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Known adverse effects of messenger RNA covid-19 vaccines
as of mid-2021

FEATURED REVIEW With several hundred million people worldwide now vaccinated with an mRNA vaccine, surveillance conducted by various pharmacovigilance teams has identified a few signals of very rare adverse effects, notably pericarditis and myocarditis.
Full review (2 pages) available for download by subscribers.

Key points

  • The initial evaluation of the mRNA covid­19 vaccines tozinameran (Comirnaty°, marketed by Pfizer and BioNTech) and covid­19 vaccine mRNA­1273 (Spikevax°, marketed by Moderna) demonstrated an adverse effect profile consisting mainly of frequent local and systemic reactions within days of administration, hypersensitivity reactions, cardiac arrhythmias and hypertension.
  • A number of other adverse events have been reported in mRNA covid­19 vaccine recipients, as of early July 2021. They appear to occur very rarely:
    • pericarditis and myocarditis that usually occurred within 14 days of the second injection in adolescents or young men up to the age of 30 years, and regressed within a few days
    • facial oedema in vaccinees who had previously received injections of hyaluronic acid as a dermal filler for cosmetic purposes
    • sometimes-fatal acute pancreatitis
    • polyradiculoneuropathy, including Guillain-Barré syndrome
    • acquired haemophilia
    • reactivation of viral infections
    • thrombocytopenia
    • haemorrhagic diseases
    • chilblain-like skin lesions of the extremities
    • nephropathies
    • rheumatoid arthritis flares.
  • Continue monitoring. As with any new drug, the potential long-­term adverse effects remain unknown.

©Prescrire 1 November 2021

Source: "Known adverse effects of messenger RNA covid-19 vaccines as of mid-2021" Prescrire International 2021; 30 (231): 264-265. Subscribers only.

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