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#vaccine administration

2 public questions tagged with this topic.

Vaccine

BCG vaccine is administered via:

BCG vaccine is administered via intradermal route which is uniquely specified among routine childhood immunizations. Technique involves injection of small volume 0.05 ml for infants under 12 months and 0.1 ml for older children into superficial dermis of lower insertion of deltoid muscle left arm using 26G or 27G needle inserted bevel upward at approximately 10-15 degree angle pushing needle 2 mm subepidermal creating characteristic peau d orange wheal 6-8 mm bleb that disappears within 30 minutes indicating correct placement. Dermis abundant in Langerhans cells expressing langerin CD207 and dermal CD14+ dendritic cells highly efficient capturing mycobacterial antigens Ag85 complex, migrating to axillary lymph nodes priming Th1 cells secreting interferon gamma activating macrophages forming granuloma containment. Intramuscular or subcutaneous misadministration risks cold abscess formation caseous necrosis, suppurative lymphadenitis, dissemination in immunocompromised and absence of scar considered marker of take. Intradermal route ensures slow depot release, localized induration 2-3 weeks later forming papule ulceration healing with flat 3-7 mm scar visible for life. WHO recommends only intradermal, discouraging jet injectors; training with orange peel simulation and competency assessment mandatory to ensure high coverage scar rates above 90 percent monitoring program quality.

Ref: WHO BCG vaccine position paper 2018 intradermal; Plotkin BCG route; CDC intradermal.

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Vaccine

Edible vaccines should preferably be consumed:

Edible vaccines rely on oral exposure to gut associated lymphoid tissue, so preservation of antigen structural integrity is crucial. Cooking, drying at high temperature, roasting, fermentation involving microbial proteases and acidic boiling denatures protein tertiary structure, unfolding alpha helices and beta sheets, disrupting disulfide bonds essential for conformational B cell epitopes required for neutralizing antibody induction, aggregating proteins into insoluble forms, destroying T cell epitopes via hydrolysis. For example HBsAg virus like particles dissociate into monomers losing particulate presentation critical for B cell receptor crosslinking if heated above 60C. Maillard reaction between sugars and lysine alters antigenicity. Therefore transgenic expression targeted to raw edible tissues like banana fruit pulp eaten fresh peeled, tomato fruit consumed raw in salads, lettuce leaves, baby carrots, rice seeds eaten without extensive heating although rice normally cooked may retain some antigen if heat stable variants engineered. If cooking mandatory, alternative freeze-drying retaining structure followed by consumption as powder capsules or incorporation into chocolate considered. Guidance emphasizes consumption raw without processing after harvest with minimal refrigeration to maintain native conformation for maximal mucosal IgA and avoid tolerance.

Ref: Mason et al. 2002 Trends Biotech Edible consumption raw; Streatfield Kwon 2007 Should be raw.

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