6. IMMUNOLOGIC AGENTS: VACCINES

Active Immunity

Occurs when the body’s immune response is stimulated by an antigen or when a pathogen enters the body

Natural Acquired Active Immunity

Occurs from exposure to a pathogen or disease (e.g., getting sick with chickenpox and becoming immune)

Active Acquired Artificial Immunity

Occurs when a weakened antigen or component of a pathogen is injected into an individual as a vaccination, which then stimulates an immune response (e.g., receiving a measles vaccine)

Passive Immunity

Occurs when the body receives antibodies from an outside source.

Natural Passive Immunity

Antibodies are transferred naturally (e.g., from mother to fetus via placenta, or to infant via breast milk). The body produces its own antibodies

Acquired Passive Immunity

Body receives antibodies from an outside source (e.g., injection of immune globulin).

Community Immunity (Herd Immunity)

Occurs when most of the community is immunized against contagious diseases, allowing protection of those not immunized. When most of the community is NOT immunized, there is an increased risk for the spread of contagious disease

Vaccination

• Definition: Involves the administration of a small amount of antigen, capable of stimulating an immune response, without typically producing the actual disease.

• Purpose: A simple, safe, and effective way of protecting people against harmful diseases before they come into contact with them. It trains your immune system to create antibodies.

Traditional Vaccines (Whole-cell inactivated vaccines)

Mechanism of Action: Contain the whole or components of an inactivated (killed) microorganism. The killing process removes infectivity but retains antigenicity. When administered, these inactivated pathogens present their antigens to the immune system, stimulating antibody production and cellular immune responses without causing the disease

Attenuated Viruses (Live-attenuated vaccines)

• Mechanism of Action: Composed of live, attenuated (weakened) microorganisms. These vaccines contain a live, but weakened, form of the virus or bacteria that can replicate within the vaccinated individual but typically does not cause overt disease. This replication mimics a natural infection, leading to a strong, long-lasting cellular and humoral immune response.

• Caution: Immunocompromised persons should avoid live vaccines due to the risk of the attenuated pathogen causing actual disease.

Toxoids:

• Mechanism of Action: Inactivated toxins that can no longer produce harmful diseases but do stimulate the formation of antitoxins (antibodies against the toxin), which produces active immunity. The toxin is chemically treated to render it harmless while retaining its ability to provoke an immune response.

• Example: Tetanus toxoid.

Conjugate Vaccines

• Mechanism of Action: Designed for pathogens with polysaccharide capsules (e.g., Haemophilus influenzae type B). Polysaccharides alone are poor antigens for young children. Conjugate vaccines covalently link the polysaccharide from the disease-causing microorganism to a protein carrier (e.g., a toxoid from an unrelated organism like diphtheria or tetanus toxoid). This protein carrier converts the polysaccharide into a T-cell-dependent antigen, resulting in a stronger, more robust, and longer-lasting immune response, and also induces immunological memory.

• Example: H. influenzae type B (Hib) vaccine.

Recombinant Subunit Vaccines:

• Mechanism of Action: Involve inserting some of the genetic material (e.g., DNA) encoding a specific antigen (e.g., a surface protein) of a pathogen into another cell or organism (e.g., yeast or bacteria). This host cell then mass-produces the antigen. The purified antigen is then used as the vaccine, stimulating an immune response without exposing the recipient to the whole pathogen's genetic material.

• Example: Hepatitis B (Hep B) vaccine.

Adjuvant

• Mechanism of Action: A substance added to a vaccine to increase the body's immune response to the vaccine. Adjuvants work by various mechanisms, such as forming a depot at the injection site to allow for slower antigen release, enhancing antigen uptake by antigen-presenting cells (APCs), or stimulating inflammatory responses that activate immune cells.

• Example: Aluminum salts (e.g., aluminum hydroxide, aluminum phosphate, or aluminum potassium sulfate)

How are vaccines developed and tested?

• Phase I: Given to a small number of volunteers to assess safety, confirm immune response generation, and determine the right dosage.

• Phase II: Given to hundreds of volunteers, closely monitored for side effects, to further assess ability to generate an immune response.

• Phase III: Given to thousands of volunteers; some receive the investigational vaccine, others a placebo (or comparator vaccine), to evaluate efficacy and further assess safety in a larger population.

Vaccines for Preventable Diseases

All inactivated vaccines require refrigerator storage temperatures between 35°F and 46°F (2°C and 8°C), with a desired average temperature of 40°F (5°C).

BCG (Bacillus Calmette-Guérin) Vaccine

• Type and Classification: Live attenuated bacteria (weakened Mycobacterium bovis).

• Skin Test: Tuberculin skin test/Mantoux test (ID) needed before vaccination (in some regions/protocols, particularly if TB exposure is suspected).

• Route: Intradermal (ID).

• Schedule and Doses: 1 birth dose (0.05 mL) if at birth/Anytime after birth.

• Contraindications: Persons with impaired immunity (symptomatic HIV infection, known or suspected congenital immunodeficiency, leukemia, lymphoma, or generalized malignant disease); immunosuppressive treatment (corticosteroids, alkylating agents, antimetabolites, radiation); in pregnancy.

Hepa B Vaccine

• Type and Classification: Recombinant subunit vaccine (RNA recombinant, plasma derived from virus).

• Skin Test: Hepatitis B panel test (e.g., HBsAg, anti-HBsAg) before vaccination may be done for screening, but not a routine "skin test" for vaccine administration.

• Route: Intramuscular (IM).

• Schedule and Doses: 3 doses / 1 at birth. OK for pregnant and lactating mothers.

• Storage: Should not be frozen.

DPT (Pentavax - DTaP-IPV-Hib-HepB combo)

• Type and Classification: D-toxoid, P-killed bacteria (acellular pertussis component in DTaP), T-toxoid, HB-RNA recombinant (Hepatitis B), Hib-conjugate vaccine (Haemophilus influenzae type b/bacterial meningitis).

• Skin Test: Skin (prick and intradermal) tests are not routinely performed with corresponding vaccine components prior to administration.

• Route: IM.

• Schedule and Doses: Single dose of 0.5 mL / Three primary doses typically at 6 weeks, 10 weeks, and 14 weeks.

• Contraindications: Severe reaction to a previous dose, such as shock, persistent screaming, fever over 40.5°C, or serious neurological symptoms (e.g., encephalopathy not attributable to another cause within 7 days of previous dose).

Measles Vaccine

• Type and Classification: Live virus.

• Skin Test: No skin test needed.

• Route: Subcutaneous (Subcut).

• Schedule and Doses: 2 doses / First dose at 12 through 15 months of age. Second dose at 4 through 6 years of age.

• Contraindications: Contraindicated in pregnancy.

• Storage: Can be frozen.

Mumps Vaccine

• Type and Classification: Live attenuated virus.

• Skin Test: No skin test needed.

• Route: Subcut.

• Schedule and Doses: 2 doses / First dose at 12 through 15 months of age. Second dose at 4 through 6 years of age.

• Contraindications: Immunosuppression, allergy to neomycin and gelatin. Fetal damage not documented but theoretical risk due to live virus.

Rubella Vaccine

• Type and Classification: Live attenuated virus.

• Skin Test: No skin test needed.

• Route: Subcut.

• Schedule and Doses: 2 doses / First dose at 12 through 15 months of age. Second dose at 4 through 6 years of age.

• Contraindications: Pregnancy because of the theoretical teratogenic risk.

Pneumococcal Disease Vaccine

• Storage: Do not freeze vaccine or diluents, or expose to freezing temperatures.

• Pneumococcal Disease Type and Classification: Pneumococcal conjugate vaccine (PCV) and Pneumococcal polysaccharide vaccine (PPSV).

• Skin Test: Skin test not routinely needed before vaccination (unless for allergy testing).

• Route: IM/Subcut.

• Schedule and Doses:

  • PCV13 (Pneumococcal Conjugate Vaccine 13-valent): Typically 4 doses for children (2, 4, 6, and 12-15 months). For adults/older children, schedules vary; e.g., 2 years old - 64 years old: 8 weeks interval (if specific indication). 65 years old onwards: often a single dose followed by PPSV23.

  • PPSV23 (Pneumococcal Polysaccharide Vaccine 23-valent): For ages 2 years old - 18 years old: 8 weeks interval (if specific indication). 19 years old onwards: 1 year interval (if specific indication, usually a single dose for most adults over 65).

• EMPHASIS: Patients may get vaccinated; however, there are several strains of pneumonia-causing pathogens, meaning vaccination does not protect against all types of pneumonia.

Vaccines Contraindicated in pregnancy

• Measles vaccine

• Mumps vaccine

• Rotavirus vaccine

• Rubella vaccine

• Smallpox vaccine

• Varicella (Chickenpox) vaccine

• Reason: They are live attenuated vaccines and may cause presence of infection in the fetus due to the theoretical risk of vaccine virus transmission to the fetus.

immunocompromised individuals

live vaccines should be avoided in close contacts of severely___________

Varicella Vaccine (Chickenpox)

• Cause: Caused by a virus called VARICELLA ZOSTER.

• Who Needs Chickenpox Vaccine?

  • Children under age 13 years: Two doses (First dose at age 12 through 15 months old; Second dose at age 4 through 6 years old).

  • People 13 years or older: Two separate doses at least 28 days apart.

• Varicella Vaccine: Contraindicated if:

  • Pregnancy: Risk of fetal transmission (though possible side effects are still unknown).

  • Immunocompromised: From malignancies, high-dose systemic steroids, or other immunosuppressive therapy, as live vaccine cannot be done on an impaired immune system.

  • Acute illness: Fever or other active infections.

  • Tuberculosis: Have untreated active tuberculosis.

• Adverse Reactions:

  • Stevens-Johnson syndrome: A rare, severe disorder of the skin and mucous membranes. It's usually a reaction to medication that starts with flu-like symptoms, followed by a painful rash that spreads and blisters.

HPV (Human Papillomavirus)

• Nature: Sexually transmitted virus that causes cancer of the cervix, vagina, vulva, penis, and can cause genital warts, anal & oropharyngeal cancers in both men and women.

• EMPHASIS: These are commonly referred to as the vaccines for Cervical Cancer!

HepB, RV (Rotavirus), DTaP, Hib, PCV (Pneumococcal Conjugate Vaccine), Inactivated polio virus (IPV), MMR (Measles, Mumps, Rubella), varicella, and HepA

Childhood immunization schedule (birth – 6 years)

Tdap, influenza, HPV, meningococcal vaccinations.

Adolescent immunization schedule (7 – 18 years)

Adverse events following immunization (AEFI)

Any untoward medical occurrence which follows immunization, and which does not necessarily have a causal relationship with the usage of the vaccine. Reporting AEFI is crucial for vaccine safety surveillance.

Nursing Process: Vaccines

• Assessment (A):

  • Benefits and barriers to vaccination.

  • Current pregnancy status or plans for pregnancy.

  • Allergies (especially to vaccine components or previous doses).

  • History of adverse reactions to previous vaccines.

  • Presence of unvaccinated or immunocompromised household contacts.

  • Complete immunization history and history of vaccine-preventable diseases.

• Diagnosis (D):

  • Deficient knowledge about vaccination risks and benefits.

  • Ineffective health maintenance in adhering to the recommended immunization schedule.

  • Risk for injury due to adverse reactions to immunizations.

• Planning (P): Patient will:

  • Adhere to the recommended immunization schedule.

  • Remain free of adverse reactions or experience manageable ones.

• Interventions (I):

  • Administer all vaccines at separate sites and do not mix vaccines in the same syringe (unless specifically designed as a combination vaccine).

  • Document the record of the vaccine(s) taken thoroughly: vaccination date, route, and site of administration; vaccine type, manufacturer, lot number, and expiration date; and the name, business address, and title of the person administering the vaccine.

  • Keep epinephrine readily available for immediate use in case of anaphylactic reaction.

• PATIENT TEACHING:

  • General:

    • Avoid pregnancy for 1 month after live vaccines (e.g., MMR, varicella).

    • Avoid contact with severely immunocompromised persons for a specific period after receiving certain live vaccines (e.g., oral polio vaccine, rotavirus, varicella, zoster).

    • Maintain a personal vaccine immunization record.

    • Inform about the return date for the next vaccination(s) in a series.

  • Side Effects:

    • Discuss common side effects of vaccines (e.g., injection site soreness, redness, swelling, low-grade fever, muscle aches).

    • Offer suggestions for management of common side effects (e.g., cold compress to the injection site, acetaminophen or ibuprofen for soreness and fever, if appropriate).

• Evaluation (E):

  • Adherence to the recommended immunization schedule.

  • Patient remains free from adverse reactions or manages them effectively.

  • Achievement of protective immunity (if verifiable by serology).