Adult Immunisation Advisor

Evidence-Based Pearls & Pathophysiology

1. Practice Advisory: The Tetanus Toxoid (TT) Caution

Avoid Standalone TT: In India, there is a widespread unsafe practice of prescribing standalone Tetanus Toxoid (TT) for wound management or during pregnancy. Pathophysiology/Epidemiology: Due to waning adult immunity against Diphtheria (which relies on herd immunity), the Government of India officially replaced TT with Td (Tetanus & adult-dose Diphtheria) in the National Immunisation Schedule in 2019. You MUST prescribe Td or Tdap, never standalone TT.

2. Illness Script: Identifying Live Vaccines (Mnemonic)

Live attenuated vaccines carry a risk of uncontrolled viral or bacterial replication. They are strictly contraindicated in pregnant women (due to teratogenicity as pathogens cross the placenta) and severely immunocompromised patients.

Mnemonic: "Be A VIP, MMR!"
BCG
Adenovirus (oral)
Varicella
Influenza (LAIV - Intranasal only)
Polio (OPV - Oral)
Measles, Mumps, Rubella (MMR)
*Also includes Yellow Fever and Zoster (ZVL/Zostavax).

3. Why Adult Immunisation Matters in India

Immunosenescence: Age-related decline in innate and adaptive immune function increases susceptibility and mortality to influenza, pneumococcal disease, and herpes zoster in older adults.
Comorbidity Burden: India's rising prevalence of diabetes, CKD, and COPD creates massive cohorts of patients whose baseline mucosal immunity is impaired, requiring targeted vaccination.
AMR Stewardship: Viral vaccines (like Influenza) prevent secondary bacterial pneumonias, directly reducing unnecessary empirical broad-spectrum antibiotic prescriptions.

4. Pneumococcal Strategy: The PCV20 Shift

Avoid Simultaneous Administration Advisory: Never give PCV and PPSV23 at the same time. Simultaneous administration induces B-cell immune tolerance and blunts the antibody response.

API 2026 Shift: PCV20 is now the preferred single-dose pneumococcal vaccine. It covers 7 additional serotypes compared to PCV13, eliminating the need for the older, sequential PCV13 → (wait 1 year) → PPSV23 approach, which suffered from high drop-out rates and polysaccharide-induced hyporesponsiveness.

5. Herpes Zoster (Shingles) Vaccination

Vaccine Type	Pathophysiology & Recommendation
RZV (Shingrix) Recommended	Recombinant glycoprotein E antigen with AS01B adjuvant. Non-live. Highly immunogenic. Safe in immunocompromised patients. Recommended for ALL adults ≥50 years, and immunocompromised ≥18 years.
ZVL (Zostavax) Obsolete	Live-attenuated virus. Contraindicated in immunosuppression. Waning efficacy. No longer recommended by API or CDC.

6. Vaccination in Pregnancy

The goal is dual protection: protecting the mother from severe disease (e.g., Influenza) and providing passive transplacental IgG antibodies to the neonate (e.g., Pertussis).

Status	Vaccines
STRONGLY RECOMMENDED	Tdap: 27-36 weeks, in EACH pregnancy to maximise transplacental pertussis antibodies. Inactivated Influenza: Any trimester.
USE IF INDICATED	Hepatitis B (if at risk and unvaccinated); Pneumococcal.
CONTRAINDICATED	Live Vaccines (MMR, Varicella, LAIV, BCG, Yellow Fever). Wait at least 4 weeks after a live vaccine before conceiving. HPV is also deferred.

Abbreviations: API (Association of Physicians of India) · Td (Tetanus & adult Diphtheria) · Tdap (Tetanus, Diphtheria & acellular Pertussis) · IIV (Inactivated Influenza Vaccine) · LAIV (Live Attenuated Influenza Vaccine) · PCV (Pneumococcal Conjugate Vaccine) · PPSV23 (Pneumococcal Polysaccharide Vaccine) · RZV (Recombinant Zoster Vaccine) · ZVL (Zoster Vaccine Live) · HPV (Human Papillomavirus) · MMR (Measles, Mumps, Rubella) · HepA/B (Hepatitis A/B) · HCW (Healthcare Worker) · CKD (Chronic Kidney Disease) · CLD (Chronic Liver Disease) · COPD (Chronic Obstructive Pulmonary Disease) · CHF (Congestive Heart Failure) · DM (Diabetes Mellitus) · NIS (National Immunisation Schedule)

Adult Immunisation Advisor

1. Age Group

2. Biological Sex

3. Pregnant or Planning Pregnancy? ?

4. Comorbidities & Risk Factors ?