CDC's ACIP Extends Pause on Janssen COVID-19 Vaccine Until More Data Becomes Available

April 15, 2021

By Denise Baez

The Centers for Disease Control and Prevention’s (CDC’s) Advisory Committee on Immunization Practices (ACIP) held an emergency meeting today, April 14, 2021, to consider the implications of new safety signals observed after administration of Janssen’s adenovirus vector coronavirus disease 2019 (COVID-19) vaccine (Ad26COV2.S).

All members of the ACIP expressed concerns regarding the clotting events that have been reported, and that are possibly associated with the vaccine; however, they were unable to vote whether the “pause” on the vaccine should be indefinite based on the currently available data.

The ACIP will reconvene in 1 week when more information becomes available. At that time, they hope to be able to make a more definitive recommendation.

The Janssen COVID-19 vaccine, which requires only 1 dose, received emergency use authorization (EAU) from the US Food and Drug Administration (FDA) in February 2021.

As of April 12, 2021, more than 6.8 million doses of the Janssen/J&J COVID-19 vaccine have been administered in the United States. As of April 10, 2021, there have been 6 cases of cerebral venous sinus thrombosis (CVST) with thrombocytopenia reported to the Vaccine Adverse Event Reporting System (VAERS). All 6 cases were females aged 18 to 48 years. None of the women were pregnant or in the postpartum period, and none had pre-existing conditions that would provoke thrombotic events.

There have been no cases of CVST with thrombocytopenia after administration of the Pfizer mRNA COVID-19 vaccine, and there have been 3 cases of thrombocytopenia after administration of the Moderna mRNA COVID-19 vaccine.

Cases of CVST with thrombocytopenia are rare but clinically serious. Observed cases appear to exceed expected cases based on background rates of CVST among women aged 20 to 50 years (≥3-fold).

The risk factors for CVST and thrombocytopenia is unknown. Headaches appear to be the main presenting feature, and physicians should maintain a high level of suspicion in patients presenting with headache after receipt of the Janssen COVID-19 vaccine. Median time to symptom onset is 8 days.

If possible, patients suspected of having CVST and thrombocytopenia should be screened with a PF4 ELISA assay for autoimmune heparin-induced thrombocytopenia (HIT).

Timely management of CVST with thrombocytopenia is crucial, and treatment options include intravenous immunoglobulin (IVIG) and anticoagulants. Consultation with a haematologist is strongly recommended.

Healthcare professionals should NOT administer heparin to patients presenting with thrombotic events and thrombocytopenia after receiving the Janssen vaccine.

Another adenovirus vector COVID-19 vaccine, made by AstraZeneca, which has been authorised for use in Europe (no doses have been administered) and the United Kingdom, is awaiting an EUA from the FDA. The AstraZeneca vaccine requires 2 doses.

In the United Kingdom, there have been 79 cases of thrombosis and thrombocytopenia following administration of the AstraZeneca vaccine, of which 19 were fatal. There were also 44 cases of CVST, of which 14 were fatal, and 35 cases of other types of clots, of which 5 were fatal.

Last week, the European Medicines Agency’s (EMA’s) Safety Committee released a report concluding that there was a strong association and a probable causal link between the AstraZeneca COVID-19 vaccine and rare clotting events. Most cases occurred in females aged younger than 60 years and within 2 weeks of vaccine administration.


SOURCE: Centers for Disease Control and Prevention