ABSTRACT
Introduction: Since the beginning of vaccination against COVID-19 in 2020, the occurrence of adverse events of special interest (AESI) after the 1st dose of vaccine raises the question of the potential risk associated with the following injections. Real-life vaccine data collected in pharmacovigilance databases can provide information about the safety of a rechallenge with COVID-19 vaccines. In order to help physicians to decide whether another injection is at risk, we analyzed the cases reported in the WHO pharmacovigilance database, Vigibase®. Material and methods: We identified AESI with major concerns about the safety of a rechallenge with COVID-19 vaccines: facial paralysis, immune thrombocytopenia, herpes viral infections, hypertension, hearing loss, Guillain-Barré syndrome (GBS), convulsions, myelitis, encephalitis, myocarditis, pericarditis and acute pancreatitis. We extracted cases with rechallenge of these AESI from VigiBase®, whether the AESI recurred or not, until 24 November 2021. The rate of recurrence of the initial AESI according to the vaccine platform was calculated. Results: 676 cases of AESI with COVID-19 vaccines reported information of recurrence after rechallenge, 320 with positive recurrence and 356 with no recurrence. Facial paralysis, herpes viral infection, GBS and myocarditis mostly did not reccur whatever the vaccine type. Whereas hypertension, hearing loss, convulsion and pericarditis seemed to reoccur only after rechallenge of mRNA vaccines, compared to others vaccines. There were few data for immune thrombocytopenia, encephalitis, myelitis and acute pancreatitis. Discussion/Conclusion: This study provided information about the safety of rechallenge of COVID-19 vaccines after first occurrence of AESI. Such information is of great importance considering that several booster shots are being proposed to populations to improve protection against COVID-19 variants. In case of AESI after COVID-19 vaccine, the decision to maintain the following dose must take into account the patient's individual risk benefit balance as well as his history. Although limited, our results provide clinical elements that may help decision-making.
ABSTRACT
Chloroquine and hydroxychloroquine are drugs that have shown in vitro activity on the replication of certain coronaviruses. In the context of the SARS-Cov-2 epidemic, the virus responsible for the novel coronavirus disease (COVID-19), these two drugs have been proposed as possible treatments. The results of the first clinical studies evaluating the effect of hydroxychloroquine do not support any efficacy of this drug in patients with COVID-19, due to major methodological weaknesses. Yet, these preliminary studies have aroused considerable media interest, raising fears of massive and uncontrolled use. In the absence of evidence of clinical benefits, the main risk is of exposing patients unnecessarily to the well-known adverse effects of hydroxychloroquine, with a possibly increased risk in the specific setting of COVID-19. In addition, widespread use outside of any recommendation risks compromising the completion of good quality clinical trials. The chloroquine hype, fueled by low-quality studies and media announcements, has yielded to the implementation of more than 150 studies worldwide. This represents a waste of resources and a loss of opportunity for other drugs to be properly evaluated. In the context of emergency, rigorous trials are more than ever needed in order to have, as soon as possible, reliable data on drugs that are possibly effective against the disease. Meanwhile, serious adverse drug reactions have been reported in patients with COVID-19 receiving hydroxychloroquine, justifying to limit its prescription, and to perform suitable cardiac and therapeutic drug monitoring.