Midwife Licensure Exam Community & Public Health — Communicable Disease Control & ImmunizationDetailed Explanation

Levels of Prevention in Communicable Disease Control

Prevention in communicable disease is organized into three levels based on Leavell and Clark's model, which aligns closely with Maslow's hierarchy in terms of addressing physiological safety and health promotion needs. Understanding which level a nursing intervention belongs to is a common NLE question format. **Primary Prevention** aims to prevent disease from ever occurring. It targets healthy individuals and populations. Key activities include health education, immunization, environmental sanitation, safe water supply, adequate nutrition, and vector control. This is the most cost-effective level of prevention because it avoids the disease entirely. Immunization is the textbook example of primary prevention — specifically, it is called 'specific protection,' which is the second sub-level under primary prevention (the first sub-level being 'health promotion'). **Secondary Prevention** focuses on early detection and prompt treatment of disease in its early or subclinical stages. The goal is to shorten the duration of illness, prevent spread, and avoid complications. Nursing activities here include case-finding (e.g., sputum microscopy for TB, rapid antigen tests for dengue), screening programs, contact tracing, and early initiation of treatment. In the community setting, this is where the nurse serves as a case detector and treatment initiator. **Tertiary Prevention** aims to limit disability and facilitate rehabilitation for individuals who already have established disease. This includes managing complications of TB (e.g., hemoptysis, respiratory failure), rehabilitation after polio-related paralysis, and community reintegration of leprosy patients. The goal is to restore maximum function and prevent further deterioration. Remember the mnemonic: **P-S-T = Prevent, Screen/Treat, Rehabilitate**.

Types of Immunity

Understanding immunity is fundamental to understanding why we vaccinate and how vaccines work. Immunity is broadly classified as **active** or **passive**, and each has a natural and artificial form. **Active Immunity** means the individual's own immune system produces antibodies in response to an antigen. This process takes time (days to weeks) but produces **long-lasting, memory-based protection**. There are two types: - **Natural Active Immunity**: Acquired by actually having the disease (e.g., a child who survives measles develops lifelong immunity to that measles serotype). The body produces antibodies naturally after infection. - **Artificial Active Immunity**: Acquired through vaccination/immunization. The vaccine introduces an antigen (weakened, killed, or component of a pathogen) to stimulate the immune system to produce antibodies without causing full disease. Examples include BCG, MMR, OPV, and DPT vaccines. **This is the basis of the EPI.** **Passive Immunity** means the individual receives ready-made antibodies from an external source. This provides **immediate but temporary** protection because the antibodies are not self-produced and will eventually be broken down. There are two types: - **Natural Passive Immunity**: Maternal antibodies transferred to the fetus through the **placenta** (IgG) or to the newborn through **breast milk/colostrum** (IgA). This is why exclusively breastfed infants have some protection against infections in the first months of life. This is also why the measles vaccine is given at 9 months — maternal measles antibodies wane by then and could otherwise neutralize the vaccine. - **Artificial Passive Immunity**: Receiving immunoglobulins, antisera, or antitoxins (e.g., tetanus immunoglobulin for an unvaccinated wound patient, rabies immunoglobulin for post-exposure prophylaxis, hepatitis B immunoglobulin for a newborn of an HBsAg-positive mother). This provides immediate protection but no memory. **Herd Immunity** (Community Immunity): When a sufficiently high proportion of a population is immune (through vaccination or prior infection), the pathogen cannot spread efficiently even to unvaccinated individuals. This indirectly protects those who cannot be vaccinated (e.g., immunocompromised patients, very young infants). The threshold varies by disease — measles requires ~95% coverage for herd immunity; polio requires ~80–85%.

Expanded Program on Immunization (EPI)

The EPI is the cornerstone of communicable disease control for children in the Philippines. Every community health nurse must know the EPI schedule, the rationale behind it, and the legal framework. **Legal Foundation:** - **Presidential Decree 996 (1976)**: Established the EPI and mandated compulsory basic immunization for children under 8 years old. - **RA 10152 — Mandatory Infants and Children Health Immunization Act of 2011**: Updated and strengthened the mandate for free routine immunization, including Hepatitis B within 24 hours of birth. This is the current governing law. **Original Six Target Diseases (Classic EPI):** Tuberculosis, Diphtheria, Pertussis (whooping cough), Tetanus, Poliomyelitis, and Measles. Remember the mnemonic: **TD-PTM** or 'The Disease Pushes To Misery' = TB, Diphtheria, Pertussis, Tetanus, Measles, (Polio). **Current EPI Routine Infant Schedule (Philippine DOH):** 1. **BCG (Bacillus Calmette-Guérin)**: Given at **birth** (or anytime thereafter). Protects against severe forms of TB (tuberculous meningitis, miliary TB) in children. Route: **INTRADERMAL**, dose **0.05 mL**, right deltoid/upper arm. A successful vaccination produces a small wheal at injection, then a papule, ulcer, and finally a small scar at 2–3 months. The **PPD reaction / Koch's phenomenon** — an accelerated or exaggerated reaction to BCG — indicates prior TB exposure. For older children (not infants), the dose is 0.1 mL. 2. **Hepatitis B Monovalent (HepB birth dose)**: Given **at birth, within 24 hours**. Route: **Intramuscular (IM)**, 0.5 mL, vastus lateralis (anterolateral thigh in infants). This birth dose prevents perinatal mother-to-child transmission of Hepatitis B — the most critical time to protect the newborn. 3. **Pentavalent Vaccine (DPT-HepB-Hib)**: Given at **6, 10, and 14 weeks** of age. This is a combination vaccine protecting against Diphtheria, Pertussis (whooping cough), Tetanus, Hepatitis B, and Haemophilus influenzae type b (Hib — a major cause of bacterial meningitis and pneumonia in children). Route: **IM**, 0.5 mL, vastus lateralis. **Minimum interval between doses: 4 weeks (28 days).** NEVER give pentavalent to a child who had severe anaphylaxis or encephalopathy within 7 days of a previous dose. 4. **OPV (Oral Polio Vaccine)**: Given at **6, 10, and 14 weeks**. A **live attenuated** oral vaccine. Route: **Oral**, 2–3 drops. OPV provides intestinal immunity (IgA), which is important for interrupting fecal-oral transmission of poliovirus in the community. 5. **IPV (Inactivated Polio Vaccine)**: Given at **14 weeks and 9 months** (2 doses). Route: **IM**, 0.5 mL. IPV was added to the schedule to provide parenteral (systemic) immunity and to address the rare risk of vaccine-associated paralytic poliomyelitis (VAPP) from OPV alone. 6. **PCV (Pneumococcal Conjugate Vaccine)**: Given at **6, 10, and 14 weeks**. Protects against Streptococcus pneumoniae, a major cause of pneumonia, meningitis, and otitis media. Route: **IM**, 0.5 mL. 7. **MCV1 (Measles-Containing Vaccine, first dose — AMV or MMR)**: Given at **9 months**. Route: **Subcutaneous (SC)**, 0.5 mL, outer upper arm. Given at 9 months because maternal measles antibodies (natural passive immunity) wane by this age and would otherwise neutralize the vaccine. 8. **MCV2 (MMR — Measles, Mumps, Rubella, second dose)**: Given at **12 months**. Route: **SC**, 0.5 mL. **Key Route Summary (NLE FAVORITE):** - BCG = **Intradermal (ID)** - OPV = **Oral** - Measles/MMR = **Subcutaneous (SC)** - All others (Pentavalent/DPT, PCV, IPV, Hep B) = **Intramuscular (IM)** **Fully Immunized Child (FIC) vs. Completely Immunized Child (CIC):** - **FIC**: Child who received ALL of the following BEFORE reaching 12 months (first birthday): 1 BCG, 3 OPV, 3 Pentavalent, 1 measles-containing vaccine. - **CIC**: Child who completed the same set of antigens but between **12–23 months** of age. - **CPAB (Child Protected at Birth)**: Newborn protected from neonatal tetanus because the mother received at least **Td2** during pregnancy. **Tetanus (Td) Immunization for Women of Childbearing Age:** The Td schedule for women has 5 doses: - Td1: As early as possible in pregnancy — gives NO protection yet (priming dose) - Td2: At least 4 weeks after Td1 — protects for ~3 years; **this dose protects the infant from neonatal tetanus** - Td3: At least 6 months after Td2 — protects for ~5 years - Td4: At least 1 year after Td3 — protects for ~10 years - Td5: At least 1 year after Td4 — **LIFETIME protection** Remember: **Td2 = 3 years; Td5 = LIFETIME**.

Cold Chain Management

The cold chain is the temperature-controlled supply chain that keeps vaccines safe and effective from the time they are manufactured until they are administered to a child. A broken cold chain is a major cause of vaccine failure — children may receive vaccines that appear fine but have lost their potency. As a community health nurse, maintaining the cold chain at the health center level (RHU/BHS) is a critical responsibility. **Cold Chain Temperature Requirements:** - **Health center / RHU level (last mile):** Vaccines must be stored in a refrigerator at **+2°C to +8°C**. This applies to all routinely used vaccines at the barangay/RHU level. - **Regional and Provincial level:** Vaccines stored in freezers at **−15°C to −25°C** — specifically for long-term storage of OPV and measles vaccines. - **District / Municipal level:** Intermediate storage, usually refrigerator temperature +2°C to +8°C. **Heat Sensitivity (Most to Least Heat-Sensitive — where to store in the coldest part):** - **Most heat-sensitive:** **OPV** (must be frozen for long-term storage; most vulnerable to heat damage at the field level) - **Second most heat-sensitive:** Measles and BCG vaccines - **Least heat-sensitive:** DPT, DT, Td, Hepatitis B, Pentavalent In a refrigerator, the coldest area is usually the middle shelf (away from the door and freezer compartment). Place OPV and measles/BCG in the middle; HepB, DPT, Pentavalent at the bottom/door shelves. **CRITICAL: Freeze-Sensitive Vaccines (MUST NOT BE FROZEN):** The following vaccines are DESTROYED by freezing — they must never be placed in the freezer or stored next to ice packs directly: - **DPT (diphtheria-pertussis-tetanus)** - **Hepatitis B** - **Td (tetanus-diphtheria)** - **Pentavalent (DPT-HepB-Hib)** - **PCV (pneumococcal)** - **IPV** Freezing causes these vaccines to form micro-precipitates, destroying their antigenicity. The **Shake Test** is used to detect frozen (damaged) freeze-sensitive vaccines: Shake the suspect vaccine and a control vial; if the suspect vial takes longer to re-dissolve or shows distinct clumping vs. the control, it has been frozen and must be discarded. **Vaccine Vial Monitor (VVM):** The VVM is a heat-sensitive label on vaccine vials that changes color with cumulative heat exposure. A VVM changes from light (safe to use) to dark (discard). The nurse checks the VVM before every vaccination. If the inner square is darker than the outer circle, discard the vaccine. **FEFO Principle:** **First Expiry, First Out** — vaccines that expire soonest are used first, regardless of when they arrived. This minimizes vaccine wastage. Never use FIFO (First In, First Out) for vaccines. **Other Cold Chain Practices:** - Record refrigerator temperatures twice daily (morning and afternoon) in the temperature log - Do not store food, drinks, or specimens in the vaccine refrigerator - Keep vaccines in their original packaging - Never leave vaccines at room temperature for more than 30 minutes during a session - Use vaccine carriers with ice packs for outreach immunization activities - Report cold chain breaks (power outages, temperature excursions) to the supervisor immediately

National TB Control Program (NTP) and DOTS

Tuberculosis (TB) remains one of the Philippines' most significant public health problems. The Philippines is among the high-burden TB countries globally. The **National Tuberculosis Control Program (NTP)** uses the internationally recommended **DOTS (Directly Observed Treatment, Short-course)** strategy as its core approach. **Diagnosis:** Under the current Philippine NTP, **Xpert MTB/RIF (GeneXpert)** is the recommended **first-line diagnostic test**. It is a rapid molecular test that simultaneously detects Mycobacterium tuberculosis AND rifampicin resistance in approximately 2 hours. It is particularly valuable for diagnosing drug-resistant TB and TB in HIV-positive patients. **Direct Sputum Smear Microscopy (DSSM)** remains in use, primarily for **treatment monitoring and follow-up** sputum examinations. Sputum specimens for DSSM are collected as 'spot–morning' or 'spot–spot' specimens. **The 5 Elements of DOTS:** 1. **Political commitment** with increased and sustained financing — government ensures resources are available 2. **Case detection through quality-assured bacteriology** — use of GeneXpert/DSSM with quality control 3. **Standardized treatment regimens with direct observation of treatment** — a health worker or trained treatment partner watches the patient swallow EVERY dose 4. **Uninterrupted supply of quality-assured anti-TB drugs** — no stock-outs 5. **A standardized recording and reporting system** to monitor treatment outcomes and program performance The **third element** — direct observation of treatment — is the most critical and distinctive feature. It prevents drug resistance caused by incomplete or inconsistent treatment. **First-Line Anti-TB Drugs:** Remember the mnemonic **HRZES** (or 'Heroes'): - **H = Isoniazid (INH)** - **R = Rifampicin (RIF)** - **Z = Pyrazinamide (PZA)** - **E = Ethambutol (EMB)** - **S = Streptomycin (SM)** **Treatment Categories:** **Category I (New Cases):** For patients who have never been treated for TB before (new smear-positive or negative pulmonary TB, extrapulmonary TB, severe forms). Regimen: **2HRZE / 4HR** - Intensive phase: 2 months of Isoniazid + Rifampicin + Pyrazinamide + Ethambutol (HRZE) — 4 drugs - Continuation phase: 4 months of Isoniazid + Rifampicin (HR) — 2 drugs - Total duration: **6 months** **Category II (Previously Treated Cases):** For patients who have been treated before — relapse, treatment after failure, or treatment after being lost to follow-up. Regimen: **2HRZES / 1HRZE / 5HRE** - Intensive phase: 2 months HRZES (adding Streptomycin) + 1 month HRZE - Continuation phase: 5 months HRE - Total duration: **8 months** **Drug-Resistant TB** is managed under **PMDT (Programmatic Management of Drug-Resistant TB)** using specialized second-line drug regimens. **Drug Side Effects (NLE Favorites):** - **Rifampicin**: Orange-red discoloration of urine, tears, sweat — **this is NORMAL; reassure the patient** - **Isoniazid**: Peripheral neuropathy (tingling/numbness in extremities) — give **pyridoxine (Vitamin B6)** to prevent - **Ethambutol**: Optic neuritis — visual changes, color blindness (check visual acuity monthly) - **Streptomycin**: Ototoxicity (hearing loss, tinnitus) and nephrotoxicity - **Pyrazinamide**: Hepatotoxicity (liver enzyme elevation), hyperuricemia (gout) **Nursing Responsibilities in TB/DOTS:** - Directly observe each dose — the patient swallows medication in the nurse's presence - Identify and train a **treatment partner** (trusted community member/family member) to observe doses when the nurse is unavailable - Conduct contact tracing — screen all household members for TB symptoms and arrange sputum testing - Teach cough etiquette (cover mouth, proper tissue disposal, ventilate rooms) - Monitor for drug side effects at every visit - Complete and accurate documentation in the TB treatment card - Coordinate with the DOH NTP program supervisor for reporting

Dengue Control — DOH 4-S Strategy

Dengue is a major public health emergency in the Philippines, causing annual outbreaks. Every community health nurse must know the disease, its vector, and the DOH-endorsed control strategy. **Disease Overview:** Dengue is caused by the Dengue virus (DENV), a flavivirus with **4 serotypes: DENV-1, DENV-2, DENV-3, DENV-4**. Infection with one serotype provides **lifelong immunity to THAT serotype only**. A subsequent infection with a DIFFERENT serotype is associated with a higher risk of severe dengue (dengue hemorrhagic fever/dengue shock syndrome) — this is explained by the **antibody-dependent enhancement (ADE)** phenomenon. **Vector:** - Primary vector: **Aedes aegypti** — a **day-biting** mosquito (most active 2 hours after sunrise and before sunset) - Secondary vector: Aedes albopictus - Breeding sites: **clean, stagnant water** in containers (water jars, flower vases, discarded tires, clogged gutters, coconut shells, pet water dishes) - Aedes aegypti is a domestic mosquito — it lives and breeds INSIDE and AROUND the home **Contrast with Malaria vector:** - Malaria is transmitted by the **Anopheles** mosquito, which is a **night-biting** mosquito. This distinction is frequently tested. **DOH 4-S Strategy Against Dengue:** 1. **S — Search and Destroy** mosquito breeding sites: Conduct regular 'clean-up drives' to eliminate standing water containers (overturn, empty, cover water containers; clean gutters; dispose of solid waste that collects water). This is the most important and cost-effective long-term control measure. 2. **S — Self-protection** measures: Use insect repellent, wear long-sleeved clothing, install window/door screens, sleep under mosquito nets during daytime naps, use mosquito coils. 3. **S — Seek early consultation** for fever: Patients with fever for 1–2 days and a dengue exposure history should see a health provider immediately. Early consultation allows monitoring for warning signs and prevents complications. Warning signs of severe dengue: severe abdominal pain, persistent vomiting, bleeding from any site, restlessness/altered consciousness, rapid breathing, sudden drop in temperature after fever. 4. **S — Support fogging/spraying** only during outbreaks in identified hotspot areas: Chemical fogging (using pyrethroid insecticides) kills adult mosquitoes. However, this is a REACTIVE measure (done during outbreaks), NOT a primary preventive measure for routine use. Fogging is ineffective against eggs and larvae. **Nursing Management Key Points:** - Maintain adequate hydration (oral rehydration if tolerating; IV fluids as ordered for severe dengue) - Monitor hematocrit, platelet count, and signs of plasma leakage - Platelet transfusion is NOT routinely done unless there is active bleeding with very low platelet count - AVOID aspirin and NSAIDs (increase bleeding risk) — use paracetamol for fever - Educate the community on warning signs and 4-S strategy **Other Locally Endemic Diseases (Brief Overview):** - **Malaria**: Transmitted by Anopheles mosquito (night-biting); control via bed nets treated with insecticide (LLINs), indoor residual spraying, and case management with artemisinin-based combination therapy (ACT). Endemic in Palawan, Mindanao, some Visayas areas. - **Schistosomiasis**: Caused by Schistosoma japonicum; intermediate host is the Oncomelania snail; endemic in Samar, Leyte, parts of Mindanao; control involves mollusciciding, health education, mass drug administration (praziquantel). - **Filariasis (lymphatic filariasis)**: Caused by Wuchereria bancrofti (mainly); transmitted by Culex mosquito; control via mass drug administration (diethylcarbamazine + albendazole). - **Leprosy (Hansen's Disease)**: Caused by Mycobacterium leprae; treated with multi-drug therapy (MDT); Philippines has near-elimination status (<1 case per 10,000 population). - **Rabies**: Transmitted by bite of infected animals (dogs most common in Philippines); prevention via post-exposure prophylaxis (PEP) — wound washing, rabies vaccine, rabies immunoglobulin (RIG) for severe bites.

PIDSR and Notifiable Diseases Reporting

The **Philippine Integrated Disease Surveillance and Response (PIDSR)** is the national system for reporting and responding to public health threats. As a community health nurse, timely and accurate reporting is both a professional and legal obligation under RA 9173 (Nursing Act of 2002), which mandates nurses to participate in disease surveillance activities. **Categories of Notifiable Diseases:** **Immediately Notifiable (within 24 hours):** These are diseases of epidemic potential, diseases targeted for elimination or eradication, and threats requiring urgent public health response. Examples: - **Acute Flaccid Paralysis (AFP)** — potential polio case - **Measles** and **neonatal tetanus** - **Cholera** - **Meningococcal disease** - **Rabies** - **Pandemic or novel influenza** - **Anthrax, plague, viral hemorrhagic fevers** **Weekly Notifiable (reported on a weekly basis):** These are endemic diseases with regular surveillance requirements: - **Dengue** - **Typhoid fever** - **Tuberculosis** - **Leptospirosis** - **Hepatitis A and B** - **Malaria** - **Influenza-like illness** **Nursing Role in PIDSR:** - **Identify** suspected cases using case definitions - **Report** to the Municipal/City Health Office within the required timeframe - **Investigate** — gather epidemiological information (who, what, where, when, how many) - **Implement** immediate control measures (isolation, contact tracing, environmental control) - **Evaluate** the response and follow up The **Nurse** at the RHU/community level is the first responder for surveillance — early detection and reporting triggers the public health response chain.

The FIC criteria require the following vaccines to be completed BEFORE reaching 12 months (1 year) of age: 1 dose BCG, 3 doses OPV, 3 doses Pentavalent (DPT-HepB-Hib), and 1 dose measles-containing vaccine (MCV1). This child has received all of these before 10 months of age — well within the FIC window. Note: IPV and PCV, while important, are not counted in the traditional FIC definition. The child meets all FIC criteria.

There are two problems: (1) OPV is the MOST heat-sensitive vaccine and should be stored in the COLDEST part of the refrigerator (middle shelves, away from the door and warming coils). Placing OPV near the door exposes it to the warmest temperatures inside the refrigerator. (2) DPT (along with Pentavalent, Hep B, Td) is a FREEZE-SENSITIVE vaccine. It must NEVER be frozen. Placing DPT in the freezer compartment will destroy its potency. The nurse must rearrange: OPV to the middle shelf, DPT to a shelf away from the freezer compartment but still within 2-8°C. If DPT was frozen, perform the shake test to assess viability.

Td1 (given at 16 weeks) is the priming dose — it provides NO protection yet. Td2 must be given at minimum 4 weeks after Td1, meaning at approximately 20 weeks of gestation (still well within the pregnancy, allowing adequate time). After Td2, the mother develops immunity (~3 years protection) and her antibodies cross the placenta to protect the newborn from neonatal tetanus. This is why Td2 must be given early enough in pregnancy to allow antibody development and placental transfer before delivery. She should be counseled to return for Td2 in 4 weeks.

Feeling better after 2 months means the intensive phase has suppressed the bacteria to the point where symptoms resolve, but TB bacilli are NOT completely eliminated yet. The continuation phase (4 months of HR) kills remaining dormant bacteria and prevents relapse. If stopped early: (1) Residual bacteria will multiply again, causing relapse; (2) Incomplete treatment creates conditions for drug-resistant mutations — leading to MDR-TB. The nurse should reinforce adherence, continue directly observing each dose, and document this counseling interaction. This is the core rationale for DOTS.

In the vaccine carrier: (1) OPV is the most heat-sensitive — keep it in the coldest position (center, surrounded by ice packs but in a waterproof container to prevent freezing from direct contact if OPV is considered for freezing — at the field level, OPV should be in refrigerator temperature range for the session). (2) MCV1 and BCG are also heat-sensitive and should be kept cool. (3) Pentavalent is FREEZE-SENSITIVE — direct contact with ice packs can freeze and destroy it. Wrap Pentavalent in a cloth or paper to prevent direct ice contact while keeping it cool. All vaccines must stay within 2-8°C during the outreach session.