vaccines and vaccination mb2010 16jul2008

7/30/2019 Vaccines and Vaccination MB2010 16Jul2008

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Vaccines and Vaccination

Dr Alex DodooPhD, MPSGH, MRPharmSAg. Director, Centre for Tropical Clinical

Pharmacology & TherapeuticsUGMS, Accra


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Overview

Vaccine preventable diseases

Vaccines Available

Expanded Programme on Immunization

Schedule of Immunization for Ghana

Current Global Trends on Immunization

Global Advisory Committee on Vaccine

Safety


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Vaccine preventable diseases

The goal of a vaccine is to make a person immune toviruses or bacteria

Immune SystemBodys defences against virusesand bacteria

Antibodies

Lymphocytes (B-lymphocytes and T-lymphocytes andMemory Cells)

Immunity and immune memory

From natural infection

From vaccination


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Types of Vaccines

Type of Vaccine Examples

Killed, intact bacteria Typhoid vaccine

Killed, intact virus Inactivated polio vaccine, Hep A

virusKilled, disrupted virus Influenza vaccine

Live, weakened or attenuated

vaccine

Oral polio vaccine, MMR, Chicken

pox

Purified bacterial proteins Acellular pertusis vaccine

Purified bacterial polysaccharide Hib vaccine, Pneumococal vaccine

Purified viral protein Hep B vaccine

Inactivated bacterial toxin Diphtheria and tetanus toxoids


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E P I

Expanded Programme on Immunization

National Programme

Seeks to achieve maximum coverage forchildhood immunization

Part of the Ministry of Health and Ghana

Health ServiceImmunization free to all children in Ghana

National Immunization Schedule


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EPI/GHS/MOH

Disease/Vaccine Age For

Immunization

Tuberculosis (TB)Polio

BCG, OPV0

At Birth

Diphtheria, Pertussis (Whooping Cough), Tetanus,

Hepatitis B, Haemophilus influenzae type B

(HiB)PolioDPT1-Hep B1+Hib1 (Five in one)

OPV1

Six Weeks

Five in One 2

OPV 2

10 weeks


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EPI/GHS/MOH

Disease/Vaccine Age For

Immunization

Diphtheria, Pertussis (Whooping Cough), Tetanus,

Hepatitis B, Haemophilus influenzae type B

(HiB)PolioDPT3-Hep B3+Hib3 (Five in one)

OPV3

14 weeks

Measles, Yellow Fever 9 months


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Anti-immunisation lobby

IMMUNISATION SAFETY

IS AN EMERGING ISSUE

Regulations are changing

Vaccination campaign

Mishandling rumoursInternet

Evolution of programme

Unsafe injection

Inadequatemonitoring


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If we have no fear of vaccines, but

have fear of disease, we vaccinate our

children

If we have no fear of vaccines, but no

fear disease either, there is inertia

But if we have no fear of disease, but

fear of vaccines, we refuseimmunization

Source: LW Sullivan, President Morehouse School of Medicine, Georgia US.

At US National Immunization Conference, Atlanta, Georgia, July 1998


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Target diseases disappearing

Difficult to prepare for crisesNew communications: television and

Internet

Bad news more exciting than good news

Very technical subject with difficult concepts

to explain

A communicationschallenge


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Risk whendisease isvirtually

absent

Risk

during anepidemic

Concepts difficult even

for professionals e.g.

temporal vs.causal

association,relative risk,

risk assessment

A communicationschallenge


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Parents seek litigation

Is the service for the benefit of individual or

society?Compulsory or opt-out?

Mass campaigns vs. right to choose

Compensation

Legal aspects


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ADVERSE EVENTS

Anti-vaccine lobby reduced coveragewith pertussis vaccine

Number of cases and deaths rose for

some years afterwardsConclusion: misinformation hurts

immunization programmes and children

Does it matter?


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0

100

200

300

400

500

I

1940 1950 1970 1980 1990

Vaccine

uptake

DTP introduced

81%

31%

93%

Year

Active AVM

Source: Gangarosa. Lancet 351, 1998

1960

INCIDENCE OF PERTUSSIS IN COUNTRIES AFFECTED BY

ACTIVE ANTI-VACCINE MOVEMENTS (United Kingdom)

RISKS OF MEASLES INFECTION


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RISKS OF MEASLES INFECTION

VS. RISKS OF MEASLES VACCINE

Otitis 7-9% 0

Pneumonia 1-6% 0

Diarrhoea 6% 0Post-infectiousencephalomyelitis

0.5/1000 1/million

SSPE 1/100 000 0

Anaphylaxis 0 1/100 000 million

Thrombocytopenia Poorly quantified 1/30 000

Death 0.1-1/1000 (up to 5-15%) 0Duclos P, Brian J. Ward

Measles infection Measles vaccine


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RISK-BENEFIT OF VACCINES

The complications and accidentsmust be

looked upon as the price we pay for the

protection these agents confer upon us. Thereis no insurance without a premium. Our

business is to provide greater and more

comprehensive insurance and to diminish thesize of the premium

Wilson (1967) Wilson GS, The Hazards of immunisation,Athlone Press, London 1967


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Wait to draw vaccines into syringes until immediatelyprior to administration

Never mix vaccines in the same syringe unless they are

specifically approved for mixingRecord vaccine and administration information, including

lot numbers and injection sites, in the patient's record

If errors in vaccine storage and administration occur, take

corrective action immediately to prevent them fromhappening again and notify public health authorities


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Contraindication to vaccination

Many conditions are often inappropriately regarded as contraindications tovaccination. In most cases,the following arenot contraindications:

Mild acute illness (e.g., diarrhea and minor upper-respiratory tractillnesses, including otitis media) with or without low grade fever

Mild to moderate local reactions and/or low grade or moderate feverfollowing a prior dose of the vaccine

Current antimicrobial therapy

Convalescent phase of illness

Recent exposure to an infectious disease

Premature birth

Breastfeeding


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?

Children with compromised immune system, asoccurs with cancer patients

A person has had a severe allergic reaction to a

vaccine

A person with a mild, common illness, such as a coldwith a low-grade fever, does not have to wait to bevaccinated.

Follow any guidelines given by the EPI especially incases of infections including HIV/AIDS


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The providers of vaccines can do a number of things to helpmake vaccines as safe and effective as possible

providing patients or parents/guardians with informationabout vaccines and immunization is very important.

Before administeringeach dose of certain vaccines,provide sufficient information to either the adult vaccineeor to the childs parent/legal guardian in a language theycan understand

discuss the benefits and risks associated with specific

vaccines and what to do and who to contact in case ofadverse events


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Most people experience no side effects, or only mild ones,following immunization.

Mild side effects may include soreness, swelling, or redness at

the injection site or mild fever. Severe side effects, such as severe allergic reactions,

following vaccination are extremely rare.

However, any provider who administers vaccines should haveprocedures in place for the emergency care of a person who

experiences an anaphylactic reaction.


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What to do in case of adverse events

Manage appropriately as per hospital or

institutional guidelines/protocols

Fill an Adverse Events FollowingImmunization (AEFI) form

Send form to EPI or to National Centre for

Pharmacovigilance, Food and Drugs Board


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Adjuvants and Safety

Complex, evolving and neglectedsafety area

Review of current, new & novel adjuvants

GACVS: WHO role in facilitating dialoguescientists-academe/industry and regulators

Need consistent regulatory approach

(Tech Report Series)

Need for collation A/Es with adjuvants

WHO


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Adjuvants contd

Need for short and long-term safety data for

adjuvants, including effect on immune

system

Need for validated animal models for

adjuvant safety testing

Need to evaluate adjuvant safety both alone

and combined with antigen(s)

Need for pharmacokinetics of antigens with

with adjuvants WER 2004;79:269-272


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Way Forward:GACVS

A/E vaccine allegations ongoing need for more

reviewsMore consultation with industry,national govts

and drug regulators

Conclusions by GACVS open for scrutiny

GACVS work with and give more support to drugregulatory authorities and to WHOImmunizations, Vaccines and Biologicals

Folb et al American Journal of Public Health.2004; 94: 1926-31.

WHO


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WHO IVB, GACVS and National Govt

Bringing serious safety issues from nationalperspective to attention of WHO IVB important forshaping selection of topics for GACVS review

GACVS welcomes opportunities to share outcomesfrom reviews more widely

IVB and GACVS : Vaccine Safety Net Projecteffort made to assess systematically quality of

vaccine safety websites WER 2005;80: 3-7(http://www.who.int/vaccine_safety/en/)

IVB, GAVCS welcome opportunity for morecollaborative work on serious vaccine safety issues

vaccines and vaccination mb2010 16jul2008

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