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Medical Microbiology Exercises - Complete Answers

Exercise MI 2.7.3 - HIV (Pages 1-2)

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Q1. Identify and interpret the given serological test done for this patient

• The card shows labeled positions for HIV-1 and HIV-2
• Two dots are visible (control dot + reactive dot), indicating a positive/reactive result
• This is a point-of-care rapid antibody detection test using recombinant HIV antigens
• Interpretation: Reactive for HIV antibodies - consistent with HIV infection

• The orange/yellow colored wells (rows A-D, columns 1-7 approximately) indicate optical density above the cut-off = reactive wells
• Colorless wells = non-reactive
• The pattern seen is consistent with an indirect or sandwich ELISA for anti-HIV antibodies
• Interpretation: ELISA positive for HIV antibodies

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Q2. What are the various modes of transmission of the etiological agent (HIV)?

• Unprotected heterosexual or homosexual intercourse
• Receptive anal intercourse carries the highest per-act risk
• Vaginal intercourse (bidirectional, female-to-male and male-to-female)
• Oral sex (low but non-zero risk)

• Sharing contaminated intravenous drug needles/syringes
• Blood transfusions or blood products (screened in most countries now)
• Needlestick injuries in healthcare workers
• Transplantation of infected organs or tissue

• In utero (transplacental) - especially in third trimester
• Intrapartum (during delivery) - most common
• Postpartum - through breastfeeding

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Q3. What are the different modalities of diagnosis of this clinical condition?

• ELISA (3rd/4th generation): Detects anti-HIV IgG/IgM antibodies (window period: 3-6 weeks for 4th gen)
• Rapid tests / TRI-DOT / ICT: Point-of-care lateral flow assays
• Western Blot: Confirmatory gold standard - detects antibodies to specific viral proteins (gp41, gp120, gp160, p24, p31, p51, p66)
• Line Immunoassay (LIA): Alternative confirmatory test

• p24 antigen ELISA: Detects viral core antigen; positive before antibody (during acute infection window period)
• 4th generation combo ELISA: Detects both p24 Ag and anti-HIV antibodies simultaneously

• HIV RNA PCR (Viral Load): Quantitative; used for monitoring treatment response and in neonates
• HIV DNA PCR: Detects proviral DNA; used in infants born to HIV-positive mothers
• NAAT (Nucleic Acid Amplification Test): Used for early diagnosis during window period

• Not diagnostic but essential for staging and treatment decisions
• Normal: 500-1500 cells/µL; AIDS defined as <200 cells/µL or AIDS-defining illness

• Uses three rapid tests (Strategy III) for diagnosis in symptomatic individuals

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Q4. Which are the various opportunistic infections that can occur in this patient?

• Respiratory: PCP (Pneumocystis jirovecii), TB, Aspergillosis
• GI: Cryptosporidiosis, Isospora, Microsporidiosis, CMV colitis, Candida esophagitis
• CNS: Toxoplasmic encephalitis, Cryptococcal meningitis, PML (JC virus), HIV encephalopathy
• Skin: Herpes zoster, Kaposi's sarcoma (HHV-8), Molluscum contagiosum
• Ocular: CMV retinitis
• Systemic: Disseminated MAC, Histoplasmosis, Penicilliosis

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Q5. How will you treat this condition?

• Tenofovir (TDF) + Lamivudine (3TC) + Dolutegravir (DTG)
• TDF 300 mg + 3TC 300 mg + DTG 50 mg once daily (single-tablet regimen)

• NRTIs (Nucleoside Reverse Transcriptase Inhibitors): TDF, 3TC, Zidovudine (AZT), Emtricitabine (FTC), Abacavir
• NNRTIs (Non-Nucleoside RTIs): Efavirenz, Nevirapine, Rilpivirine
• Integrase Strand Transfer Inhibitors (INSTIs): Dolutegravir, Raltegravir, Bictegravir
• Protease Inhibitors (PIs): Lopinavir/ritonavir, Atazanavir/ritonavir
• Entry/Fusion Inhibitors: Maraviroc (CCR5 antagonist), Enfuvirtide

• CD4 <200: Co-trimoxazole (TMP-SMX) for PCP + toxoplasmosis prophylaxis
• Fluconazole for cryptococcal prophylaxis in high-burden settings
• INH prophylaxis therapy (IPT) for TB

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Q6. Discuss confidentiality pertaining to patient identity in laboratory results

• Informed consent must be obtained before testing (except in specific exceptions like blood donation screening, PPTCT programs)
• Results must be disclosed only to the patient and authorized healthcare providers directly involved in care
• Results must not be disclosed to employers, insurance companies, family members (without patient consent), or other institutions
• Lab reports should use coded identifiers - patient's name should not appear on HIV result reports in India
• Under the HIV and AIDS (Prevention and Control) Act, 2017 (India): unauthorized disclosure of HIV status is a punishable offense
• Exceptions where disclosure is permitted: to protect a third party at risk (e.g., sexual partner), with patient's written consent, or by court order
• Pre-test and post-test counseling is mandatory (ICTC - Integrated Counseling and Testing Centre)
• The "need to know" principle applies - only those directly involved in treatment need the information

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Q7. What is NACO Strategy I and where is it applied?

• Uses a single ELISA or rapid test
• A specimen is reported positive if the single test is reactive
• A specimen is reported negative if the single test is non-reactive

• Used exclusively for blood/organ/semen donor screening (transfusion safety)
• The goal is maximum sensitivity - no blood unit that is HIV-positive should be missed
• Not used for diagnostic purposes in symptomatic individuals
• Donors testing positive are deferred from donation; the blood unit is discarded

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Q8. What is NACO Strategy II and where is it applied?

• Uses two different ELISA/rapid tests with different antigen preparations or formats
• If Test 1 is reactive: perform Test 2
  • If Test 2 also reactive → Report as HIV positive
  • If Test 2 is non-reactive → perform Test 3 (the "tie-breaker")
• If Test 1 is non-reactive: Report as HIV negative

• Used for surveillance purposes (sentinel surveillance, epidemiological studies)
• Low-prevalence settings
• Not for individual patient diagnosis

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Q9. What is NACO Strategy III and where is it applied?

• Uses three different tests (ideally using different antigens/formats - one ELISA + two rapid tests OR three rapid tests)
• Algorithm:
  • Test 1 (most sensitive): If non-reactive → Report HIV negative
  • If Test 1 reactive → Test 2: If reactive → Test 3
  • If Test 3 reactive → Report HIV positive
  • If any discordance between Test 2 and Test 3 → Report as indeterminate - repeat after 2-4 weeks

• Mandatory for diagnosis and clinical management of symptomatic and asymptomatic individuals
• All ICTCs (Integrated Counseling and Testing Centres) use this
• HIV-positive pregnant women (PPTCT program)
• Any individual presenting with clinical features suggestive of HIV/AIDS
• This is the strategy used in this clinical case

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Exercise MI3.7 AE - Hepatitis B (Pages 3-4)

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Q1. Based on the test provided, what is your diagnosis?

• Positive HBsAg (marker of active HBV infection/carrier)
• Clinical features: jaundice (elevated bilirubin), hepatitis (elevated liver enzymes)
• History of multiple blood transfusions (risk factor for HBV)
• Acute presentation (10-day history)

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Q2. Suggest a test to know the infectiousness of the patient

• HBeAg positivity indicates active viral replication and high infectiousness
• Derived from the precore/core region of HBV genome
• Patients with HBeAg+ are 5-10 times more infectious than HBeAg-negative patients

• The most direct and quantitative measure of infectiousness
• Levels >20,000 IU/mL in HBeAg+ chronic hepatitis B indicate high replication
• "Gold standard" for assessing infectiousness and treatment monitoring

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Q3. Suggest a test to know if the infection is acute or chronic

• A high-titer anti-HBc IgM = Acute HBV infection (marker of recent infection)
• Persists for 6-12 months after acute infection
• In chronic HBV: anti-HBc IgG is present (total anti-HBc positive, IgM negative or very low)

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Q4. Enumerate the modes of transmission of this infection

• Blood transfusions (most common in this case - multiple transfusions)
• Sharing contaminated needles (IV drug users)
• Needlestick injuries (healthcare workers - occupational risk)
• Tattooing, body piercing with unsterilized equipment
• Sharing razors, toothbrushes

• Unprotected sexual contact (heterosexual and homosexual)
• HBsAg present in semen, vaginal secretions, saliva

• Perinatal transmission during delivery (most important route in endemic regions like Asia)
• In utero (rare, ~2-3% of cases)
• Breastfeeding (low risk, not a contraindication if infant vaccinated)

• Within households, particularly when sharing personal items
• HBV can survive on environmental surfaces for >7 days

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Q5. How is the general prognosis of this condition?

• ~95% of immunocompetent adults recover completely with clearance of HBsAg and development of protective anti-HBs
• ~0.1-0.5% develop fulminant hepatic failure (higher risk with co-infection with HDV)
• ~5% progress to chronic infection (adults)
• Neonates and infants: ~90% become chronically infected

• ~15-40% develop serious complications over 5 years
• Cirrhosis: ~20-30% of chronic HBV patients
• Hepatocellular carcinoma (HCC): 100-fold increased risk; 15-40% of HCC worldwide is HBV-related
• Liver failure: End-stage complication

• Co-infection with HIV, HCV, or HDV
• Alcohol consumption
• HBeAg positivity (indicates ongoing replication)
• High HBV DNA levels

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Q6. Describe briefly the preventive measures of this condition

• Recombinant HBV vaccine (HBsAg produced in yeast - Saccharomyces cerevisiae)
• Schedule: 0, 1, 6 months (3-dose) OR 0, 1, 2, 12 months (4-dose accelerated)
• Included in Universal Immunization Programme (UIP) of India: Birth dose + at 6, 10, 14 weeks (pentavalent vaccine)
• Efficacy: >90% in immunocompetent adults; check anti-HBs titer 1-3 months post-vaccination

• Hepatitis B Immunoglobulin (HBIG): Given within 24-48 hours after exposure (post-exposure prophylaxis), also to neonates of HBsAg-positive mothers at birth

• Mandatory HBsAg screening of all donated blood
• Nucleic Acid Testing (NAT) to reduce window period donations

• Use of gloves, safe injection practices, proper needle disposal
• Sterilization of medical/surgical instruments

• Safe sex practices (condoms)
• Avoid sharing needles, razors, toothbrushes
• Safe tattooing/piercing practices

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Q7. Interpretation of serological markers table:

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Exercise 19.2 - Rotavirus (Pages 5-6)

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Q1. Identify the most probable pathogen in this case

• The electron micrograph shows classic wheel-shaped (rota = wheel in Latin) double-capsid particles, ~70nm in diameter with distinct spokes radiating from a hub
• This is the most common cause of severe dehydrating gastroenteritis in children under 5 years worldwide
• Clinical features: abrupt onset, vomiting preceding diarrhea, watery (non-bloody) diarrhea, fever - classic rotavirus pattern
• Peak age: 6 months to 2 years
• Rotavirus is a double-stranded RNA virus with 11 segments enclosed in a triple-layered protein capsid

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Q2. Name other tests to confirm the laboratory diagnosis

• ELISA for rotavirus antigen in stool (most common clinical test) - detects group A VP6 antigen
• Latex agglutination test - rapid, widely used
• Rapid immunochromatographic tests (ICT/card tests) - point of care

• RT-PCR - gold standard for genotyping (G and P types); detects all groups
• Polyacrylamide gel electrophoresis (PAGE) - shows characteristic "electropherotype" (11-band pattern with 4-2-3-2 grouping)

• Electron microscopy (as shown) - morphologically diagnostic but not routine
• Immune electron microscopy (IEM)

• Possible but technically demanding; not routine

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Q3. Name the other organisms causing similar clinical manifestations (watery diarrhea with vomiting in children)

• Norovirus (Calicivirus) - most common cause in older children and adults; outbreaks
• Enteric Adenovirus (types 40, 41) - second most common viral cause in children
• Astrovirus - watery diarrhea, milder
• Sapovirus - less common calicivirus

• Vibrio cholerae - "rice-water" stools, profuse watery diarrhea
• Enterotoxigenic E. coli (ETEC) - traveler's diarrhea, watery
• Cryptosporidium parvum - watery diarrhea in immunocompromised
• Giardia lamblia - chronic watery/fatty diarrhea

• Cryptosporidium parvum
• Giardia intestinalis

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Q4. List the laboratory tests to differentiate other pathogens causing this condition

• Macroscopy: color, consistency, blood/mucus
• Microscopy: pus cells, RBCs, parasites
• Culture: for bacterial pathogens
• Electron microscopy: for viral particles

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Q5. Describe briefly specific preventive measures for this condition

• Rotarix (GSK): Human rotavirus G1P[8] strain; 2-dose oral schedule (6 and 10 weeks)
• RotaTeq (Merck): Pentavalent human-bovine reassortant; 3-dose oral schedule (2, 4, 6 months)

• ROTAVAC (Bharat Biotech): Monovalent neonatal strain 116E; 3 doses at 6, 10, 14 weeks
• ROTASIIL (Serum Institute): Pentavalent bovine-human reassortant
• Introduced into Universal Immunization Programme (UIP) of India in 2016

• Exclusive breastfeeding in infancy (provides some passive protection via IgA)
• Hand hygiene with soap and water (alcohol-based sanitizers less effective against rotavirus)
• Safe water and food hygiene
• Proper disposal of diarrheal stools
• ORS (Oral Rehydration Solution) for management - reduces mortality but not specific prevention

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Q6. A local doctor has prescribed Syp. Amoxycillin-clavulanic acid in appropriate dose and frequency for 3 days. Is it justified?

1. Rotavirus is a virus - antibiotics have no action against viruses
2. Amoxicillin-clavulanic acid is an antibiotic (broad-spectrum penicillin + beta-lactamase inhibitor) - it acts on bacterial cell wall synthesis and is completely ineffective against viral gastroenteritis
3. Prescribing antibiotics for viral diarrhea contributes to antimicrobial resistance (AMR) - a major global health concern
4. Antibiotics may disrupt the intestinal microbiome, potentially prolonging diarrhea
5. This represents irrational antibiotic use / antibiotic stewardship failure

• ORS (Oral Rehydration Solution) - cornerstone of treatment; prevents dehydration
• Zinc supplementation (20 mg/day x 14 days for children >6 months) - reduces duration and severity, as per WHO/UNICEF guidelines
• Continued feeding - do not withhold feeds
• IV fluids only if signs of severe dehydration or failure of oral rehydration
• Antipyretics (paracetamol) for fever
• Antibiotics are indicated only if there is evidence of bacterial co-infection (blood in stool, high fever, elevated WBC with left shift)

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Exercise MI5.2.8 AE - Rabies (Pages 7-8)

• Left image: Neurons with pink cytoplasmic inclusions = Negri bodies (classic)
• Right image: Perivascular lymphocytic cuffing and neuronal degeneration = Encephalitis

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Q1. What is the diagnosis of this condition?

• History of dog bite (classic exposure)
• 15-day incubation period (range: 2 weeks to 1 year; average 1-3 months; shorter for head/neck bites)
• Prodromal phase: fever, headache, paresthesia at bite site
• Neurological phase (furious type): hydrophobia (cardinal symptom), aerophobia, anxiety, confusion, hallucinations, agitation
• Histopathology: Negri bodies (eosinophilic intracytoplasmic inclusions in neurons, especially Purkinje cells of cerebellum and hippocampal neurons of Ammon's horn)
• Fatal outcome without timely post-exposure prophylaxis

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Q2. Describe the lab diagnosis of the above condition

• Direct Fluorescent Antibody Test (dFAT/FAT): Nuchal skin biopsy (nape of neck, hair follicles contain corneal nerve endings); most reliable antemortem test
• Saliva RT-PCR: Detects rabies virus RNA; highly sensitive
• Corneal impression smear + FAT: Corneal cells examined for viral antigen
• CSF analysis: Mild pleocytosis, elevated protein; FAT on CSF for antigen
• Serum and CSF antibody neutralization tests (Rapid Fluorescent Focus Inhibition Test - RFFIT)

• Demonstration of Negri bodies: H&E stained brain sections (hippocampus, cerebellum)
  • Sellar's stain: Negri bodies appear magenta/pink against blue background
  • Negri bodies: eosinophilic, round/oval intracytoplasmic inclusions, 2-10 µm
  • Specificity ~100%, but sensitivity ~80% (absent in ~20% of rabies cases)
• Direct FAT on brain tissue: Gold standard postmortem test (WHO recommended)
• Mouse inoculation test (MIT): Brain suspension injected into mouse footpad/intracerebrally - mice develop paralysis + Negri bodies; slower (2-3 weeks)
• RT-PCR on brain tissue
• Virus isolation in cell culture (BHK-21, MRC-5 cells)

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Q3. What is the pre and post exposure prophylaxis?

• Indicated for: veterinarians, animal handlers, lab workers, forest workers, travelers to endemic areas
• Schedule: 3 doses of cell culture vaccine (CCV) on Days 0, 7, 21 (or 28)
• Route: Intramuscular (1 mL) in deltoid OR intradermal (0.1 mL)
• Booster doses: Every 2 years for high-risk groups (or check neutralizing antibody titer)
• No immunoglobulin needed for pre-exposure prophylaxis

• Wash wound thoroughly with soap and water for minimum 15 minutes
• Apply 70% ethanol, povidone-iodine, or quaternary ammonium compounds
• Do NOT suture primarily if possible (or minimal suturing)
• Tetanus prophylaxis

• Human Rabies Immunoglobulin (HRIG): 20 IU/kg body weight - inject as much as possible into and around the wound; remainder IM at distant site
• Equine RIG (ERIG): 40 IU/kg (requires skin test first; risk of serum sickness)
• Passive immunity provides immediate protection
• Given only for Category III exposures (WHO)

• Essen regimen (IM): Days 0, 3, 7, 14, 28 - 5 doses, 1 mL each IM in deltoid
• Zagreb regimen (IM): Days 0 (2 sites), 7, 21 - 4 doses total
• Updated Thai Red Cross Intradermal (TRC-ID) regimen: 0.1 mL ID at 2 sites on Days 0, 3, 7, 28
• Previously vaccinated individuals: Only 2 doses (Days 0 and 3), no RIG needed

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Q4. What is a cell culture vaccine?

• Produced by growing rabies virus in cell cultures (not in neural tissue)
• Types available:
  • HDCV (Human Diploid Cell Vaccine): Grown in WI-38 or MRC-5 human diploid cells; gold standard; expensive
  • PCECV (Purified Chick Embryo Cell Vaccine): Grown in primary chick embryo cells; e.g., Rabipur/RabAvert
  • PVRV (Purified Vero cell rabies vaccine): Grown in Vero (African green monkey kidney) cells; e.g., Verorab, Abhayrab
  • PDEV (Purified Duck Embryo Vaccine): Less used now

• More immunogenic
• Better safety profile (no risk of post-vaccinial encephalomyelitis/AEFI from myelin proteins)
• Purer preparation
• Standardized potency (≥2.5 IU/dose)

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Q5. What is a subunit vaccine?

• Protein subunit: Purified specific proteins (e.g., HBsAg in Hepatitis B vaccine - recombinant subunit)
• Polysaccharide: Purified capsular polysaccharides (e.g., pneumococcal polysaccharide vaccine)
• Conjugate: Polysaccharide linked to a carrier protein to enhance immunogenicity (e.g., Hib vaccine, meningococcal conjugate)
• Recombinant: Antigen produced by recombinant DNA technology in yeast/bacteria/mammalian cells
• Virus-like particles (VLPs): Self-assembling protein shells without nucleic acid (e.g., HPV vaccine - Gardasil/Cervarix)

• Safe (no live pathogen; no risk of reversion)
• Stable
• Can be used in immunocompromised patients

• Less immunogenic (often require adjuvants and multiple doses)
• May not generate cellular immunity as effectively as live attenuated vaccines

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Q6. Which vaccine is available in India? What is the dosage?

• Berirab-P (HRIG): 20 IU/kg
• Abhayrab HIG / Kamrab: Human RIG
• Equine RIG (ERIG): 40 IU/kg; cheaper; test for sensitivity first

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Q7. How do you differentiate a case of encephalitis from meningitis?

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Q8. A slide has been focused related to this disease - identify and draw a labeled diagram

• Large neurons visible with distinct nucleus and nucleolus
• In the cytoplasm: oval/round, eosinophilic (pink), sharply defined inclusions
• Size: 2-10 µm diameter
• Location: Preferentially in Purkinje cells of cerebellum and pyramidal neurons of hippocampus (Ammon's horn)
• Composition: Contain aggregates of rabies virus nucleocapsid proteins (N protein + RNA)
• Stain: Eosinophilic on H&E; magenta on Seller's stain
• Pathognomonic of rabies (diagnostic specificity ~100%)

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Exercise MI8.1.3 - Dengue (Pages 9-10)

1. Dengue NS1 rapid card test (labeled "DENGUE NS1 Ag") - showing positive band
2. Dengue NS1Ag ELISA plate - showing reactive wells (yellow/orange) in the first few columns

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Q1. What is the clinical diagnosis and how you arrived at it?

• Classic Dengue Triad: High fever + severe headache + myalgia
• Retro-orbital pain: Highly characteristic (pain behind the eyes, worsens on eye movement)
• "Breakbone fever": Severe myalgia especially of lower back, arms, legs - classic dengue description
• Thrombocytopenia: <1 Lac/µL (normal: 1.5-4.5 Lac/µL) - hallmark of dengue
• NS1 antigen test positive: Dengue NS1 (Non-Structural protein 1) is detectable in blood during Days 1-9 of fever
• ELISA for NS1 positive: High sensitivity for dengue in early febrile phase

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Q2. Explain the mode of transmission of this disease

• Primary vector: Aedes aegypti (black/white striped mosquito; day-biting; breeds in clean stagnant water)
• Secondary vector: Aedes albopictus (tiger mosquito)

1. Mosquito bites viremic dengue patient (Day 1-5 of fever = peak viremia)
2. Virus replicates in mosquito midgut → salivary glands (extrinsic incubation period: 8-12 days)
3. Infected mosquito bites susceptible human → transmission via saliva
4. Transovarial transmission in mosquito possible (virus passed to eggs)

• Person-to-person contact
• Through air/water
• (Blood transfusion and needle-stick: rare but documented)

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Q3. Interpret the results of the laboratory test displayed

• Shows control line (C) and test line (T) visible = POSITIVE for Dengue NS1 Antigen
• Interpretation: Active dengue infection (viremic phase, Days 1-9)

• Yellow/orange colored wells in the first 3-4 rows (samples) with a red/high optical density = Reactive = NS1 Antigen positive
• The pale wells = negative controls/low samples
• Interpretation: ELISA confirms NS1 antigen positivity - consistent with active dengue viremia

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Q4. Suggest other microbiological tests for diagnosis of this condition

• NS1 antigen detection: ELISA or rapid card test (as shown; sensitivity ~80-90% in early phase)
• Virus isolation: Aedes albopictus C6/36 cell line or Vero cells (gold standard but slow, specialized labs)
• RT-PCR for dengue RNA: Most sensitive; allows serotyping; useful Days 1-7; reference labs

• IgM ELISA: Detects dengue-specific IgM; appears Day 3-5; persists for months - gold standard serological test
• IgG ELISA: Appears Day 7-10; high levels suggest secondary infection; persists for years
• NS1+IgM+IgG combo rapid tests: Cover both early and late phase
• MAC-ELISA (IgM Antibody Capture ELISA): WHO recommended for routine diagnosis
• Haemagglutination Inhibition (HAI) test: 4-fold rise in paired sera = significant
• Plaque Reduction Neutralization Test (PRNT): Gold standard serological confirmation; serotype-specific; reference labs only

• CBC (thrombocytopenia, leukopenia, rising hematocrit in DHF)
• Liver function tests (transaminases elevated)
• Coagulation profile if suspected DHF

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Q5. Suggest treatment for this condition

• Adequate hydration: Oral fluids (ORS, coconut water, juices) - 2-3 L/day
• Antipyretics: Paracetamol (acetaminophen) - do NOT use aspirin, ibuprofen, or other NSAIDs (risk of bleeding, Reye's syndrome; NSAIDs reduce platelet function)
• Rest
• Monitor: Daily CBC for platelet count and hematocrit
• Watch for warning signs: Abdominal pain, persistent vomiting, bleeding, fluid accumulation, rapid clinical deterioration

• IV fluid therapy - careful fluid management to prevent plasma leakage complications
  • Isotonic crystalloids (Ringer's lactate / NS 0.9%)
  • Rate based on clinical status and hematocrit
• Platelet transfusion: Only if <10,000/µL or active significant bleeding (not routinely for thrombocytopenia alone)
• Blood transfusion: For severe bleeding with anemia
• Monitoring: Hourly urine output, vital signs, serial hematocrit
• ICU care for dengue shock syndrome (DSS)

• Dengvaxia (CYD-TDV, Sanofi Pasteur): First licensed dengue vaccine; tetravalent; approved in some countries for seropositive individuals aged 9-45 in endemic areas; NOT recommended for seronegative individuals (risk of severe dengue on first natural infection)
• Qdenga (TAK-003, Takeda): Newer; approved in multiple countries including EU/Indonesia; 2-dose schedule

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