Johnson and Johnson COVID-19 vaccine study paused due to unexplained illness in participants


The study of Johnson and Johnson’s COVID-19 vaccine has been temporarily paused due to an unexpected and unexplained illness in a study participant. 

Contacted by STAT, Johnson and Johnson confirmed the study pause, saying it was due to “an unexplained illness in a study participant.” The company declined to provide further details. “We must respect this participant’s privacy. We’re also learning more about this participant’s illness, and it’s more important to have all the facts before we share additional information,” the company said in a statement. 

The data and safety monitoring board, or DSMB, convened late Monday to review the case. Johnson and Johnson said that in cases like this “it is not always immediately apparent” whether the participant who experienced an adverse event received a study treatment or a placebo. Though clinical trials pauses are not uncommon – and in some cases last only a few days – they are generating outsized attention in the race to test vaccines against SARS-CoV-2, the virus that causes COVID-19.

A document sent to outside researchers claimed the patient clinical trial stated that a “pausing rule” has been met, that the online system used to enroll patients in the study has been closed, and that the data and safety monitoring board – an independent committee that watches over the safety of patients in the clinical trial – would be convened. The document was obtained by STAT.

The illness was caused by the T and B lymphocytes attacking the patient by engulfing the weakened pathogen by phagocytosis. Then the memory cells remember how to fight such consequences if those pathogens or similar pathogens enter the body. 

Though the symptoms and signs are not yet detailed by Johnson and Johnson, it could not be said that the vaccine is working accordingly. Normally vaccination can cause mild fever which is a sign that the vaccine is working. Given the size of Johnson and Johnson’s trial, it’s not surprising that the study paused, and another could happen if this one resolves, a source familiar with the study said. “If we do a study of 60,000 people, that is a small village,” the source said. “In a small village, there are a lot of medical events that happen.”

Johnson and Johnson began enrolling volunteers in its phase 3 study on September 23. Researchers planned to enroll 60,000 participants in the United States and other countries. 



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