Vaccines

RationaleSuccessesProblems

Nester 5th edition Chapter 17th

Nester Chapter 17

• Principles of Immunization• Naturally acquired passive immunity• Naturally acquired active immunity• Artificially acquired passive immunity• Artificially acquired active immunity

Principles of Immunization• Antiserum

– Serum containing antibodies

• Antitoxin– Serum protects against toxin

• Immune globulin– Passive immunization preparations contain

gamma globulins IgG.

• Hyperimmune Globulins– Sra of donors with high amount of

antibodies

Nester Chapter 17• Herd Immunity - the inability of an

infectious disease to spread in a population because of the lack of a critical concentration of susceptible non-immune hosts.

• Vaccine - a preparation of attenuated or inactivated microorganisms or viruses or their components used to induce active specific immunity.

Herd Immunity Figure 2

InfectiousAgent

Active Immunization or Recovery from Natural Disease

Non-ImmuneNo disease

Non-ImmuneDisease

Vaccines• Attenuated vaccine agents

– Either organisms or viruses that cause a sub-clinical or mild disease and that produce long lasting immunity.

– Antigen is intact, may decrease circulation of wild type

– Examples- mumps, measles, rubella, yellow fever and Sabin polio

Nester Chapter 17• Inactivated vaccine agents

– Antigen is altered slightly to still produce immunity without the disease

– Whole agents• Killed micro-organism or inactivated virus• Example- cholera, influenza, rabies and

Salk vaccine

– Toxoid• Inactivated toxins• Example- Diphtheria and tetanus

Inactivated vs. Attenuated Virus Vaccines Table 1

Property Attenuated Inactivated

Route of Administration Injection, oral, or nasal Injection

Dose of Virus Low High

Number of Doses Single Multiple

Duration of Immunity Long-term Short-term

Antibody Immune Response IgG and IgA IgG

Cell-mediated Immune Response Good Poor

Heat Lability in Tropics Yes No

Reversion to Virulence Rarely, OPV No

Cost Low High

Nester Chapter 17

• Protein sub-unit vaccines– Key protein antigens or antigenic

fragments– Examples- acellular pertussis (aP)

• Recombinant vaccines – Subunit vaccine produced by

genetically engineered micoorganism– Example- Hepatitis B

Nester Chapter 17

• Polysaccharide vaccines– composed of the polysaccharide that

make up capsule– elicit a poor response

• Conjugate vaccine– improvement over purified– Haemophilus influenza type b and

Streptococcus pneumonia

Nester Chapter 17

• Adjuvant– Inactivated contain a substance that

enhances the immune response to antigens

– Currently approved in United States is alum (Aluminum hydroxide and aluminum phosphate)

Comparison of the Antibody Response to Inactivated and Attenuated Vaccines – Figure 1

Time in Days

Antibody

Levels

Serum IgG - Both

Serum IgM - Both

Nasal IgA m- Atten

Serum IgA - Both

Duodenal – IgA - Atten

Nasal & Duodenal IgA - Inactivated

Nester Chapter 17

• Text 17.1 Some important vaccines• Text 17.3 Effectiveness of vaccines

in US (20th Century)• Text 17.4 Recommended schedule

in the US (2000)• Text 17.5 Diseases for which new

vaccines are sought

Vaccines

• Rationale – To produce, without harm to the

recipient, a degree of resistance sufficient to prevent a clinical attack of the natural infection

• Goals– To increase Herd Immunity– To help limit a present epidemic– To prevent a future epidemic

Pertussis Death Rate/Million Citizens by Century – Figure 3

Penicillin

Vaccine

Identification

Vaccines

• Properties of an Ideal Vaccine– Promotes effective immunity– Confers lifelong protection– Has no side effects– Is stable– Is affordable in price not quality– Is seen to be good and effective

• No vaccine is perfect; some are close.

Prevention

• Phases of vaccine testing– Phase I

• testing for safety• ability to induce an immune response

– Phase II• determine optimum dose• kinds and duration of responses

– Phase III• effectiveness

Vaccines

• Duration of immunity varies:– For different vaccines.– For different groups of people.– Since protection does not always

relates to antibody level.

Vaccines• Contraindications - Do not give:

– Vaccines to someone with an acute disease or neurological disturbance.

– Attenuated vaccines to pregnant women.– Vaccines in the first trimester of pregnancy.– Vaccines to people on immunosuppressive

drugs or irradiation or with AIDS.– Vaccines made in eggs to people allergic to

eggs.

Vaccines

• Hazards– Mild to moderate pain at the injection

site– Fever and malaise for a day or two– Anaphylaxis - rare– Encephalopathy– Guillain-Barre syndrome– Epilepsy

Vaccines

• Hazards– Death from the vaccine viral strain– Aseptic meningitis– Demyelinating disease– Deafness– Sterility– Arthritis

Vaccines

• Safety considerations– Use a separate sterile syringe and

needle– Avoid errors - check the vial– Consider patient’s history– Consider contraindications– Keep careful records

Virus Vaccine Types

• MMR – measles, mumps, rubella• Polio• Chickenpox• Hepatitis A• Hepatitis B

Measles• Disease - Fig. 22.21

– 0-1000 cases/year - U.S.

– Death 1-2/1000 up to 150/1000 (15%)

– Secondary infections 85%

– Encephalitis 1/2000 1/2 die; 1/2 lose a function

– Pneumonia 1/20 -(5%)

• Vaccine– Encephalitis or

severe allergic reaction 1/1,000,000

– Thrombocytopenia purpura 3/100,000

– Aseptic meningitis 1/11,000 (mumps)

– Death is rare

Mumps

• Disease– 0-2 cases per 100,000 in

US– Hearing loss or deafness– Encephalitis– Pancreatitis– Aseptic meningitis 10%– ¼ cases in post-pubertal

males orchitis– 1 in 20 post-pubertal

females ovarian involvement pelvic pain

• Vaccine– Aseptic meningitis 2%

Rubella

• Disease– 0.1-0.2 cases per

100,000 in US– Congenital rubella

• Blind• Deaf• Retarded• Heart defects

• Vaccine– Arthralgia– Transient arthritis

2-3 weeks– Knee joint arthritis

may last 24 months

– Same as MMR

Polio

• Disease– 0 cases since

2000 from vaccine in US

– Cases come from outside US

– Paralytic death rate 1-2 %

• Vaccine– 8 cases/yr– 1 case/2,500,000

doses– Guillain-Barre

Chickenpox

• Disease– 10-60,000 cases

per year in US– 50-90 deaths– Zoster 77/100,000 – Encephalitis– Pneumonia

• Vaccine– Zoster 18/100,000

Hepatitis A

• Disease– 3-10 cases per

100,000 in US– Long

convalescence period of about a month

– 11% hospitalized

• Vaccine– Mild or of no

consequence– Same as placebo– Soreness and

redness at inoculation site

Hepatitis B

• Disease– 3-25 cases per

100,000 in US– Death 0.5-2%– Cirrhosis 4,000/yr.

• 25% die

– Cancer 800/yr.– 2-10% adult

carriers– Infants 90%

become carriers

• Vaccine– Autoimmune

disease• Lupus• Rheumatoid

arthritis

Bacterial Vaccine Types

• DPT– Diphtheria– Pertussis– Tetanus

• H. influenzae• Pneumococcal pneumonia

Diphtheria

• Disease– 0-5 cases a year

in US– Death 1/20– Heart– Kidney– Nervous system

• Vaccine– toxoid– Continuous crying

then full recovery 1/100

– Guillain-Barre– Brachial neuritis– Anaphylaxis

Pertussis

• Disease– 0.5-3.5 cases per

100,000 in US– Death 1/200– Encephalitis 1/20– Pneumonia 1/8

• Vaccine– Acute

encephalopathy 0-10 cases/1,000,000 immunizations

– Acellular vaccine has far fewer side effects especially of the neurological types

Tetanus

• Disease– 30-50 cases /yr. in

US (97% non-vaccinated)

– Mortality 30% in US

– Mortality 50% or more worldwide

• Vaccine– toxoid– Convulsions then

full recovery 1/1750

– Guillain-Barre– Brachial neuritis– Anaphylaxis

H. influenzae

• Disease– Age > 5:

0.5/100,000– Age < 5: 2/100,000– Death 3-7%

neurological disease– Pneumonia - death

50%– Epiglottitis– Septic arthritis

• Vaccine– Reduced

meningitis so much that S. pneumo has replaced H. influenzae

– Juvenile diabetes is a side effect

Pneumococcal pneumonia

• Disease– Death 5-20%

untreated– Resistance is a

problem• 1 state: >401

cases• 10: 101-400• 15 + 1: 1-100• 0: rest

• Vaccine

Health People 2010