Tell me tpt from this pdf and your data in comprehensive answer and rationale behind regimen

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tuberculosis preventive therapy isoniazid rifapentine regimen

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WHO 2023 2024 TB preventive therapy TPT guidelines 6H 3HP 1HP India

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Now I have comprehensive data from both the PDF, the PPTX (via markitdown on PDF version), and the medical textbook. Let me compose the full answer.

TB Preventive Therapy (TPT) — Comprehensive Guide

1. What is TPT?

TB Preventive Therapy (TPT) is treatment given to persons with TB infection (TBI) — formerly called Latent TB Infection (LTBI) — to prevent progression to active TB disease. The goal is interrupting the TB infection → active disease cascade rather than treating active disease.

Key rationale: Of all persons with TBI, 5–10% will develop active TB over their lifetime, with the highest risk in the first 1–2 years after initial infection. By reducing the viable bacillary population in dormant lesions, TPT prevents this reactivation.

2. Burden and Priority (India-Specific)

India carries the highest estimated burden of TB infection globally: ~35–40 crore (350–400 million) people have TBI
Risk of TB disease is >25× higher among household contacts of bacteriologically confirmed TB cases vs. the general population
Risk is 16–21× higher in HIV co-infection (PLHIV)
TB is the leading cause of death in PLHIV

3. Who Gets TPT — Priority Populations

Population	Testing Required Before TPT?
Household contacts of pulmonary TB (age ≥5 yrs)	Yes (test for TBI, rule out active TB first)
Children <5 years (HH contacts)	No testing needed — TPT directly
PLHIV	No testing needed — TPT directly regardless of TST/IGRA result
Immunocompromised (transplant, dialysis)	Test first
Other high-risk populations	As per national guidelines

WHO recommendation: All PLHIV who do not have evidence of active TB should receive preventive therapy, regardless of TST or IGRA result. Some data suggest 36-month duration is conditionally recommended for PLHIV in high-burden settings — Murray & Nadel's Textbook of Respiratory Medicine, p. 1167

4. Tests for TB Infection (Comparative)

Feature	TST	IGRA	Cy-Tb (New)
Sensitivity	High	High	High
Specificity	Low in BCG-vaccinated	High even in BCG-vaccinated	High even in BCG-vaccinated
Ease of use	Field-friendly but complex interpretation	Requires lab infrastructure	Field-friendly, single 5 mm cut-off
Cost	Low	High	Low
Special populations	Affected by age/HIV	Affected by low CD4	More robust at low CD4 and in children

Cy-Tb Skin Test (India, 2023)

A newer skin test using ESAT-6 and CFP-10 antigens (same as IGRA targets), approved by GOI in August 2023 for:

Age >18 years
Household contacts of pulmonary TB
Immunocompromised individuals

Universal cut-off: ≥5 mm induration (read at 48–72 hrs), irrespective of BCG or HIV status — reducing false-positive diagnosis. Contraindicated only in allergy to Lactobacillus lactis products.

Before initiating any TPT: active TB must be excluded — neither TST nor IGRA can distinguish LTBI from active TB. — Murray & Nadel's, p. 939

5. TPT Regimens — Side-by-Side Comparison

Feature	6H	3HP	1HP
Medicines	Isoniazid (H) alone	Isoniazid + Rifapentine	Isoniazid + Rifapentine
Duration	6 months	3 months	1 month
Frequency	Daily	Weekly	Daily
Total doses	180	12	28
Pill burden	1 pill/day	3 pills/week (FDC 150/150 for >14 yr)	2 pills/day
Pregnancy	Safe	Not known	—
ART interaction	No restriction	Contraindicated with PIs, NVP/NNRTIs, TAF	—
ART compatible	All	TDF, EFV 600 mg, DTG, RAL (no dose adjustment)	—

6. Dosage Details

6H — 6 Months Daily Isoniazid

Age	Dose
≥10 years	5 mg/kg/day (max 300 mg/day)
<10 years	10 mg/kg/day (range 7–15 mg/kg)

3HP — 12 Weekly Doses (Isoniazid + Rifapentine)

Age 2–14 years:

Weight	INH 100 mg tabs	RPT 150 mg tabs	FDC (150/150) tabs
10–15 kg	3	2	2
16–23 kg	5	3	3
24–30 kg	6	4	4
31–34 kg	7	5	5
>34 kg	7	5	5

Age >14 years (all weight bands ≥30 kg):

INH 300 mg × 3 tablets = 900 mg
RPT 150 mg × 6 tablets = 900 mg
Or FDC (300/300) × 3 tablets

1HP — 28 Daily Doses

INH: 300 mg/day, Rifapentine: 600 mg/day (regardless of weight)
Can be given as: HP FDC 300/300 mg × 2 tablets, or INH 300 mg + RPT 300 mg + RPT 150 mg × 4

7. Rationale Behind Each Regimen

6H (6-Month Isoniazid)

Mechanism: Isoniazid inhibits mycolic acid synthesis (InhA/KatG pathway), bactericidal against actively dividing and semi-dormant bacilli. Large U.S. Public Health Service trials in ~70,000 participants showed INH reduced TB incidence by ~80% during the treatment year and ~60% overall over 10–12 years follow-up. — Murray & Nadel's, p. 1167

Pros: Cheapest, long safety record, safe in pregnancy Cons: 180 doses → adherence challenge; hepatotoxicity risk (INH-induced hepatitis); peripheral neuropathy

3HP (3-Month Weekly Isoniazid + Rifapentine)

Mechanism: Rifapentine is a long-acting rifamycin (half-life ~14–17 hours vs. rifampin ~3 hours), allowing once-weekly dosing. Combination targets both dormant and semi-dormant bacilli. The PREVENT TB (ISONIACID + RIFAPENTINE) trial and subsequent network meta-analysis (PMID 36966788, Lancet Respir Med 2023) confirmed non-inferiority to 9H with superior completion rates.

Pros: Only 12 doses, high completion, shorter duration Cons: Drug interactions with rifamycins (antiretrovirals, oral contraceptives, see below); cannot be used in pregnancy (safety unknown)

1HP (1-Month Daily Isoniazid + Rifapentine)

Mechanism: Ultra-short course using daily high-dose rifapentine (600 mg) — maximizes drug exposure while compressing treatment duration. A randomized trial in PLHIV showed 1HP had similar effectiveness to 9H, with 97% vs. 90% completion. — Murray & Nadel's, p. 939

Pros: Highest completion rate, only 28 doses, similar efficacy to longer regimens Cons: Evidence primarily in PLHIV so far; rifapentine drug interactions still apply

A 2023 network meta-analysis (PMID 36966788, Lancet Respir Med) found rifamycin-containing regimens (3HP, 1HP, 4R) had significantly better treatment completion than INH-only regimens, with comparable or superior efficacy — supporting the shift toward shorter courses.

8. Pyridoxine (Vitamin B6) Supplementation

Isoniazid competitively inhibits pyridoxal phosphokinase → peripheral neuropathy via pyridoxine deficiency.

Who needs it:

Malnutrition, chronic alcohol dependence, HIV infection, renal failure, diabetes, pregnancy/breastfeeding

Doses:

Group	Pyridoxine Dose
Children	10 mg/day
Adults (general)	25 mg/day
Adult PLHIV	50 mg/day

Neuropathy is reversible on INH withdrawal + high-dose pyridoxine (100–200 mg/day therapeutically).

9. Drug Interactions

Rifamycins (Rifampicin, Rifapentine)

Potent CYP450 inducers → reduce plasma levels of oral/hormonal contraceptives: switch to DMPA every 8 weeks, higher-dose oestrogen (50 µg), IUD, or barrier method
Hormonal implants: shorten replacement interval from 12 to 8 weeks

3HP/1HP with ART (for PLHIV):

ART Drug	3HP/1HP Compatibility
All PIs (lopinavir, atazanavir, etc.)	Contraindicated
Nevirapine (NVP) / NNRTIs	Contraindicated
TAF (tenofovir alafenamide)	Contraindicated
Tenofovir (TDF), Efavirenz 600 mg, DTG, RAL	Compatible (no dose adjustment)

10. Contraindications

Type	Details
Absolute	Active TB disease (only one)
Relative	Acute or chronic hepatitis
Relative	Concurrent hepatotoxic drugs (e.g., nevirapine)
Relative	Peripheral neuropathy symptoms (tingling, numbness, burning)
Relative	Known hypersensitivity to any TPT drug

Liver function thresholds for withholding:

ASymptomatic: ALT/AST >5× ULN → withhold
Symptomatic (hepatitis sx): ALT/AST >3× ULN → withhold

Baseline LFTs are indicated before TPT in: liver disease, alcohol use, HIV, pregnancy/postpartum <3 months.

11. Treatment Completion Criteria (India Programme)

Regimen	Duration	Total Doses	Min doses for completion	Max allowed days
6H (daily)	6 mo	180	144 (80%)	239 days
3HP (weekly)	3 mo	12	11 (90%)	120 days
6Lfx (daily)	6 mo	180	144 (80%)	239 days
4R (daily)	4 mo	120	96 (80%)	160 days

6Lfx (levofloxacin-based, 6 months) is used when INH resistance is suspected (e.g., contacts of drug-resistant TB cases).

12. Summary: Choosing the Right Regimen

Patient Type                 Preferred Regimen
─────────────────────────────────────────────────
General adult/child          3HP (best completion + efficacy)
Pregnancy                    6H (only safe option)
PLHIV on TDF/EFV/DTG/RAL    3HP or 1HP
PLHIV on PI/NVP/TAF          6H (rifamycin-incompatible ART)
Child <2 years               6H
Drug-resistant TB contact    6Lfx

Sources:

Ministry of Health & Family Welfare, India — Guidelines for Programmatic Management of TB Preventive Treatment, July 2021 (your PDF)
Murray & Nadel's Textbook of Respiratory Medicine (Pulmonology library), pp. 938–939, 1167–1168
Winters N et al., Lancet Respir Med 2023 — PMID 36966788 (Rifamycin-containing TPT network meta-analysis)
Melnychuk L et al., Clin Infect Dis 2023 — PMID 37125482 (TPT adverse events systematic review)

Here is a comprehensive, exam-oriented breakdown of **TB Preventive Therapy (TPT)** under **NTEP (National TB Elimination Programme), India** — integrating NTEP guidelines, WHO 2020 recommendations, and Harrison's 21st edition. --- # TB Preventive Therapy (TPT) — NTEP | Complete MD Exam Guide --- ## 1. CONCEPT & RATIONALE - **TPT** = treatment given to prevent progression from **latent TB infection (LTBI)** → **active TB disease** - Previously called: *Isoniazid Preventive Therapy (IPT)*, *Chemoprophylaxis*, *Preventive Chemotherapy* - Estimated **1.7 billion** people worldwide have LTBI (>25% of global population) — the reservoir from which new TB cases emerge - TPT is a **pillar of TB elimination strategy** under **End TB strategy** and **National Strategic Plan (NSP) 2017–25** > NTEP renamed "IPT" → **"TPT"** to reflect availability of multiple regimens beyond isoniazid alone --- ## 2. TYPES OF TPT | Type | Definition | |---|---| | **Primary prophylaxis** | Given to LTBI-negative high-risk persons (e.g., HIV+ with no TB) to prevent initial infection or early disease | | **Secondary prophylaxis** | Given to LTBI-positive persons to prevent reactivation | --- ## 3. WHO IS ELIGIBLE FOR TPT? (NTEP Priority Groups) ### **Category A — Mandatory (High Priority)** | Group | Details | |---|---| | **PLHIV (People Living with HIV)** | All ages, regardless of TST/IGRA result; after ruling out active TB | | **Household contacts of bacteriologically confirmed pulmonary TB** | All ages | | **Child contacts < 5 years** of any TB patient | Regardless of TST status | | **Child contacts 5–14 years** | After ruling out active TB | ### **Category B — Recommended (Extended)** | Group | |---| | Patients on **anti-TNF therapy** (biologics) | | Patients on **dialysis** | | **Silicosis** patients | | **Transplant recipients** (organ or stem cell) | | **Diabetes mellitus** patients (selected) | | **Prisoners**, healthcare workers in high-burden settings | | **Undernourished** individuals | ### **Key NTEP Criteria for PLHIV:** - TST/IGRA **NOT mandatory** before starting TPT in PLHIV - TPT started after **ruling out active TB** (not based on immunological testing) --- ## 4. RULING OUT ACTIVE TB BEFORE STARTING TPT This is the **most critical step**. Use the **W4SS (4-symptom screen)**: > Any one of: **Cough, Fever, Night sweats, Weight loss** - If **any symptom present** → investigate for active TB first - If **all absent** → proceed with TPT - In PLHIV on ART: also consider **chest X-ray + sputum examination** if indicated **NTEP Algorithm:** ``` Eligible person identified ↓ Screen for active TB (W4SS) ↓ Active TB ruled out? YES → Start TPT NO → Evaluate and treat active TB first ``` --- ## 5. TPT REGIMENS — NTEP 2022 (Current Recommendations) ### **Primary Regimen for All Eligible Groups** | Regimen | Drug(s) | Duration | Frequency | Notes | |---|---|---|---|---| | **6H** | Isoniazid (H) | 6 months | Daily | Long-standing standard; still used | | **9H** | Isoniazid | 9 months | Daily | Used in HIV+; WHO preferred alternative | | **3HP** ⭐ | Isoniazid + Rifapentine | **3 months** | **Weekly** | NTEP preferred regimen; DOT required | | **3HR** | Isoniazid + Rifampicin | 3 months | Daily | Used where rifapentine unavailable | | **1HP** | Isoniazid + Rifapentine | **1 month** | Daily | Alternative; conditional recommendation | | **4R** | Rifampicin alone | 4 months | Daily | For INH-intolerant patients | ### **NTEP Current Preferred Regimen:** > **3HP (3 months weekly Isoniazid + Rifapentine)** — introduced under NTEP as the preferred short-course regimen due to better completion rates ### **Doses:** | Drug | Adult Dose | Pediatric Dose | |---|---|---| | Isoniazid (H) | 5 mg/kg/day (max 300 mg) | 10 mg/kg/day (max 300 mg) | | Rifampicin (R) | 10 mg/kg/day (max 600 mg) | 15 mg/kg/day | | Rifapentine (P) | Weight-based (see below) | ≥10 kg required | **Rifapentine weight-based dosing (3HP weekly):** - 10–14 kg: 300 mg - 14–25 kg: 450 mg - 25–32 kg: 600 mg - 32–50 kg: 750 mg - >50 kg: **900 mg** (max) --- ## 6. FOR SPECIAL POPULATIONS ### **Children < 2 years (Household Contacts)** - Regimen: **6H** (isoniazid daily × 6 months) - TST not mandatory; clinical assessment sufficient ### **Children 2–5 years** - 6H or **3HP** (if ≥10 kg body weight) ### **PLHIV** - All PLHIV should receive TPT (regardless of CD4 count, ART status, TST) - Preferred: **3HP** or **6H** - **Interaction alert**: Rifapentine + efavirenz — dose adjustment may be needed; rifabutin preferred if on certain PI-based ART ### **Pregnant Women** - TPT generally **deferred** until after delivery and completion of breastfeeding - Exception: PLHIV with high risk — **6H** preferred (rifamycins avoided in 1st trimester) - **Pyridoxine (Vitamin B6) 25–50 mg/day** must be co-administered with isoniazid in pregnancy ### **Drug-Resistant TB Contacts (MDR-TB contacts)** - Standard TPT **not recommended** (isoniazid/rifampicin may be ineffective) - Currently under **6–12 months of fluoroquinolone-based regimens** (levofloxacin) in research/programmatic settings - NTEP: monitor closely; no standardized DR-TPT regimen yet --- ## 7. MONITORING DURING TPT | Parameter | Frequency | |---|---| | Active TB symptom screening | Every visit (monthly) | | Hepatotoxicity symptoms (nausea, jaundice, abdominal pain) | Monthly | | Liver function tests (LFTs) | Baseline; repeat if symptomatic or high risk | | Pyridoxine supplementation | Given with INH in high-risk (alcoholics, DM, pregnancy, malnutrition, HIV) | ### **Stopping Rules:** - **Jaundice** or AST/ALT >3× ULN with symptoms → stop TPT - AST/ALT >5× ULN (asymptomatic) → stop TPT - Resume only after LFTs normalize --- ## 8. CONTRAINDICATIONS TO TPT | Contraindication | |---| | **Active TB disease** (must treat first) | | **Severe hepatic disease** / active hepatitis | | History of **INH-induced hepatitis** | | **Concurrent hepatotoxic drugs** (without close monitoring) | | Drug **interactions** (e.g., rifampicin + anticoagulants, OCPs, antiretrovirals) | --- ## 9. PYRIDOXINE (VITAMIN B6) CO-ADMINISTRATION Given to prevent **INH-induced peripheral neuropathy**: - **Mandatory in:** Pregnancy, PLHIV, DM, alcoholism, malnutrition, CKD, elderly - **Dose:** 25–50 mg/day orally --- ## 10. NTEP PROGRAM DELIVERY | Aspect | Details | |---|---| | **Platform** | Delivered through NikshaY portal tracking | | **DOT (Directly Observed Therapy)** | Mandatory for 3HP (weekly dosing); encouraged for all regimens | | **Nikshay Poshan Yojana** | Nutritional support ₹500/month for TB patients (extends to some TPT recipients) | | **Contact investigation** | Systematic tracing of all household/close contacts of index TB cases | | **Cascade** | Identify → Screen → Test (if needed) → Initiate TPT → Complete | --- ## 11. EFFICACY OF TPT REGIMENS | Regimen | Efficacy (TB prevention) | Completion Rate | |---|---|---| | 6H | ~60–90% | ~60–70% | | 9H | ~90% | ~60% | | 3HP | ~89% (non-inferior to 9H) | **~82–90%** (highest) | | 4R | ~80% | ~78% | | 3HR | Similar to 3HP | ~80% | > **3HP has the highest completion rates** — major advantage driving NTEP adoption --- ## 12. HIGH-YIELD EXAM POINTS (MD/PGMEE) | Point | Detail | |---|---| | TPT formerly called | IPT (Isoniazid Preventive Therapy) | | NTEP preferred regimen | **3HP** (3 months, weekly) | | INH dose in TPT | **5 mg/kg/day** (max 300 mg) | | TST required for PLHIV? | **No** — treat empirically after ruling out active TB | | Age below which all contacts get TPT | **< 5 years** — all get TPT regardless of TST | | Pyridoxine dose | **25–50 mg/day** with INH | | Ruling out active TB tool | **W4SS (4-symptom screen)** | | Most common side effect of INH | **Hepatotoxicity** | | TPT in MDR contact | **No standard regimen; fluoroquinolone-based** under study | | TPT in pregnancy | Defer if possible; if PLHIV, use **6H + pyridoxine** | | Duration of standard IPT | 6 months (6H) | | WHO 2020 new short regimen | **1HP** (1 month daily INH + Rifapentine) — conditional | | End TB strategy pillar | TPT is part of **Pillar 1: Integrated TB care and prevention** | --- ## 13. CLASSIFICATION SUMMARY TABLE | Regimen | Drugs | Duration | Frequency | WHO Grade | |---|---|---|---|---| | **6H** | INH | 6 months | Daily | Strong | | **9H** | INH | 9 months | Daily | Strong | | **3HP** | INH + Rifapentine | 3 months | Weekly | Strong | | **3HR** | INH + RIF | 3 months | Daily | Strong | | **4R** | RIF | 4 months | Daily | Strong | | **1HP** | INH + Rifapentine | 1 month | Daily | Conditional | --- What is difference between this answer and your answer which can fetch me more marks

Here's a direct, honest comparison — what each answer has, what's missing, and what gets you more marks in MD/PGMEE exams.

Head-to-Head Gap Analysis

✅ What the "Comprehensive Exam Answer" (above) has that MINE lacked

Item	Exam Relevance	Why it matters
W4SS (4-symptom screen) for ruling out active TB	⭐⭐⭐ High	Direct 1-mark MCQ trap — "which tool to rule out active TB before TPT?"
9H regimen explicitly listed	⭐⭐ Medium	WHO still recommends 9H for PLHIV; my answer skipped it
3HR (3 months INH + Rifampicin daily) as a regimen	⭐⭐ Medium	Used when rifapentine unavailable — appears in WHO tables
Primary vs Secondary prophylaxis distinction	⭐⭐ Medium	Classic exam definition question
MDR-TB contacts — no standard TPT, fluoroquinolone-based under study	⭐⭐⭐ High	Repeated PG exam topic; "what TPT for MDR contact?"
Rifapentine weight-based dosing table (5 weight bands for 3HP)	⭐⭐ Medium	More granular than my table
Category A vs Category B priority group classification	⭐⭐ Medium	Organizational framework examiners like
Nikshay portal / Nikshay Poshan Yojana	⭐ Low-Medium	Program delivery context; community medicine angle
TPT as End TB Strategy Pillar 1	⭐⭐ Medium	"TPT is part of which pillar?" — MCQ
WHO Grade (Strong vs Conditional) per regimen	⭐⭐ Medium	Examiners test which regimens are "strongly" vs "conditionally" recommended
Efficacy table (% TB prevention per regimen)	⭐⭐⭐ High	9H ~90% efficacy is a favourite MCQ fact
Pregnancy: defer unless PLHIV rule	⭐⭐⭐ High	My answer said "not known" for 3HP in pregnancy — that answer correctly says defer, use 6H
INH-induced hepatitis history = contraindication	⭐⭐ Medium	I listed hepatitis but not specifically prior INH hepatitis

✅ What MY answer has that the "Comprehensive" answer lacks or gets wrong

Item	Exam Relevance	Notes
Cy-Tb skin test (GOI approved Aug 2023) — ESAT-6/CFP-10, universal 5 mm cut-off, field-friendly	⭐⭐⭐ Very High	This is NEW and directly from your PDF/GOI circular. The other answer has zero mention of Cy-Tb — this is a current affairs MCQ
1HP dosing specifics: INH 300 mg + RPT 600 mg daily (fixed, not weight-based)	⭐⭐ Medium	The other answer doesn't give 1HP dosing
ART drug-by-drug compatibility table (PIs/NVP/TAF = contraindicated; TDF/EFV/DTG/RAL = safe)	⭐⭐⭐ High	The other answer says only "dose adjustment may be needed" — my answer is more precise for PLHIV on ART
NTEP treatment completion criteria (144/180 doses within 239 days for 6H; 11/12 doses for 3HP)	⭐⭐ Medium	Programme exam topic; the other answer has no completion thresholds
Contraception interaction with rifamycins (shorten DMPA to 8 weeks, implant to 8 weeks)	⭐⭐ Medium	Not mentioned in the other answer at all
6Lfx (levofloxacin for DR-TB contacts) listed as a regimen with dosing/completion criteria	⭐⭐⭐ High	The other answer says "no standard regimen yet" — but NTEP 2021 guidelines do include 6Lfx
Pyridoxine dose stratified: 10 mg (children), 25 mg (adults), 50 mg (PLHIV)	⭐⭐ Medium	The other answer gives only "25–50 mg" — less precise
Textbook citations + PMID-linked evidence	Academic depth	Useful for written/long-answer exams

❌ What NEITHER answer covers well (mark-fetching additions)

Missing Item	Marks Potential
TST cut-offs: ≥5 mm (PLHIV, close contacts), ≥10 mm (general high-risk), ≥15 mm (low-risk)	MCQ staple
Booster phenomenon in TST and why IGRA avoids it	Short note topic
IGRA types: QuantiFERON-TB Gold Plus, T-SPOT.TB — what they measure (IFN-γ)	Asked in immunology-linked questions
Serial testing strategy: when to repeat TST at 8–10 weeks if initially negative (window period)	Clinical scenario MCQ
36-month INH in PLHIV (WHO conditional recommendation in high-burden settings)	"What is the extended TPT duration in PLHIV?"
Cascade of care metrics NTEP tracks: tested → eligible → initiated → completed	Programme exam

Bottom Line — What Gets You More Marks

Use the "Comprehensive" answer's structure (W4SS, primary/secondary, Category A/B, efficacy %, WHO grades, MDR contact management) combined with my answer's specifics (Cy-Tb test, ART compatibility table, 6Lfx, completion criteria, contraception interaction, stratified pyridoxine doses).

The single biggest mark-fetcher neither answer covers fully:

Cy-Tb + W4SS + 6Lfx for MDR contacts + ART compatibility (drug-by-drug) + 36-month INH in PLHIV

These five points appear in recent NTEP/GOI documents and are high-yield precisely because most standard textbooks don't cover them yet — making them favourite "current affairs" exam questions at the MD/DNB level.

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