19may06kl vadheim lecture 41 hib, pneumo, hep a and b medch 401 lecture 4

19May06 KL Vadheim Lecture 4 1

Hib, Pneumo, Hep A and B

MedCh 401

Lecture 4


Haemophilus influenzae b

• Gram negative coccobacillus

• Respiratory pathogen, primarily of children

• Encapsulated and unencapsulated strains

• Unencapsulated strains from respiratory tracts of adults


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


H. influenzae capsule

• Composed of polyribosylribitol phosphate (PRP), a repeating polymer of ribosyl and ribitol phosphate

• Polysaccharide

• Six serotypes, a - f


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)


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


Composition of Hib vaccinesVaccine Component,per 0.5 ml dose

HibTITER(HbOC)Lederle/Wyeth

PedvaxHIB(PRP-OMP)Merck

ActHIB(PRP-T)Sanofipasteur

Comvax(PRP-OMPHepB)Merck

Purified H. influenzaeb capsular saccharide

10 g 7.5 g 10 g 7.5 g

Diphtheria CRM197 25 g

N. meningitidis OMP 125 g 125 g

Tetanus toxoid 24 gAluminum adjuvant 225 g 225 g

Sucrose 8.5%

Sodium borohydrate 35 gNaCl 0.9 % 0.9 %

Preservatives None None NoneClear, colorlesssolution

Slightlyopaque whitesuspension

Lyophilized,with salinediluent

Slightlyopaque whitesuspension


ActHIB

• Lyphilized vaccine

• Reconstituted with:– Saline– DTP (sanofi Pasteur)– DTaP (Tripedia; sanofi Pasteur)


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


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)


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


Streptococcus pneumoniae

• Gram + coccus

• Increasingly resistant to antimicrobial agents

• Commonly occurs as carrier state

• Both capsulated and non-capsulated

• ~90 serotypes


Pneumococcal Vaccines

Component,per 0.5 ml dose

Prevnar (Wyeth) Pneumovax 23 (Merck)

16 g total polysaccharide 575 g total polysaccharideS. pneumoniaecapsularantigens

2 g each:4, 9V, 14, 18C,19F, 23F

4g 6B 25 g each of serotypes: 1, 2, 3, 4, 5, 6B,7F, 8, 9N, 9V, 10A, 11, 12F, 14, 15B, 17F,18C, 19F, 19A, 20, 22F, 23F, 33F

CRM197 20g

Aluminumadjuvant

0.125 mg

Phenol(preservative)

0.25%


Comparative efficacy

• Prevnar - 100%

• Pneumovax - ~57%


Capsular serotypes

• Differ in prevalence


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%


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


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


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


HepA vaccine efficacy

• >95% seropositive after one dose

• 100% seropositive after two doses


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


Hepatitis A Vaccines

Component, per dose Havrix (GSK) Vaqta Merck)

Adult (1ml)

Pediatric(0.5 ml)

Adult(1 ml)

Pediatric(0.5 ml)

Viral antigen 1440 EL.U. 720 EL.U. 50 U 25 U

Aluminum adjuvant 0.5 mg 0.25 mg 0.45 mg 0.225 mg

Sodium Borate 70g 35 g

NaCl 0.9% 0.9%

2-Phenoxyethanol 0.5% 0.5%

Amino acid supplementin PBS

0.3% 0.3%

Polysorbate 20 0.05 mg/ml 0.05 mg/ml

Residual MRC-5 cellproteins

<5g/ml <5g/ml


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


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


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


Hepatitis B Vaccine

• Recombinant

• Old vaccine was pooled human plasma


Hep B Vaccine Manufacturing• Cloned, purified Hepatitis B Surface Antigen

(HBsAg) • Genetically engineered into Saccharomyces

cerevisiae (yeast) cells• Yeast grown in fermenters• HBsAg release by yeast cell disruption• Purified • Formalin-treated (Recombivax only)• Adsorbed to aluminum adjuvants


Hepatitis B VaccinesComponent,

per doseRecombivax HB

MerckEngerix-B

GSK

Pediatric0.5 mldose

Adult1 ml dose

Dialysis1 ml dose

Pediatric0.5 ml

Adult1 ml

Hepatitis B surfaceantigen (HbsAg)

5 g 10 g 40 g 10g 20g

Aluminum adjuvant 0.5 mg 0.5 mg 0.5 mg 0.25 mg 0.5 mg

Thimerosal None None None Trace Trace

NaCl 9 mg/ml 9 mg/ml

19may06kl vadheim lecture 41 hib, pneumo, hep a and b medch 401 lecture 4

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