National Immunization

Programme in Sri Lanka

Ruwandi De Silva
• 9 provinces & 26 districts
• Population 21,323,733 (2019)
• Life expec. at birth (75.3y)
- Male 72.1y
- Female 78.5y
• IMR-8/1000 live births (2018)
• <5Y mortality- 9/1000 live
births (2018)
 Vaccine
• Comes from Latin word “vaccinus” which
means “pertaining to cows”
• The first vaccine was based on the
relatively mild cowpox virus, which infected
cows as well as people
History of Immunization &
Vaccination
Edward Jenner
(1749-1823)
• English physician &
scientist
• The pioneer of the world's
first vaccine -smallpox
vaccine (1796)
 History of Immunization &
Vaccination
• Edward Jenner, a country physician practicing in
England, noticed that milkmaids rarely suffered from
smallpox & often got cowpox. They never became
ill with smallpox.
• In an experiment that laid the foundation for modern
vaccines,
• Jenner took a few drops of fluid from a skin sore of a
woman who had cowpox & injected the fluid into the
arm of a healthy young boy who had never had
cowpox or smallpox.
• Six weeks later, Jenner injected the boy with fluid from
a smallpox sore, but the boy remained free of
smallpox.
Vaccination
 Vaccination
• Vaccination is the administration of a vaccine
to stimulate a protective immune response
that will prevent disease in the vaccinated
person if contact with the corresponding
infectious agent occurs subsequently
• If the action is successful, it results in
immunization
vaccinated person has been immunized
• All vaccines produce antibodies which can
neutralize extra cellular pathogens
• Live viral vaccines evoke response against
intracellular pathogens ex. Measles vaccine
 Vaccination
• Vaccines are highly regulated, complex biologic
products designed to induce a protective
immune response both effectively and safely.
• One of the most important preventive health
care interventions
• One of the most cost-effective health
investments
• Today, there are many vaccines available to
prevent nearly 30 communicable diseases
 Immunization
• Immunization aims to induce immunity
against a disease
• Immunization is the process whereby a
person is made immune or resistant to an
infection, typically by the administration of a
vaccine
• Immunization is a proven tool for controlling
and eliminating and eradicating life
threatening infectious diseases
 Immunity
• The ability of the human body to tolerate
the presence of material indigenous to the
body (“self”), and to eliminate foreign
(“non-self”) material
• This ability provides protection from
infectious disease, since most microbes
are identified as foreign by the immune
system
• Immune system is classified into the
innate immune system & the
specific/acquired immune system
 Immunity Cont….
• Innate Imm. System consists of cells
-monocytes, macrophages, dendritic cells,
neutrophils, eosinophils & natural killer cells
• Innate imm. System identifies pathogens &
activates the specific/acquired imm. system
• Acquired Imm. System is composed of
lymphocytes to produce antibodies &
inflammatory cytokines
• Immunity to a microbe (antigen) is usually
indicated by the presence of antibody to that
organism
• Immunity is generally very specific to a single
organism or group of closely related organisms
• There are two basic mechanisms for acquiring
immunity - active and passive
 Active Immunity
• stimulation of the immune system to
produce antigen-specific humoral
(antibody) and cellular immunity
• usually lasts for many years, often for a
lifetime
• Two ways to acquire active immunity
1. Through the survival after an infection
with the disease-causing form of the
organism. Ex….
• After the exposure of the immune system
to an antigen, certain cells (memory B
cells) continue to circulate in the blood
(and also reside in the bone marrow) for
many years. Upon re-exposure to the
same antigen, these memory cells begin
to replicate and produce antibody very
rapidly to re-establish protection
2. Active immunity is by vaccination
• Vaccines interact with the immune system and
often produce an immune response similar to
that produced by the natural infection
• but they do not subject the recipient to the
disease and its potential complications.
• Many vaccines also produce immunologic
memory similar to that acquired by having the
natural disease
 Passive Immunity
• The transfer of antibody produced by one human
or other animal to another
• Passive immunity provides a temporary protection
against some infections Bcz the antibodies will
degrade over the time.
Ex. most common form of passive immunity is
that which an infant receives from the mother.
Antibodies are transported across the placenta
during the last 1–2 months of pregnancy.
As a result, a full-term infant will have the
same antibodies as its mother.
These antibodies will protect the infant from
certain diseases for up to one year.
This type of protection is better against some
diseases
Ex. measles,rubella & tetanus
 Factors may influence the
immune response to vaccination

• the presence of maternal antibody

• nature (live/non live) of antigen
• dose of antigen
• route of administration
• the presence of an adjuvant (e.g. aluminum/
oil containing material) added to improve the
immunogenicity of the vaccine
• Host factors such as age, nutritional factors,
genetics & coexisting disease
 Development of Immunization
Programmes in Sri Lanka
• 1886: Vaccination
Ordinance : Compulsory
vaccination for Smallpox –
Date of commencement - 1st
July 1887
• 1949 – BCG vaccine
• 1961 – Introduction of
“Triple” vaccine/DPT
(Diphtheria, Whooping
Cough/Pertussis, Tetanus)
• 1962 – Oral polio vaccine
 Development of Immunization
Programmes in Sri Lanka
• Responsible authority is Epidemiology Unit, MOH
• The Expanded Programme on Immunization (EPI)
established in 1978
• 1984- Measles vaccine
• 1996-Rubella vaccine
After 2000
• 2001 - MR vaccine
• 2003 - Hepatitis B vaccine
• 2008 - Hib (Haemophilus influenzae type B)
containing Pentavalent vaccine (DPT, Hep B &
Hib)
• 2009 - Live JE vaccine
• 2011 -MMR vaccine
• 2017 -HPV vaccine
 Reduction of vaccine
preventable diseases over time
 Direct achievements of National
immunization programme
• Last case of Smallpox in Sri Lanka 1972 Globally
Eradicated in 1979
• Last case of Diphtheria in 1991: almost eliminated
• Last case of Poliomyelitis in 1993 Regional Polio
free certification 2014 and Global Eradication plan
for 2016
• Congenital Rubella Syndrome: Near elimination
stage
• Neonatal Tetanus last case in 2009 and
eliminated
• South East Asia declared Maternal and neonatal
tetanus elimination in 2016
National Immunization Policy in SL-
2014
• To have a country free of vaccine preventable
diseases
• To ensure the availability and affordability of quality
immunization services
• To ensures the rational and evidence based
introduction of new vaccines
• To ensure proper implementation by monitoring,
evaluation, information management and operational
research of immunization
• To ensure financial sustainability of the National
Immunization Programme
• To ensure advocacy, promotion, awareness, protection
and support for the Immunization Programmme
• To implement the national immunization policy in a
systematic manner inclusive of all stakeholders
 Classification of vaccines
• Live attenuated
• Inactivated
 Live attenuated Vaccines
• Live vaccines are derived from “wild,” or
disease-causing, virus or bacteria. These
• wild viruses or bacteria are attenuated, or
weakened, in a laboratory, usually by
repeated culturing. The resulting vaccine
organism retains the ability to replicate (grow)
in the vaccinated person and produce
immunity, but usually does not cause illness.
• The immune response to a live attenuated
vaccine is virtually identical to that produced
by a natural infection.
 Live attenuated Vaccines
• Immunity following live vaccines is long-lasting,
and booster doses are not necessary, with the
exception of oral polio vaccine, which requires
multiple doses.
• For live vaccines, the first dose usually provides
protection
• The second dose is given to assure that nearly
100% of persons are immune
• Currently available live attenuated viral vaccines
include measles, mumps, rubella, varicella, yellow
fever, oral polio and influenza (intranasal).
• Live attenuated bacterial vaccines include BCG
and oral typhoid vaccine
 Inactivated vaccines
• produced by growing viruses or bacteria in
culture media and then inactivating them with
heat or chemicals (usually formalin)
• not alive
• they cannot grow in a vaccinated individual
and therefore cannot cause the disease
(even in an immunodeficient person)
• inactivated antigens are usually not affected
by circulating antibody
• they are non-infectious but retain the ability
to stimulate the immune system
 Inactivated vaccines
1. Whole cell vaccines
• Growing whole bacteria or viruses (e. g.
inactivated influenza or inactivated polio
vaccine) in culture media, then treating
them with heat and/or chemicals,
produces an inactivated, non-viable
vaccine
 Inactivated vaccines
2. Toxoid vaccines
• In some bacterial infections (e.g. diphtheria,
tetanus) the clinical manifestations of disease
are caused not by the bacteria themselves but
by the toxins they secrete.
• Toxoid vaccines are produced by purifying the
toxin and altering it chemically
• While no longer toxic, the toxoid is still capable
of inducing a specific immune response
protective against the effects of the toxin
 Inactivated vaccines
3. Subunit vaccines
• The whole organism is grown in culture
media and then the organism is further
treated to purify only those components to
be included in the vaccine
e.g. acellular pertussis and the
meningococcal B vaccine)
 Inactivated vaccines

4. Recombinant vaccines
Example- Hepatitis B vaccine is made by
inserting a segment of the hepatitis B virus
gene into a yeast cell.
• The recombinant hepatitis B vaccine is
identical to the natural hepatitis B surface
antigen, but does not contain virus DNA
• Therefore unable to produce infection
 Inactivated vaccines
5. Conjugated vaccines
• Children under two years of age do not
respond well to antigens such as
polysaccharides, which produce antibodies
via a T-cell independent mechanism
• If these polysaccharide antigens are
chemically linked (conjugated) to a protein
that T-cells recognize
• these conjugate vaccines can elicit strong
immune responses & immune memory in
young children
• Ex. Hib, HPV
• BCG- TB-Mycobaterium tuberculosis
• OPV- Poliomyelitis – Polio virus
• DTP- Diphtheria- Corynebacterium diphtheriae
-Tetanus- Clostiridium tetani
-Pertussis – Bordetella pertusis
• Hep B – Heapatitis B virus
• Hib –Bacterial meningitis - Haemophilus
influenzae type B
• MMR- Measles- RNA virus
- Mumps- RNA virus of Paramyxoviridae
family
- Rubella- Toga virus
• JE-Japanese encephalitis – Flavi virus
 AEFI Form
Adverse Effect Following Immunization
AEFI Surveillance System in Sri
Lanka
• SLMA Guidelines & Information on Vaccines
2017
• https://slma.lk/wpcontent/uploads/2017/12/
GSK-SLMA-Guidelines-Information-on-
Vaccines.pdf