April 13, 2021: Pause in Johnson & Johnson COVID-19 Vaccine

On April 13, 2021, the U.S. Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA) jointly recommended a temporary pause in the use of the Johnson & Johnson (J&J) COVID-19 vaccine. This decision was made after reports emerged of rare but severe cases of blood clots in individuals who had received the vaccine.

Context and Background

The Johnson & Johnson vaccine, also known as the Janssen COVID-19 vaccine, was granted Emergency Use Authorization (EUA) by the FDA on February 27, 2021. It was the third COVID-19 vaccine to be authorized in the United States, following the Pfizer-BioNTech and Moderna vaccines. Unlike the other two, the J&J vaccine required only a single dose, making it a crucial tool in the effort to vaccinate large populations quickly.

Key Events Leading to the Pause

• Reports of Blood Clots: By April 2021, approximately 6.8 million doses of the J&J vaccine had been administered in the U.S. The CDC and FDA received reports of six cases of a rare and severe type of blood clot known as cerebral venous sinus thrombosis (CVST) occurring in combination with low levels of blood platelets (thrombocytopenia). These cases were observed in women between the ages of 18 and 48, with symptoms appearing 6 to 13 days post-vaccination.

• Decision to Pause: The pause was recommended as a precautionary measure to allow health experts to investigate these cases further and to ensure that healthcare providers were aware of the potential for such adverse events and could recognize and manage them appropriately.

Broader Implications

• Public Health Response: The pause allowed the CDC’s Advisory Committee on Immunization Practices (ACIP) to review the data and assess the risks. This was part of a broader effort to maintain transparency and public trust in the vaccination process.

• Impact on Vaccination Efforts: While the pause temporarily slowed the rollout of the J&J vaccine, it underscored the importance of vaccine safety monitoring systems. The Pfizer-BioNTech and Moderna vaccines continued to be administered during this period.

Aftermath

• Resumption of Use: On April 23, 2021, after a thorough safety review, the CDC and FDA lifted the pause on the J&J vaccine, with updated guidance on the risks and benefits. They concluded that the benefits of the vaccine outweighed the risks, but added a warning about the rare clotting disorder.

• Continued Monitoring: The event highlighted the importance of ongoing monitoring for vaccine safety and the ability of health agencies to respond swiftly to potential issues.

The pause and subsequent resumption of the J&J vaccine demonstrated the robustness of the U.S. vaccine safety monitoring system and the commitment to ensuring public health and safety during the COVID-19 pandemic.