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Choosing the Right Vaccine. A brief presentation on hepatitis B & Haemophilus influenzae type b infections and choosing the right vaccines to prevent them. ************. Choosing the Right Vaccine. Guiding principles for choosing to introduce a vaccine Disease burden Cost benefit

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Choosing the right vaccine
Choosing the Right Vaccine

A brief presentation on hepatitis B & Haemophilus influenzae type b infections and choosing the right vaccines to prevent them

************

WHO/V&B/AVI


Choosing the right vaccine1
Choosing the Right Vaccine

  • Guiding principles for choosing to introduce a vaccine

    • Disease burden

    • Cost benefit

    • Affordability

    • Existence of a robust delivery system

    • Availability of a vaccine

    • Quality of available vaccine

WHO/V&B/AVI


Choosing the right vaccine2
Choosing the Right Vaccine

  • WHO’s Expanded Programme on Immunization (EPI)

    • Launched by WHO in 1974

    • Initially 6 target diseases (TB, Diphtheria, Pertussis, Tetanus, Measles, Polio)

    • Hepatitis B added in 1991

    • Hib added in 1998 (for those countries with moderate to high burden of Hib disease)

WHO/V&B/AVI


Choosing the right vaccine sample epi schedule
Choosing the Right Vaccine: Sample EPI Schedule

WHO/V&B/AVI


Choosing the right vaccine3
Choosing the Right Vaccine

  • Hepatitis B disease

    • hepatitis B virus (HBV) is a DNA virus whose natural host is man

    • hepatitis is infection of the liver by the HBV, where the virus predominantly affects the liver cells (hepatocytes)

    • Outcome of infection

      • death from fulminant hepatitis

      • recovery with life-long immunity

      • development of carrier state/chronic disease

WHO/V&B/AVI


Choosing the right vaccine4
Choosing the Right Vaccine

  • HBV Transmission

    • from mother to child (perinatal/vertical)

    • from child to child

    • through unsafe injections & blood transfusions

    • through sexual contact

WHO/V&B/AVI


Choosing the right vaccine5
Choosing the Right Vaccine

  • Global burden of HBV infection

    • Approximately 30% of world’s population or about 2 billion people have evidence of infection

    • About 350 million have chronic HBV infection

    • Annually about 1 million die from chronic liver disease, including cirrhosis & liver cancer

    • HBV infections in infants are frequently asymptomatic

WHO/V&B/AVI


Choosing the right vaccine6
Choosing the Right Vaccine

  • Hepatitis B vaccine

    • Two types available at present- plasma derived and DNA recombinant vaccines

    • But in the next few years, plasma derived HepB vaccine will be phased out

    • Plasma derived vaccine is a blood product whereas DNA recombinant vaccine is genetically engineered

    • Both are equally safe and effective

    • All Vaccine Fund supply is DNA recombinant

WHO/V&B/AVI


Choosing the right vaccine7
Choosing the Right Vaccine

  • Hepatitis B vaccine…contd/

    • Hepatitis B vaccine is available as either only hepatitis B or in combination with other vaccines

    • Combinations of hepatitis B vaccine include DTP-HepB (tetravalent), DTP-HepB+Hib (pentavalent), DTP-HepB-IPV+Hib (hexavalent) & HepB-Hib

WHO/V&B/AVI


Choosing the right vaccine the issue of a birth dose of hepb vaccine
Choosing the Right Vaccine:The issue of a birth dose of HepB vaccine

  • In many countries perinatal transmission from mothers infected with HBV to their infants is a major source of HBV infections

  • Infections occur usually at time of births, in utero transmission is relatively rare.

  • Therefore, the most effective way to prevent perinatal transmission is to give hepatitis B vaccine as soon as possible after birth, preferably within 24 hours

WHO/V&B/AVI


Choosing the Right Vaccine:The issue of a birth dose of HepB vaccine

  • Where feasible, a birth dose should be administered to all infants at birth.

  • However, this is not a practical option in countries where a large proportion of births take place outside health facilities.

WHO/V&B/AVI


Choosing the right vaccine the issue of a birth dose of hepb vaccine1
Choosing the Right Vaccine:The issue of a birth dose of HepB vaccine

  • One alternative is to screen mothers for HBsAg and give a birth dose to those children born to HBsAg positive mothers. But extensive resources are needed to screen pregnant mothers and track infants

  • Another option is to combine HepB vaccine with that of DTP at 6,10 & 14 weeks

  • With this schedule, in countries with high perinatal transmission rates, the rate of decline in prevalence of HBV infection will be slower, but may be more practical and feasible

WHO/V&B/AVI


Choosing the right vaccine the issue of a birth dose of hepb vaccine2
Choosing the Right Vaccine:The issue of a birth dose of HepB vaccine

  • In countries where perinatal transmission is not a major source of infection, administration of a birth dose contributes less to overall reduction of hepatitis b infection.

  • In these countries, the most practical option may be to combine HepB vaccine with that of DTP at 6,10 & 14 weeks

WHO/V&B/AVI


Choosing the right vaccine the issue of a birth dose of hepb vaccine3
Choosing the Right Vaccine:The issue of a birth dose of HepB vaccine

  • The decision on whether to introduce a birth dose of hepatitis b vaccine is largely a function of burden of perinatal transmission and programmatic feasibility of administration of a birth dose.

WHO/V&B/AVI


Choosing the right vaccine8
Choosing the Right Vaccine

  • Haemophilus influenzae type b diseases

    • Hib is a major killer - every year more than 400,000 children die due to Hib disease

    • Six serotypes (types a-f) known to cause disease, but type b is responsible for over 90% of life-threatening Hib infection in children

    • All serotypes live in nose & throat of people and usually do not cause serious disease

    • When they cause serious disease, it is mostly in children under five years of age

WHO/V&B/AVI


Choosing the right vaccine9
Choosing the Right Vaccine

  • The spectrum of Hib diseases

    • Bacterial meningitis

      • major cause of bacterial meningitis in children

      • 3% to 45% of children with meningitis die (difference in developed/developing countries)

      • 19-45% of children with Hib meningitis suffer neurological complications

    • Pneumonia

      • 2nd most common cause of bacterial pneumonia in children less than 5

WHO/V&B/AVI


Choosing the right vaccine10
Choosing the Right Vaccine

  • The spectrum of Hib diseases..contd/

    • Septicaemia

    • Septic arthritis

    • Osteomyelitis

    • Cellulitis

    • Pericarditis

WHO/V&B/AVI


Choosing the right vaccine11
Choosing the Right Vaccine

  • Haemophilus influenzae type b (Hib) vaccine

    • Hib vaccine is known as a conjugate vaccine as the bacterial capsular polysaccharide material is linked to tetanus toxoid, diphtheria toxoid, a diphtheria-like protein, or a mix of proteins from other bacteria

    • All are effective in preventive Hib disease

WHO/V&B/AVI


Choosing the right vaccine12
Choosing the Right Vaccine

  • There are various formulations of Hib vaccine

    • Liquid Hib vaccine (monovalent)

    • Liquid Hib combined with DTP

    • Liquid Hib & Hepatitis B combined vaccines

    • Lyophilised (freeze-dried) Hib with saline diluent (monovalent)

    • Lyophilised Hib vaccine to be used with liquid DTP, DTP-HepB, DTP-IPV, DTaP, or DTaP/IPV in combination

WHO/V&B/AVI


Choosing the right vaccine13
Choosing the Right Vaccine

  • Is Hib vaccine recommended for all countries?

    • In industrialised countries of Europe and the Americas, Hib has been in use for almost a decade now

    • There is enough evidence that Hib disease is a major public health problem in the Americas, Sub-Saharan Africa and the Middle East

    • There is limited evidence to show that Hib disease is a public health problem in Asia & Eastern Europe

WHO/V&B/AVI


Choosing the right vaccine14
Choosing the Right Vaccine

  • Combination vaccines

    • DTP is the earliest combination vaccine in use

    • In the current Vaccine Fund supplies, combinations include DTP-HepB (tetravalent) or DTP-HepB+Hib (pentavalent),

    • In future, it is possible to have DTP-Hib or HepB-Hib

    • In the industrialised countries, there are many different combinations in use

WHO/V&B/AVI


Choosing the right vaccine15
Choosing the Right Vaccine

  • Why combine vaccines?

    • More & more vaccines becoming available. So if combined

      • fewer injections, less distress to infants & parents

      • less visits to health facility

      • less injection related complications

      • reduced costs (lower overall cost of vaccination programme)

      • may simplify transportation & storage problem

WHO/V&B/AVI


Challenges of combined vaccines
Challenges of combined vaccines

  • pharmaceutical

  • immunological

  • clinical

  • regulatory

  • manufacturing

  • public health

WHO/V&B/AVI


Any interference

antigens

adjuvants

preservatives

pH

contaminants

stabilizers

excipients

Any interference?

  • immunogenicity?

  • reactogenicity?

  • shelf-life?

  • stability?

  • manufacturing, supply?

WHO/V&B/AVI


Choosing the right vaccine16
Choosing the Right Vaccine

  • Which vaccine to choose?

    • For those countries introducing only HepB vaccine without a birth dose, the best choice is a combination of DTP-HepB

    • For those countries with a birth dose, they may either have monovalent HepB for birth dose and a combination DTP-HepB for the rest or may continue with only monovalent HepB and DTP separately

WHO/V&B/AVI


Choosing the right vaccine17
Choosing the Right Vaccine

  • Which vaccine to choose?

    • For those countries introducing both HepB and Hib vaccines, the most efficient choice is the pentavalent (DTP-HepB+Hib), if there is no birth dose for infants for HepB

    • If birth dose of HepB is necessary, then a combination of DTP-Hib and monovalent HepB may be an alternative choice

WHO/V&B/AVI


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