lecture 4