NExT Community Medicine and Public Health (Preventive and Social Medicine) Syllabus

What is the secondary attack rate and its formula?

Secondary attack rate = number of new cases among contacts within one incubation period of the primary case / total susceptible contacts × 100. It measures infectiousness and person-to-person spread.

Define basic reproduction number (R0) and herd immunity threshold.

R0 = average number of secondary cases produced by one infectious case in a fully susceptible population. Herd immunity threshold = 1 − 1/R0; the proportion that must be immune to halt sustained transmission.

What is the incubation period, and why is it epidemiologically important?

Incubation period = time interval between entry of the pathogen (infection) and onset of clinical symptoms. It helps identify the time/source of exposure, define quarantine duration, and interpret epidemic curves.

State the chemoprophylaxis drug and regimen used for close contacts of meningococcal meningitis.

Rifampicin (600 mg twice daily for 2 days in adults) is the standard chemoprophylaxis; ciprofloxacin (single dose) or ceftriaxone are alternatives for close contacts.

Which mosquito transmits malaria, dengue, and filaria respectively in India?

Malaria – female Anopheles; Dengue (and chikungunya, Zika) – Aedes aegypti; Bancroftian filariasis – Culex quinquefasciatus (Brugian filaria – Mansonia).

What is the cold chain, and what are the recommended storage temperatures for vaccines?

Cold chain = the system of storing and transporting vaccines at recommended low temperatures from manufacture to administration. Vaccines are stored at +2°C to +8°C in refrigerators (ILR); some (OPV) kept frozen at −20°C in deep freezers at higher levels.

Which vaccines are most heat-sensitive and which are most sensitive to freezing?

Most heat-sensitive: OPV (most), then measles and BCG. Most freeze-sensitive (damaged by freezing): the adsorbed/liquid vaccines — DPT, DT, TT, Hepatitis B, and IPV.

List the vaccines given at birth under India's Universal Immunization Programme (UIP).

At birth: BCG, OPV-0 (zero dose), and Hepatitis B birth dose. (Some states also give the first dose of vaccines per the national schedule.)

What is the difference between live attenuated and killed (inactivated) vaccines, with examples?

Live attenuated vaccines (BCG, OPV, measles, MMR) contain weakened organisms, induce strong long-lasting immunity, usually single/few doses, contraindicated in immunocompromised/pregnancy. Killed/inactivated vaccines (IPV, Hepatitis B, rabies, cholera) are safer but need multiple doses/boosters.

What does a Vaccine Vial Monitor (VVM) indicate?

A VVM is a heat-sensitive label on the vial that changes color with cumulative heat exposure. When the inner square is the same color or darker than the outer ring, the vaccine has exceeded heat exposure and must be discarded.

What is the open vial policy in immunization?

Opened multidose vials of OPV, DPT, TT, Hepatitis B, and pentavalent (without preservative-related restriction concerns) may be used in subsequent sessions up to 28 days if cold chain maintained, VVM acceptable, expiry not passed, and no contamination. BCG and reconstituted measles/MMR must be discarded within 4 hours.

List the major modifiable risk factors common to non-communicable diseases (NCDs).

Tobacco use, harmful alcohol use, unhealthy diet (high salt/fat/sugar), and physical inactivity. These lead to intermediate risk factors: raised blood pressure, raised glucose, abnormal lipids, and overweight/obesity.

Define Body Mass Index (BMI) and the WHO cut-offs (with Asian modification).

BMI = weight (kg) / height (m²). WHO: underweight <18.5, normal 18.5–24.9, overweight 25–29.9, obese ≥30. Asian-Indian cut-offs: overweight ≥23, obese ≥25.

Name the Indian national program for NCD prevention and screening.

The National Programme for Prevention and Control of Non-Communicable Diseases (NP-NCD, formerly NPCDCS) targets diabetes, cardiovascular disease, and common cancers (oral, breast, cervical), with population-based screening for those aged 30+.

Define zoonosis and give three examples relevant to India.

A zoonosis is a disease/infection naturally transmissible between vertebrate animals and humans. Examples: rabies (dog), plague (rodent/flea), brucellosis (cattle/goats), leptospirosis (rodent urine), Kyasanur Forest Disease (monkey/tick).

Describe the categories of animal bite and corresponding rabies post-exposure prophylaxis.

Category I (touching/licking intact skin): no PEP, wash. Category II (minor scratches/abrasions without bleeding): wound wash + anti-rabies vaccine. Category III (transdermal bites, licks on broken skin/mucosa, bat exposure): wound wash + vaccine + Rabies Immunoglobulin (RIG).

List the five cleanliness/WASH interventions ('F-diagram' barriers) to prevent fecal-oral disease transmission.

Barriers blocking fecal-oral spread via the 5 F's (Fluids, Fingers, Flies, Fields/Floors, Food): safe water supply, sanitary excreta disposal (latrines), hand washing, food hygiene, and fly/vector control.

What are the permissible standards for residual chlorine and turbidity in drinking water?

Free residual chlorine should be ≥0.5 mg/L after 1 hour of contact (minimum contact period 1 hour). Acceptable turbidity is ≤1 NTU (permissible up to 5 NTU). These ensure microbiological safety.

Define the Orthotolidine (OT) test and its purpose in water treatment.

The orthotolidine test estimates free and combined residual chlorine in water by producing a yellow color, used to ensure adequate chlorination for disinfection (free residual chlorine target ≥0.5 mg/L).

Which air pollutant is the chief indicator of vehicular pollution health risk, and what is PM2.5?

PM2.5 = particulate matter ≤2.5 micrometers; it penetrates deep into alveoli, causing respiratory and cardiovascular disease, and is a key indicator of harmful air pollution. CO and NO2 are also major vehicular pollutants.

Define the Maternal Mortality Ratio (MMR) and its formula.

MMR = number of maternal deaths (during pregnancy or within 42 days of termination) per 100,000 live births. India's SDG target is to reduce MMR below 70 per 100,000 live births.

Differentiate Infant Mortality Rate (IMR), Neonatal Mortality Rate, and Under-5 Mortality Rate.

IMR = deaths under 1 year / 1000 live births. Neonatal MR = deaths within 28 days / 1000 live births. Under-5 MR = deaths under 5 years / 1000 live births. Neonatal deaths form the largest share of infant mortality in India.

What are the components of the recommended antenatal care (ANC) package in India?

At least 4 (now 8 per WHO) ANC visits; first visit in first trimester; TT/Td immunization; IFA (iron-folic acid) supplementation; weight/BP monitoring; abdominal exam; lab tests (Hb, urine, blood group, VDRL, HIV); and identification of high-risk pregnancies.

Describe the components of IMNCI (Integrated Management of Neonatal and Childhood Illness).

IMNCI is a strategy to manage the major causes of childhood death—pneumonia (ARI), diarrhea, measles, malaria, malnutrition—plus newborn care, through assess-classify-treat protocols, improving health-worker skills, health systems, and family/community practices.

What does ORS (oral rehydration solution) contain and its rationale (WHO low-osmolarity formula)?

Low-osmolarity ORS contains sodium, potassium, chloride, citrate, and glucose (osmolarity ~245 mmol/L). Glucose-coupled sodium absorption restores fluid; the low-osmolarity formula reduces stool output, vomiting, and need for IV fluids.

What are the three tiers of rural health care delivery in India and their population norms?

Sub-centre (1 per 5000 plain / 3000 hilly-tribal) — most peripheral, staffed by ANM/HW; Primary Health Centre/PHC (1 per 30,000 plain / 20,000 hilly) — first medical-officer contact; Community Health Centre/CHC (1 per 1,20,000 plain / 80,000 hilly) — 30-bed referral with 4 specialists.

What is the Ayushman Bharat scheme's two components?

1) Health and Wellness Centres (now Ayushman Arogya Mandirs) delivering comprehensive primary care; 2) Pradhan Mantri Jan Arogya Yojana (PM-JAY), providing health insurance cover of ₹5 lakh per family per year for secondary and tertiary hospitalization to poor families.

State the demographic cycle stages and where India currently falls.

Stages: 1) High stationary (high birth & death rates); 2) Early expanding (death rate falls); 3) Late expanding (birth rate falls); 4) Low stationary (both low); 5) Declining. India is in the late expanding stage, with falling birth and low death rates.

Define the Total Fertility Rate (TFR) and the replacement-level value.

TFR = average number of children a woman would bear during her reproductive life (15–49 years) at current age-specific fertility rates. Replacement-level fertility = 2.1; India's TFR has reached ~2.0, at/below replacement.

List the temporary (spacing) and permanent contraceptive methods promoted under India's Family Planning Programme.

Spacing/temporary: condoms (Nirodh), oral pills (Mala-N/Chhaya), IUCD (Cu-T 380A, 375), and injectable Antara (DMPA). Permanent/terminal: male vasectomy (NSV) and female tubectomy/laparoscopic ligation.