12-05-2025
UK Study Confirms Long-Term Safety of COVID-19 Vaccine
Headache and fatigue were the most commonly reported incident adverse events of the AZD1222 (ChAdOx1 nCoV-19) COVID-19 vaccine in real-world settings across the United Kingdom; anosmia (loss of smell) and ageusia (loss of taste) were the most frequently reported adverse events of special interest.
METHODOLOGY:
This active surveillance study assessed the safety and utilisation of the AZD1222 COVID-19 vaccine in real-world settings across the United Kingdom between March 1, 2021, and April 6, 2023.
Researchers recruited 17,945 participants (median age, 50 years; 60.4% women; 79.2% White) from vaccination sites, including primary care practices and hospitals.
They collected follow-up data at weeks 1, 4, and 14 and at months 6, 9, 12, and 18 after the initial vaccination through electronic data capture forms to identify recipient-reported adverse events and their incidence.
TAKEAWAY:
Overall, 19,824 adverse events were reported in 6591 participants, which included 399 serious adverse events in 220 participants and 287 adverse events of special interest in 184 participants.
Headaches had the highest incidence rate at 421.28 cases per 1000 person-years (95% CI, 404.88-438.34), followed by fatigue at 386 cases per 1000 person-years (95% CI, 370.46-402.18).
Anosmia and ageusia were the most frequently reported adverse events of special interest. An increased observed-to-expected ratio was noted for anosmia and/or ageusia (39.23; 95% CI, 29.13-49.32) and anaphylaxis (7.38; 95% CI, 2.80-11.95).
During the study period, 11 deaths were reported, with COVID-19 infection being the primary cause for two deaths and thrombosis for one death.
IN PRACTICE:
"This study highlights the requirement for pandemic preparedness, including the ongoing focus on standardising case definitions and producing background rates for AESIs [adverse events of special interest], thereby facilitating the rapid identification of safety signals via Observed versus Expected analysis," the authors wrote.
SOURCE:
This study was led by Alison Evans, Drug Safety Research Unit, Southampton, England. It was published online on May 02, 2025, in BMJ Open .
LIMITATIONS:
The study population showed demographic imbalances, with the underrepresentation of older adults and ethnic minorities. A significant loss to follow-up occurred at each timepoint, potentially leading to underreporting of longer-term outcomes.
DISCLOSURES:
This study was supported by AstraZeneca UK Limited. The authors reported having no competing interests.
