COVID-19 Vaccine AstraZeneca
Administration
Vaccine
- COVID-19 Vaccine AstraZeneca
Authorized for Use in
- Health Canada, EU EMA, UK, WHO EUL, Australia TGA
- U.S. FDA EUA application date now uncertain.
Age
- ≥ 18 yrs. Trial for age 12-17 yrs currently paused. Many countries not using in adults under 60 due to thrombosis AE.
Type
- Nonreplicating chimpanzee adenovirus vector
Primary Dosing
- 0.5 mL IM; 2 doses 4-12 wks apart (UK & EU), 4 wks in US trial, 8-12 weeks under WHO EUL
Booster Dosing
- No application in process. Booster recommendations are generally to use an mRNA vaccine
Interchangeability
-
CDC recommends that persons aged ≥ 18 years (including moderately or severely immunocompromised persons who received an additional primary dose) who were fully vaccinated with a WHO EUL vaccine not authorized/approved by US FDA or with a heterologous series composed of any FDA-authorized/approved or WHO EUL authorized vaccine are eligible to receive a single booster dose of the Pfizer vaccine (0.3 mL; 30 µg) at least 6 months after completion of their primary series under the existing age guidelines as for Moderna and Pfizer vaccines. Practically, either mRNA vaccine may be used for a booster in this situation.
Storage
- 2-8°C for 4-5 months. After puncture store at 2-25oC for 6 hours
Efficacy
Overall against symptomatic disease
- 76% (US trial; n=33,000). 62% based on UK approval using other heterogeneous results from multiple combined trials. 82.4% if dose 2 given >12 weeks after dose 1.
- Overall Efficacy against symptomatic disease in Phase 3 trials pre-delta. Specific VE data against beta, gamma no longer relevant.
Real world against hospitalization
- 60% VE against symptomatic disease from delta, compared to 66% VE against alpha.
Age > 65 years
- 80%
Pediatric
- Not approved
Against severe disease / death
- Approx 100% in Phase 3 trials (pre-delta)
Against asymptomatic infection / transmission
- 65% (pre-Delta)
Duration of efficacy after final dose
- Duration against delta variant especially in immunocompromised and elderly is unknown and of concern.
Toxicities
Contraindications
- Anaphylactic reaction to a vaccine constituent
Precautions
- Women aged <50 years should be educated about the rare risk of thrombosis with thrombocytopenia syndrome (TTS) with the Astra Zeneca vaccine as well as the availability of alternative COVID-19 vaccines to guide joint vaccine decisionmaking with the provider.
- Postpone vaccination in persons with acute severe febrile illness. Rx with IVIG, N Engl J Med 385:720-8, 2021
Not contraindications
- No data
Adverse effects
- Injection-site pain, fatigue, headache, fever, and weakness.
- TTS in 1:25,000 to 1: 100,000 vaccinees in Europe.
- No data yet on overall rate of PF4 antibodies or thrombocytopenia. N Engl J Med 2021, 384:2124
Special Needs Populations
Pregnancy
- Unknown
Immunocompromised / HIV
- Insufficient data