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Shingles

Human Papillomavirus (HPV)

 HPV is the most common sexually transmitted disease

 Most people who are infected do not have any symptoms

 Pap tests are performed on females to evaluate cells from the cervix under a microscope

- Cells are examined for abnormal changes that if left untreated may develop into

cervical cancer.

Influenza

Figure(2-99)This woman has a skin rash from shingles.

Figure(2-100) This photo shows how influenza germs spread through the air when

someone coughs.

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Measles (Figure 2-101)

Mumps (Figure 2-102)

Figure (2-101)Head and shoulders of a boy with measles

Figure(2-102) This child is very swollen under the jaw and in the cheeks due to mumps.

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Rubella(Figure 2-104)

Rotavirus

 Causes severe vomiting and diarrhea that can lead to dehydration.

 Dehydration can lead to death particularly in countries where medical care is not readily

accessible.

 Before there was a vaccine virtually all children had this infection by the age of five.

Chickenpox (Figure 2-105)

Purpose of Vaccination

1. Protect the individual from disease.

2. Reduce the severity of disease.

Figure (2-104) This child was born with cataracts caused by a rubella infection his mother

.transmitted to him before birth

Figure (2-105) Illustrated A- Patient with chickenpox infection B- One of the chickenpox lesions became infected leading to

complications.

A B

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3. Protect the community.

4. Eradication of the disease.

History of vaccine development (Table 2-7)

In1796 Adward Jenner, used matter from cowpox pustules to inoculate patients successfully against

smallpox, which is caused by a related virus.

By 1900, there were two human virus vaccines, against smallpox and rabies, and three bacterial

vaccines against typhoid, cholera, and plague.

During the 20th century, other vaccines that protect against once commonly fatal infections such as

pertussis, diphtheria, tetanus, polio, measles, rubella, and several other communicable diseases were

developed. The initial EPI goals were to ensure that every child received protection against six

childhood diseases (i.e. tuberculosis, polio, diphtheria, pertussis, tetanus and measles) by the time

they were one year of age and to give tetanus toxoid vaccinations

to women to protect them and their newborns against tetanus.

Since then, new vaccines have become available. Some of them, such as hepatitis B, rotavirus,

Haemophilus

influenzae type b (Hib) and pneumococcal vaccines, are recommended by the WHO for global use.

Others, such as yellow fever vaccine, are recommended in countries where disease burden data

indicate they should be used.

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Regulatory and safety issues of vaccines before and after licenses

How the immune system works

How the immune system works ?

The pathogens causing the vaccine-preventable are mainly microorganisms such as bacteria or

viruses.

 Bacteria are single-celled life-forms that can reproduce quickly on their own.

 Viruses, on the other hand, cannot reproduce on their own. They are ultramicroscopic

infectious agents that replicate themselves only within cells of living hosts.

1798 Smallpox

18 85 Cholera

18 85 Rabies

1891 Anthrax

1896 Typhoid

1897 Plague

1923 Diphtheria

1923 Tuberculosis

1924 Tetanus

1926 Pertussi s

1927 Tetanus

1935 Yel low fever

1943 Typhus

1955 Polio (IPV)

1962 Polio (OPV)

1963 Measles

1967 Mumps

1969 Meningitis A

1970 Rubella

1972 Haemophilus

influenzae

1976 Viral influenza

1976 Pneumococcal

polysacchari de

1977 Meningitis C

(polysaccharide)

1981 Hepatitis B

1986 Meningitis B

1989 Hepatitis A

1995 Varicella zoster

1998 Rotavirus

1999 Meningitis C

(conjugate)

2000 Pneumococcal

conjugate

2006 Hum an

papilloma

virus

1800–1899 1900–1949 1950–1979 1980–1999 2000

Table (2-7) History of vaccine development

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Types of vaccine

Figure(2-106) Primary and secondary immune responses to the same pathogen

Live attenuated (LAV)

– Tuberculosis (BCG)

– Oral polio vaccine (OPV)

– Measles

– Rotavirus

– Yellow fever

Inactivated (killed antigen)

– Whole-cell pertussis (wP)

– Inactivated polio virus (IPV)

Subunit (purified antigen)

– Acellular pertussis (aP),

– Haemophilus infuenzae type b (Hib),

– Pneumococcal (PCV-7, PCV-10, PCV-13)

– Hepatitis B (HepB)

Toxoid (inactivated toxins)

– Tetanus toxoid (TT),

– Diphteria toxoid

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Mono and polyvalent vaccines

Vaccines may be monovalent or polyvalent. A monovalent vaccine contains a single strain of a single

antigen (e.g. Measles vaccine), whereas a polyvalent vaccine contains two or more strains/serotypes

of the same antigen (e.g. OPV).

Combination vaccines

Some of the antigens above can be combined in a single injection that can prevent different diseases

or that protect against multiple strains of infectious agents causing the same disease (e.g.

combination vaccine DPT combining diphtheria, pertussis and tetanus antigens). Combination

vaccines can be useful to overcome logistic constraints of multiple injections, and accommodate for a

children’s fear of needles and pain.

Live attenuated vaccines

Available since the 1950s, live attenuated vaccines (LAV) are derived from disease- causing

pathogens (virus or bacteria) that have been weakened under laboratory conditions. They will grow

in a vaccinated individual, but because they are weak, they will Live microorganisms provide

continual antigenic stimulation giving sufficient time for memory cell production. cause no or very

mild disease.

Attenuated pathogens have the very rare potential to revert to a pathogenic form and cause disease

in vaccinees or their contacts. Examples for this are the very rare, serious adverse events of: vaccineassociated paralytic poliomyelitis (VAPP) and

disease-causing vaccine-derived poliovirus (VDPV) associated with oral polio vaccine (OPV).

Sustained infection, for example tuberculosis (BCG) vaccination can result in local lymphadenitis or a

disseminated infection.

 If the vaccine is grown in a contaminated tissue culture it can be contaminated by other

viruses (e.g. retro viruses with measles vaccine).

Many LAVs require strict attention to the cold chain for the vaccine to be are subject to program

failure when this is not adhered to.

Protein-based subunit vaccines

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- Protein based subunit vaccines present an antigen to the immune system without viral

particles, using a specific, isolated protein of the pathogen .

- Commonly used protein-based subunit vaccines are the following:

- Acellular pertussis (aP) vaccines contain inactivated pertussis toxin (protein) and may

contain one or more other bacterial components. The pertussis toxin is detoxified either by

treatment with a chemical or by using molecular genetic techniques.

- Hepatitis B vaccines are composed of the hepatitis B virus surface antigen (HBsAg), a

protein produced by hepatitis B virus. Earlier vaccine products were produced using

purified plasma of infected individuals. This production method has been replaced by

recombinant technology that can produce HBsAg without requiring human plasma

increasing the safety of the vaccine by excluding the risk from potential contamination of

human plasma.

Polysaccharide vaccines

Some bacteria when infecting humans are often protected by a polysaccharide (sugar) capsule that

helps the organism evade the human defense systems especially in infants and young children.

Polysaccharide vaccines create a response against the molecules in the pathogen’s capsule. These

molecules are small, and often not very immunogenic. As a consequence they tend to:

Not be effective in infants and young children (under 18–24 months),

Induce only short-term immunity (slow immune response, slow rise of antibody levels, no immune

memory).

Examples of polysaccharide vaccines include Meningococcal disease caused by Neisseria

meningitides groups A, C, W135 and Y, as well as Pneumococcal disease.

Conjugate subunit vaccines

Conjugate subunit vaccines also create a response against the molecules in the pathogen’s capsule. In

comparison to plain polysaccharide vaccines, they benefit from a technology that binds the

polysaccharide to a carrier protein that can induce a long-term protective response even in infants.

Various protein carriers are used for conjugation, including diphtheria and tetanus toxoid. Conjugate

subunit vaccines, can therefore prevent common bacterial infections for which plain polysaccharide

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