Chanjo ya Homa ya Q

Wafanyakazi wa ufugaji, madaktari wa wanyama, wafanyakazi wa machinjio, watafiti wa maabara wanaoshughulika na Coxiella burnetii.

Severe allergic reaction to previous dose or any component. Previous Q fever infection (confirmed or suspected) — vaccination of previously immune individuals can cause severe local reactions including sterile abscess, granuloma. Positive Q fever skin test (Coxiella Skin Test, CST ≥5 mm). Positive Q fever serology (IgG Phase I or Phase II ≥1:10). Pregnancy (insufficient data). Immunocompromised individuals (limited efficacy data).

Common (1–10%): injection site pain (40–50%), induration, erythema, headache, malaise, myalgia, fatigue. Uncommon: fever, lymphadenopathy. Rare but important: severe local reactions in pre-sensitized individuals (if screening omitted) — sterile abscess, granuloma at injection site. Chronic fatigue syndrome (Q fever fatigue syndrome, QFS): debated association, Australian studies suggest no increased risk with proper pre-screening.

Single 0.5 mL dose, subcutaneous injection (deltoid region). No booster recommended — single dose provides long-term immunity (≥5 years confirmed, likely lifetime). Must complete pre-vaccination screening 7 days before vaccination. Administer ≥14 days before potential exposure. Currently only available in Australia (special access in other countries).

Pre-licensure study (Marmion et al.): 100% efficacy in seronegative abattoir workers over 15 months. Australian post-marketing surveillance: vaccine effectiveness ~95–100% in occupational cohorts with >20 years follow-up. Single dose generates durable cell-mediated and humoral immunity. Seroconversion: >97% at 28 days post-vaccination.

Store at +2°C to +8°C. Do not freeze. Protect from light. Use within 6 hours of reconstitution. Shelf life: 36 months (lyophilized).

Limited formal interaction studies. Can be co-administered with other inactivated vaccines at different sites (based on general principles). No known drug interactions. Concurrent immunosuppressive therapy may reduce immune response.

Pregnancy: contraindicated (insufficient data, and pre-vaccination screening not validated in pregnancy). Breastfeeding: no data; inactivated vaccine expected to be safe, but withhold if possible. Risk-benefit if occupational exposure is ongoing.

Not approved for children <15 years (Q-Vax). Limited safety and efficacy data in pediatric populations. Q fever is uncommon in children but does occur in rural/agricultural settings.

No specific dose adjustment. Elderly with occupational exposure history more likely to be seropositive — pre-screening especially important.

MANDATORY pre-vaccination screening: skin test (CST) + serology. Do NOT vaccinate without screening — risk of severe adverse reactions in pre-immune individuals. Screening protocol: blood draw for Q fever IgG/IgM serology AND intradermal CST (0.02 mL, read at 7 days). Only vaccinate if both negative. Post-vaccination: observe for 30 minutes. Injection site may remain tender for 1–2 weeks.