Expanded Program on Immunization (EPI) Overview

• Launched by WHO in 1974

• Expansion Goals:

o Introduction of additional disease antigens into the vaccination schedule.

o Increase in the number of targets to be covered, including children and women.

EPI in 1974:

• At the time of its launch, less than 5% of children were immunized globally.
-

• Six target diseases:

-
1. Pertussis
~
2. Diphtheria

3. Measles -

4. Polio ~

5. Tetanus -
~
6. Smallpox

EPI Vaccines

1. BCG (Bacille Calmette-Guérin)

o Type: Live freeze-dried vaccine (must be reconstituted before use).

o Administration: Intra-dermal injection using a special needle and syringe.

o Dosage: 0.05 ml injected into the left deltoid region.

o If given correctly, the injection raises a small "bleb" which looks like the peel of
an orange.

o Effectiveness:

▪ 50%-80% effective against childhood tuberculosis (TB).

▪ Offers some protection against leprosy.

▪ Effectiveness in preventing adult forms of TB is uncertain.

o Booster dose isn’t recommended by the WHO

2. Triple Vaccine (DTP - Diphtheria, Tetanus, and Pertussis)

o Type: Liquid vaccine (must not be frozen).

 o Administration: Intramuscularly in the antero-lateral right thigh or upper arm.

o Dosage: 0.5 ml per dose.

o Schedule: Three doses are needed for full protection, at least four weeks apart
(typically administered at 2, 4, and 6 months).

o Variations:

▪ DT (with full diphtheria component)

▪ TT (tetanus toxoid alone) for women of childbearing age

▪ Td (reduced diphtheria component) for adults

▪ Some countries use acellular pertussis vaccine (aP) instead of whole-

cell pertussis.

3. Oral Polio Vaccine (OPV)

o Type: Liquid vaccine consisting of three serotypes of live attenuated poliovirus.

o Administration: Oral (2 drops), 3 doses.

o Vaccine Vial Monitors (VVMs): Since 1996, vials of OPV come with VVMs,
ensuring the vaccine’s safety by indicating if it has been damaged by heat.

o Once opened, vials of OPV can be stored and reused - provided they are kept
within the cold chain and not used beyond the expiry date.

o Additional Information:

▪ OPV is preferred for poliomyelitis eradication because it is cheaper (IPV

costs five times as much), easier to administer, and induces immunity in
the gut, where poliovirus multiplies and is shed in feces (can be shedded
in feces for 6 weeks).

▪ OPV is the vaccine of choice for polio eradication because it prevents

the spread of wild poliovirus, unlike IPV.

4. Injectable Polio Vaccine (IPV)

o Type: Inactivated vaccine that provides individual protection against polio

paralysis but does not prevent the spread of wild poliovirus, as it induces only
low immunity in the gut.

o Note: IPV cannot be used to eradicate polio, unlike OPV.

5. Measles (Measles is a highly infectious vaccine preventable disease ) Vaccine

o Type: Live attenuated freeze-dried vaccine.

o Administration: Subcutaneously, at the right arm.

o Dosage: 0.5 ml.

 o Storage: Must be protected from light and kept cool once reconstituted.

o Important: Any leftover doses from an opened vial must be discarded.

6. MMR Vaccine (Measles, Mumps, Rubella)

o Type: Combination of live attenuated viruses for measles, mumps, and rubella.

o Administration: Subcutaneously at the right arm.

o Dosage: 0.5 ml.

o Schedule:

▪ First dose given at 12 months.

▪ Second dose offered at preschool age (if not administered earlier).

▪ Effectiveness: Almost 100% protection after two doses.

7. Hepatitis B Vaccine

o Type: Liquid vaccine.

o Schedule:

▪ Three doses at 0, 1, and 6 months (at least four weeks apart).

▪ Dose: 0.5 ml administered intramuscularly.

o Storage: Must not be frozen.

o Note: The vaccine can be given at the same time as DTP.

o Types:

▪ Plasma-derived inactivated vaccine (since 1981).

▪ DNA recombinant (genetically engineered) vaccine (since 1986).

o Hepatitis B vaccine is the first vaccine to be developed against a form of cancer

(liver cancer).

o More than 2 billion people alive today have at some time in their lives been
infected with hepatitis B virus (HBV).

o Of these, about 350 million remain chronically infected carriers - a ticking time
bomb that can transmit the disease for many years before going on to develop
cirrhosis of the liver or liver cancer.

o Every year there are about 4 million acute clinical cases of hepatitis B and about
a million deaths.

o Primary liver cancer caused by hepatitis B is now one of the principal causes of
cancer death in many parts of Africa, Asia, and the Pacific Basin.
 8. Vitamin A Deficiency and Supplementation

o Role in EPI:

▪ Vitamin A can be given to mothers immediately after birth to enrich

breast milk.

▪ It is also given during routine immunizations or in campaigns, and as

treatment for measles cases.

o Dosage:

▪ Two doses of 100,000 IU of vitamin A at 9 and 18 months of age.

o Purpose:

▪ Combined with measles vaccination to boost immune function and

reduce mortality.

o By combining vitamin A with measles vaccine, WHO aims to benefit children in

two ways:

▪ By offering two interventions instead of one: the service is more

efficient, is seen to be more attractive, and vaccine coverage rises - thus
further reducing the incidence of measles.

▪ By raising the vitamin A status of high risk infants: not only does the
measles case fatality rate fall, but there is a reduction in overall
mortality

EPI Immunization Schedule (WHO Recommendations)

• Hepatitis B (HepB):

o For infants with HBsAg-negative mothers: 3 doses at 0, 1, and 6 months.

o For infants with HBsAg-positive mothers: Hepatitis B immune globulin (HBIG)

and vaccine within 12 hours of birth, followed by vaccine at 1-2 months and 6
months.

Notes:

• Simultaneous Vaccine Administration:

o All EPI vaccines are safe and effective when given at the same time but at
different injection sites.

• Vaccine Dose Interval:

o Doses given less than 4 weeks apart may reduce antibody response.

o These doses should not be counted as part of the primary series.

 • Lengthening the Interval:

o Longer intervals between doses lead to higher antibody levels.

o Complete the primary series early to avoid high-risk infection.

• Live Attenuated Vaccines:

o Provide long-lasting immunity with a single dose (e.g., measles vaccine).

o A second dose (e.g., MMR) ensures 100% protection.

• Inactivated/Killed Vaccines:

o Protection develops after 2nd or 3rd dose.

o Periodic boosting is needed for ongoing immunity.

• HIV Infection and Live Vaccines:

o Live vaccines should be avoided in children with HIV.

o Exception: Measles vaccine must be given to children with HIV as early as 6

months.

Vaccine Contraindications

Absolute Contraindications:

1. Anaphylaxis following ingestion of eggs (e.g., yellow fever and influenza vaccines).

2. Pertussis vaccine is contraindicated if the child has had:

o Fever of 40.5°C not caused by other conditions within 48 hours of vaccination.

o Collapse or shock.

o Convulsions, with or without fever, within 3 hours of vaccination.

3. HIV infection: Live attenuated vaccines are contraindicated, However, routine

vaccination with measles vaccine is a must as early as possible (6 month of age), in
addition to the scheduled dose at nine months).

Temporary Contraindications:

1. Pregnancy:

o The only vaccine that can be administered during pregnancy is Tetanus Toxoid
(TT).

2. Severe illness that requires hospitalization.

3. Immunosuppression:
 o Live attenuated vaccines should be avoided if a person is undergoing
immunosuppressant therapy or has conditions such as leukemia, lymphoma, or
cancer.

4. Recent receipt of blood:

o As it contains antibodies that neutralize the vaccine antigens

o Vaccination should be postponed 14-21 days after receiving blood.

Vaccine Delivery Strategies

1. Static Immunization Strategy:

o Immunization services are provided through PHC centers, hospitals, and

vaccine-qualified clinics.

2. National Immunization Days (NIDs):

o Mass immunization of all eligible children in a specific age group within a large
geographic area, typically over 1-3 days (e.g., two doses of polio vaccine).

3. Outreach Immunization Service:

o Health teams identify high-risk areas to vaccinate children at their homes.

False Contraindications to Immunization

1. Minor illnesses e.g. URT or diarrhea with low fever

2. Allergy e.g. asthma, hay fever, …etc.
3. Premature or small for date infants
4. Malnutrition
5. Child being breast fed
6. Family history of convulsions
7. Treatment with antibiotics
8. Dermatosis, or localized skin lesion
9. Chronic disease of the heart, lungs, kidneys or liver
10. Stable neurological condition e.g. Down’s syndrome
11. History of Jaundice at birth