Vaccine-Preventable Diseases and Adult Immunisation

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The one-minute consultant answer

Adult immunisation in the physician context is not the protocol-driven GP encounter — it is a clinical-reasoning task applied to the patient whose comorbidity, immunosuppression, pregnancy, asplenia, or travel plans modify the standard schedule in ways that the schedule alone cannot resolve. The physician is the doctor who sees the patient before rituximab, before anti-TNF, before transplant, before splenectomy, before international travel, and in pregnancy — the moments where the question is not "what vaccines are due?" but "what can I safely give, in what order, and by when, before the window for a useful vaccine response closes?" [1]

The central principle is: vaccinate before immunosuppression begins, because the vaccine response depends on a functional immune system [1]. Give inactivated vaccines at least 2 weeks before immunosuppression (ideally 4) and live vaccines at least 4 weeks before — because B-cell-depleting therapy like rituximab renders vaccines ineffective for 6 to 12 months, and the patient on chemotherapy or post-transplant immunosuppression cannot mount the antibody response that the vaccine requires.

The second principle is the live-versus-inactivated distinction, which governs every immunisation decision in immunocompromise. Live vaccines — MMR, varicella, yellow fever, BCG, oral polio (OPV), oral typhoid (Ty21a), live attenuated influenza (intranasal), and rotavirus — replicate in the host and can cause disseminated disease in severe immunosuppression. They are contraindicated in the severely immunosuppressed (high-dose corticosteroids above 20 mg prednisolone for more than 2 weeks, chemotherapy, transplant immunosuppression, anti-CD20 therapy, HIV with CD4 below 200), and the safe inactivated alternative must be used instead. The one exception with nuance is HIV: MMR and varicella are safe if the CD4 is above 200 and the patient is clinically stable, but yellow fever is still avoided [1].

The third principle is the sequential pneumococcal schedule: give the conjugate vaccine (PCV13, PCV15, or PCV20) first because it primes T-cell-dependent immunological memory, then the polysaccharide (PPSV23) at least 8 weeks later to broaden serotype coverage — or simply give PCV20 alone, which has superseded the two-dose schedule in the 2024 ACIP guidance. The CAPiTA trial demonstrated that PCV13 prevents vaccine-type community-acquired pneumonia (45.6 per cent efficacy) and invasive pneumococcal disease (75 per cent efficacy) in adults aged 65 and older [2].

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1. [1]Rubin LG, Levin MJ, Ljungman P, et al. 2013 IDSA clinical practice guideline for vaccination of the immunocompromised host Clin Infect Dis, 2014.PMID 24421306
2. [2]Bonten MJM, Huijts SM, Bolkenbaas M, et al. Polysaccharide conjugate vaccine against pneumococcal pneumonia in adults N Engl J Med, 2015.PMID 25785969
3. [3]Cunningham AL, Lal H, Kovac M, et al. Efficacy of the Herpes Zoster Subunit Vaccine in Adults 70 Years of Age or Older N Engl J Med, 2016.PMID 27626517
4. [4]Amirthalingam G, Andrews N, Campbell H, et al. Effectiveness of maternal pertussis vaccination in England: an observational study Lancet, 2014.PMID 25037990
5. [5]Joura EA, Giuliano AR, Iversen OE, et al. A 9-valent HPV vaccine against infection and intraepithelial neoplasia in women N Engl J Med, 2015.PMID 25693011
6. [6]Haber P, DeStefano F, Angulo FJ, et al. Guillain-Barré syndrome following influenza vaccination JAMA, 2004.PMID 15562126
7. [7]CDC Use of 13-valent pneumococcal conjugate vaccine and 23-valent pneumococcal polysaccharide vaccine for adults with immunocompromising conditions: recommendations of the Advisory Committee on Immunization Practices (ACIP) MMWR Morb Mortal Wkly Rep, 2012.PMID 23051612
8. [8]Lal H, Cunningham AL, Godeaux O, et al. Efficacy of an adjuvanted herpes zoster subunit vaccine in older adults N Engl J Med, 2015.PMID 25916341