This document provides an overview of vaccines and immunization. It defines immunization as the process of making a person immune or resistant to an infectious disease, typically through vaccine administration. The document discusses the history of vaccines, types of vaccines, immunization schedules, special populations, adverse reactions, and the importance of immunization in preventing disease outbreaks and saving lives. It concludes that vaccinations reduce global child mortality and allow individuals to live healthier lives while being economically sensible.

1. Vaccines
Dr. Destiny Stuart
Intern
Department of Pediatrics
April 21st 2020

2. Objectives
• Definition
• Epidemiology
• Mechanism of Action
• History
• Types of immunization
• Vaccines
– Cold Chain
• Types of vaccinations
• Immunization schedule
– Strategies
– Special populations
• Adverse reactions
– Complications

3. Immunization
• According to WHO, Immunization is:
• “The process whereby a person is made immune or resistant
to an infectious disease, typically by the administration of a
vaccine.”
– Is a proven tool for controlling and eliminating life-threatening infectious
diseases
– Prevents between 2 and 3 million deaths each year.
• Cost-effective
• Has defined target groups
• Can be delivered effectively
• No major lifestyle change required.

4. Epidemiology
• In The Bahamas, national immunization coverage for
childhood immunizations has remained greater than or at the
WHO target for the past decade. (MOH, 2017)
• Immunization coverage in 2015 was 95% for DPT/Hib/Hep B
and Polio and 94% for MMR.
• The recommended coverage by WHO is greater than 90% and
the Region of the Americas is greater than 95%.

5. Overview

8. History
01
02
03
04
05
06
18th and 19th century
In 1798, the first smallpox vaccine was
developed. Over the 18th and 19th centuries,
systematic implementation of mass smallpox
immunisation culminated in its global
eradication in 1979
1796
Edward Jenner inoculated a
13 year-old-boy with vaccinia
virus (cowpox), and
demonstrated immunity to
smallpox .
17th century
Buddhist monks drank snake
venom to confer immunity to
snake bite and variolation
(smearing of a skin tear with
cowpox to confer immunity
to smallpox)
1890 - 1950
•Bacterial vaccine development proliferated, including
the Bacillis-Calmette-Guerin (BCG) vaccination, which
is still in use today.
•Alexander Glenny perfected a method to inactivate
tetanus toxin with formaldehyde. The same method
was used to develop a vaccine against diphtheria in
1926. Pertussis vaccine development took
considerably longer, with a whole cell vaccine first
licensed for use in the US in 1948..
1897 and 1904
Louis Pasteur’s experiments
spearheaded the development of live
attenuated cholera vaccine and
inactivated anthrax vaccine in
humans
1950-1985
Viral tissue culture methods
developed from 1950-1985,
and led to the advent of the
Salk (inactivated) polio
vaccine and the Sabin (live
attenuated oral) polio
vaccine. Mass polio
immunisation has now
eradicated the disease from
many regions around the
world

9. Types of Immunization
• Passive immunization- delivery of preformed
antibodies, usually a Ig which may be a hyperimmune Ig
developed with high concentration against a specific disease
(e.g HBIg for Hep B).
• Useful in 3 settings:
– Host can’t make antibodies (1⁰ immunodef)
– Preventatively pre/post-exposure in a immunodeficient
child
– Treatment to soften the symptoms for a disease already
present (e.g Kawasaki disease and IVIG)

10. Types of Immunization
• Active immunization- all, part or a modified product
(toxoid, purified antigen) of a microorganism is given to host
to mount an immune response.
– Intact organisms may be inactivated (killed) or
live-attenuated (weakened) strains of the
organisms known to cause disease.
– Elicited immune response mimics the response to
natural infection with little to no risks

11. Cold Chain
• The process used to maintain optimal conditions during the transport,
storage, and handling of vaccine
– Starts at the manufacturer and ends with the administration of the vaccine to the client
• Optimum temperature for refrigerated vaccines is between
+2°C and +8°C (+35°F and +46°F).
– For frozen vaccines the optimum temperature is –15°C (+5°F) or lower.
In addition, protection from light is a necessary condition for some
vaccines
• Proper storage temperatures must be maintained at every
link in the chain or vaccine may be damaged and unsuitable
for administration.

13. Bahamas Cold Chain storage
In The Bahamas, vaccines are flown in from PAHO, transported to PHA
then, transported to various family islands in cargo containers via the
mailboat and other various brokers.
The vaccines are stored at our National Cold storage facility located at
Flamingo Gardens clinic.

14. Types of Vaccines
• There are many types of
vaccines, categorized by the
antigen used in their
preparation.
• Their formulations affect
how they are used, how they
are stored, and how they are
administered.
• The globally recommended
vaccines discussed in this
module fall into the four
main antigen types.

16. Immunologic Constituents
• Suspending fluids – sterile water,
saline
• Preservatives, Stabilizers,
Antibiotics
– used to inhibit or prevent
bacterial growth
– Stabilize the antigens or
antibodies
• albumin, phenols, neomycin,
mercurial
• Adjuvants – evoke suboptimal
immunologic response
– To enhance immunogenicity
• Al hydroxide, Al phosphate

17. Immune Response
• Immune response to one live virus vaccine
might be impaired if administered within 30
days of another live virus vaccine
• Only OPV and MMR can be administered at
anytime before, with or after each other

18. Immune Response
• Live virus vaccines can interfere with the
response to a tuberculin test
• Tuberculin testing can be done either on the
same day that live virus vaccines are
administered or 4 – 6 weeks later

20. Who should we immunize?
• When considering providing immunizations for
an individual, consider
– health status of the recipient
– the type of immunization to be given.
• Can they mount an appropriate immune
response?
– Benefits vs. risks

21. Immunization schedule
• The World Health Organization monitors vaccination
schedules across the world, noting what vaccines are included
in each country's program, the coverage rates achieved and
various auditing measures.
• WHO suggests the immunization schedule based on the
country, and what diseases are prevalent in that region
• Factors for developing the schedule include
– Host ability to respond (eg, lost maternal antibody)
– Need for multiple doses (eg, IPV)
– Minimal intervals needed between serial doses
– Available products (eg, combination vaccines)

22. Immunization Schedule for The Bahamas

23. Route of administration
The route of administration is the path by which the vaccine is introduced into the
body.
This is a critical factor for success of the immunization.
A substance must be transported from the site of entry to the part of the body where
its action is desired to take place.

24. Injection sites

25. Special Considerations
• Persons with hemophilia
– Increased risk of hepatitis B & hematomas
– Assess the patient’s bleeding risk
– Use fine needle & apply pressure to the site

26. Special considerations…
• Altered immunocompetence
– Killed or inactivated vaccines can be administered
to all immunocompromised patients
– OPV should not be given to any household
contacts of an immunocompromised patient
– IPV can be given

27. Special considerations….
• Altered immunocompetence
– MMR is not contraindicated to close contacts of
immunocompromised persons
– MMR vaccine is recommended for all
asymptomatic HIV-infected persons and should be
considered for all symptomatic HIV-infected
persons

28. Special considerations…
• Preterm infants
– Regardless of birth weight should be vaccinated at
the same chronological age and according to the
same schedule
– Use full recommended dose except BCG
– OPV should be deferred until discharge from the
nursery

29. Special considerations…
• Asplenic/SCD children
– Due to increased risk of infection by encapsulated
organisms, the 23 valent PSC Pneumoccocal is
recommended
– Every 3-5 years

30. Pneumococcal Vaccine
There are 2 types of pneumococcal vaccines PCV13 and PCV23
CDC recommends PCV13 for all infants as a series of 4 doses.
• Give 1 dose at 2 months, 4 months, 6 months, and 12 through 15 month
PCV23 is recommended every 3- 5 years in those with:
• functional or anatomic asplenia (e.g., splenectomy or congenital asplenia)
• sickle cell disease and other hemoglobinopathies
• congenital or acquired immunodeficiencies (e.g., B- (humoral) or T-
lymphocyte deficiency, complement deficiencies, and phagocytic disorders
• generalized malignancy
• HIV infection
• immunosuppression due to treatment with medication, including long-term
systemic corticosteroids, and radiation therapyn

31. Special considerations…
Pregnancy
Generally, vaccines that contain killed (inactivated) viruses can be given during
pregnancy
•Influenza
•Tetanus toxoid, reduced diphtheria toxoid and acellular pertussis (Tdap)
vaccine.
• One dose of Tdap vaccine each pregnancy for protection against pertussis.
• Ideally, the vaccine should be given between 27 and 36 weeks of pregnancy.
HBsAG Positive mother
• Administer HBIG (0.5 mL, IM) and single-antigen hepatitis B vaccine, 5 (0.5 mL, IM)
at separate injection sites within 12 hours of birth.
For newborns of HBsAg-negative mothers
•A Single-antigen hepatitis B vaccine (0.5 mL, IM) within 24 hours of birth, or at
hospital discharge, whichever comes first, to all newborns

32. Vaccination strategies
Cocoon strategy
• Cocooning aims to protect
newborn infants from
becoming infected
with pertussis by
administering DTaP/Tdap
(tetanus, diphtheria and
acellular pertussis) booster
vaccine to mothers, family
members and any individuals
who would come into regular
contact with the newborn
infant.
Ring vaccination
• Hinders the spread of a disease
by vaccinating only those who are
most likely to be infected
• When someone falls ill, adults
they might have infected
are vaccinated.
• Contacts who could have been
infected might include family,
neighbours, and friends.

33. …Like all things in life, vaccines are not perfect

34. Adverse Event Following Immunization (AEFI)
“A medical incident that takes place after an immunization,
causes concern, and is believed to be caused by
immunization”
• May occur because of
– Program error or
– Sensitivity to vaccine or it may occur coincidentally
• AEFIs must be taken seriously and the management must be rapid
and professional.
• Common, minor side effects, such as:
Mild fever, pain, swelling or redness at the site of the injection, and
irritability usually resolve without any serious consequences.

35. Types of AEFI:

36. COMMON, MINOR REACTIONS
Vaccine
Local reaction
(pain, swelling,
redness)
Fever > 38oC
Irritability, malaise &
non specific
symptoms
BCG Common -- --
Hib 5% - 15% 2% - 10% --
Hepatitis B
Adult up to 15%
Children up to 5%
1% - 6% --
Measles/MMR Up to 10% 5% - 15% Up to 5% (rash)
Polio (OPV) -- Less than 1% Less than 1% *
Tetanus/DT/Td Up to 10% ** Up to 10% Up to 25%
Pertussis
(DPT - whole cell) c Up to 50% Up to 50% Up to 60%
* Rate of local reactions likely to increase with booster doses, up to 50-85%
** Symptoms include diarrhoea, headache, and/or muscle pains

37. Minor reactions due to vaccination

38. Anaphylaxis due to vaccinations

39. How can AEFI be minimized?
• Use a separate site for each vaccine.
• Use auto-disable syringes for all immunization injections.
• Use new disposable syringe for each reconstitution.
• Always check the label for the name of vaccine/diluent, expiry date and
vaccine vial monitor.
• Shake the T series and Hep-B vaccine vials before drawing the dose.
• Reconstitute vaccines only with diluents supplied by the manufacturer
for that Vaccine
• Record the time of reconstitution of vaccine on the vial label.
• Use Measles and BCG vaccine within 4 hours of reconstitution.
• If they could not be used within stipulated time then discard the
reconstituted vials.

40. Importance of immunizations
• Vaccines can prevent outbreaks of
disease and save lives.
• When a critical portion of a
community is immunized most
members of the community are
protected against that disease
• Even those who are not eligible for
certain vaccines—such as infants,
pregnant women, or
immunocompromised
individuals—get some protection

41. Conclusion
•The benefits of vaccination extend beyond prevention
of specific diseases in individuals.
•Vaccination makes good economic sense, and meets
the need to care for the weakest members of
societies.
• Vaccinations reduce global child mortality and allows
every individual the opportunity to live a healthier life.

43. References
• Centers for Disease and Control and Prevention (CDC). Parents Guide to Childhood
Immunizations. http://www.cdc.gov/vaccines/pubs/parents-guide/default.htm.
Accessed July 1, 2015.
• CDC. Impact of Vaccines in the 20th &
21st Centuries. http://www.cdc.gov/vaccines/pubs/pinkbook/downloads/appendic
es/G/impact-of-vaccines.pdf. Accessed July 1, 2015.
• World Health Organization.
Poliomyelitis. http://www.who.int/mediacentre/factsheets/fs114/en. Accessed July
1, 2015.
• WHO [World Health Organization]. WHO Vaccine-Preventable Diseases: Monitoring
System, 2006 Global Summary. Geneva, Switzerland: World Health Organization;
2006.
• CDC. General recommendations on immunization: recommendations of the
Advisory Committee on Immunization Practices (ACIP). MMWR. 2011;60(2):R1-R64.
• https://www.bahamas.gov.bs/wps/portal/public/news%20and%20press%20releas
e/national%20immunization%20protocol/!