hib, pneumo, hep a and b

19May06 KL Vadheim Lecture 4 1

Hib, Pneumo, Hep A and B

MedCh 401Lecture 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 gN. 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/mlResidual 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

GSKPediatric0.5 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

hib, pneumo, hep a and b

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