The National Medicines Safety Agency (ANSM) is preparing a pharmacovigilance report on the Janssen coronavirus vaccine. It evokes a “ significant number of Janssen vaccine failures “. What is vaccine failure? Is the effectiveness of the Janssen vaccine in question?
Failure of vaccination and occurrence of severe cases
In France, it is the regional pharmacovigilance center (CRPV) of Grenoble and that of Lyon which are responsible for monitoring and reporting the adverse effects following a vaccination with the Covid-19 Janssen vaccine. This serum, which is the last to have been integrated into the vaccination campaign, has many advantages, particularly in terms of logistics. This is because it is an adenovirus vaccine which is administered in a single dose and which can be stored in a conventional refrigerator. Yet the CRPVs recently reported “ a significant number of cases of Janssen vaccine failures […] with in particular serious forms (death, intensive care) as well as an overrepresentation of patients vaccinated by Janssen in intensive care in 2 CHUs. “
According to the ANSM, vaccine failure results in the onset, at least 21 days after the injection, of a Sars-Cov-2 infection associated with symptoms and confirmed by an antigen test. As of August 26, 32 cases of vaccine failures with the Janssen vaccine have been reported and analyzed, including 29 severe cases. As a reminder, more than a million people have received this serum. The median age of vaccinated and infected patients is 68 years. As of August 31, 2021, 4 people have died from ” an ineffectiveness of the Janssen® vaccine », Affirms the ANSM. Therefore, ” this potential signal relating to vaccine failures of the COVID-19 Janssen® vaccine has been relayed for further investigation. “
A significant drop in efficiency?
After analyzes of the results of clinical trials, the effectiveness of the Janssen vaccine was estimated at 66.9% to protect moderate to severe forms of Covid-19. In real life, the data is not available. However, some scientific studies show reduced efficacy on the Beta and Gamma variants, while others have led experts to recommend the administration of a second dose of the product. In France, the Haute Autorité de Santé recommends injecting only an RNA vaccine (Moderna or Pfizer) as a booster shot, within 4 weeks after the first injection with Janssen serum. Indeed, according to her, “ the available data do not confirm the long-term efficacy of the one-dose vaccination schedule of Janssen® vaccine against the Delta variant. “
