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Vaccines: An Essential Tool for Public Health
- 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/!
Editor's Notes
- Vaccines stimulate the body’s own immune system to protect the person against subsequent infection or disease, IT IS A biological preparation that provides active acquired immunity to a particular disease Cost-effective health investments, with proven strategies that make it accessible to even the most hard-to-reach and vulnerable populations through outreach activities; and vaccination does not require any major lifestyle change.
- Adaptive immunity is triggered in vertebrates when a pathogen evades the innate immune system and (1) generates a threshold level of antigen and (2) generates "stranger" or "danger" signals activating dendritic cells.[2] The major functions of the adaptive immune system include: Recognition of specific "non-self" antigens in the presence of "self", during the process of antigen presentation. Generation of responses that are tailored to maximally eliminate specific pathogens or pathogen-infected cells. Development of immunological memory, in which pathogens are "remembered" through memory B cells and memory T cells. Therefore, by exposing an animal to an immunogen in a controlled way, its body can learn to protect itself: this is called active immunization. The most important elements of
- © Copyright PresentationGo.com – http://www.immune.org.nz/brief-history-vaccination
- Passive immunization occurs physiologically, when antibodies are transferred from mother to fetus during pregnancy, to protect the fetus before and shortly after birth.
- Active immunization can occur naturally when a person comes in contact with, for example, a microbe. The immune system will eventually create antibodies and other defenses against the microbe. The next time, the immune response against this microbe can be very efficient; this is the case in many of the childhood infections that a person only contracts once, but then is immune.
- The risks and benefits of using the vaccine in the specific host should be weighed carefully. Vaccines are intended for a host who is capable of mounting an appropriate immune response, who will likely benefit from the protection provided and ideally incur little or no risks. Live attenuated vaccines is contraindicated in: Pregnant woman Immunocompromised person – leukemia, lymphoma, malignancy, therapy with steroids, alkylating agents, antimetabolites Radiotherapy
- Hep B given at birth to babies of mother of unknown status
- Key point Manufacturers usually recommend the route of administration that limits best adverse reactions of the respective vaccine. Intramuscular (IM) injection administers the vaccine into the muscle mass. Vaccines containing adjuvants should be injected IM to reduce adverse local effects. Subcutaneous (SC) injection administers the vaccine into the subcutaneous layer above the muscle and below the skin. ntradermal (ID) injection administers the vaccine in the topmost layer of the skin. BCG is the only vaccine with this route of administration. Intradermal injection of BCG vaccine reduces the risk of neurovascular injury. Health workers say that BCG is the most difficult vaccine to administer due to the small size of newborns' arms. A short narrow needle (15 mm, 26 gauge) is needed for BCG vaccine. All other vaccines are given with a longer, wider needle (commonly 25 mm, 23 gauge), either SC or IM. Oral administration of vaccine makes immunization easier by eliminating the need for a needle and syringe
- OPV strains also produce a local immune response in the lining ('mucous membrane') of the intestines - the primary site for poliovirus multiplication. The antibodies produced there inhibit the multiplication of subsequent infections of 'wild' (naturally occurring) virus. This intestinal immune response to OPV is probably a reason why mass campaigns with OPV have been shown to stop person-to-person transmission of wild poliovirus. In very rare cases, the administration of OPV results in vaccine-associated paralysis associated with a reversion of the vaccine strains to the more neurovirulent profile of wild poliovirus. In a few instances, such vaccine strains have become both neurovirulent and transmissible and have resulted in infectious poliomyelitis.
- Pcv is a 13 valent vaccine, given to children prior to age 2 as they are able to mount an immune response to this. Pcv 23 is a polysaccharide given th ppl with certain conditions Greater than 65 PCV23 is recommended 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 (particularly C1, C2, C3, and C4), and phagocytic disorders (excluding chronic granulomatous disease) generalized malignancy HIV infection Hodgkin disease, leukemia, lymphoma, and multiple myeloma immunosuppression due to treatment with medication, including long-term systemic corticosteroids, and radiation therapy solid organ transplantation; for bone marrow transplantation
- By vaccinating these individuals with a pertussis booster a pool of persons is established around the newborn who are themselves protected from getting pertussis and passing it on to the infant, thereby creating a "cocoon" of protection around the newborn . Several layers of contacts (the contacts, the contacts' contacts, the contact's contacts' contacts, etc.) may be vaccinated Some vaccines will protect even if they are given just after infection, but even if the vaccine does not, ring vaccination can prevent the virus from being transmitted again, to the contacts' contacts
- Common, minor reactions These occur within a day or two of immunization (except for measles/MMR - 6 to 12 days after immunization) and they only last one to a few days. Local reactions include pain, swelling and/or redness at the injection site and can be expected in about 10% of vaccinees, except for those injected with DTP, or tetanus boosters, where up to half can be affected. BCG causes a specific local reaction that starts as a papule (lump) two or more weeks after immunization that then becomes ulcerated and heals after several months, leaving a scar. Individuals with dormant tuberculosis infection often have an accelerated response to BCG. Keloid (thickened scar tissue) from the BCG lesion is more common among Asian and African populations. Systemic reactions include fever and occur in about 10% or less of vaccinees, except for DTP where it is again about half. Other common systemic reactions (e.g., irritability, malaise, ‘off-colour’, anorexia) can also occur after DTP. For measles/MMR and OPV the systemic reactions arise from vaccine virus infection. Measles’ vaccine causes fever, rash and/or conjunctivitis, and affects 5-15% of vaccinees. It is very mild compared to ‘wild’ measles, but for severely immunocompromised individuals, it can be severe, even fatal. Vaccine reactions for mumps (swollen parotid gland) and rubella (arthralgia and swollen lymph nodes) affect less than 1% of children. Rubella vaccine causes symptoms more often in adults, with 15% suffering from arthralgia. Systemic reactions from OPV affect less than 1% of vaccinees with diarrhoea, headache, and/or muscle pain.
- Oral Polio- VVAP-VAPP is caused by a strain of poliovirus that has genetically changed in the intestine from the original attenuated vaccine strain contained in OPV. · It is associated with a single dose of OPV administered in a child or can occur in a close unvaccinated or non-immune contact of the vaccine recipient who is excreting the mutated virus. ROTAVIRUS-INTUSSUSCEPTION