CDC COVID-19A CDC advisory committee decided not to vote on how Johnson & Johnson’s COVID-19 vaccine should be deployed, reasoning that it needs more time to review data related to rare blood clots potentially linked to the vaccine. 

The Advisory Committee on Immunization Practices (ACIP) could ultimately help the CDC decide whether to continue using the vaccine, constrain it or discontinue it altogether. 

The cases of cerebral venous sinus thrombosis in J&J COVID-19 recipients deserve serious attention, said Dr. Sarah Long, an ACIP member in the meeting. “Even though it is a very small risk, it is very serious,” explained Long, who is also a professor of pediatrics at the Drexel University College of Medicine. The blood clotting disorder could pose “severe consequences,” Long said. 

Several members on the panel stressed they did not want to indefinitely pause the use of the J&J vaccine.

But continuing to roll out the vaccine without more data and deliberation would be “the wrong message and a real mistake to the people who would be getting this,” Long reasoned. “We are not able to inform them accurately at this moment about the benefit and risks.” 

ACIP plans to meet again in the coming weeks to deliberate on the topic. 

At the moment, however, the committee concluded it didn’t have enough data to make a firm determination. “I think we can’t parcel out groups that are more at risk or less at risk because we don’t have enough information,” Long said. 

To date, the CDC knows of six women between the ages of 18 and 48 who developed cerebral venous sinus thrombosis (CVST) after receiving the Johnson & Johnson vaccine. The agency anticipates collecting data on similar cases of the rare blood clotting problem occurring simultaneously with a low-platelet count. 

Roughly 1.5 million doses of the J&J vaccine were administered to women 18 to 50 years of age.

A number of recipients of the AstraZeneca COVID-19 vaccine have developed similar clinical symptoms. Some 62 people in the E.U. have developed CVST after receiving the vaccine. There were 44 such cases in the U.K. In the E.U., there were also 24 cases of splanchnic vein thrombosis with low platelet count. 

Regulatory authorities in Europe have included that the AstraZeneca vaccine’s benefits outweigh the risks, although Denmark has ceased using it. Other European countries have recommended that its use be constrained. 

A recent NEJM paper reflecting on the rare blood clots linked to the AstraZeneca vaccine referred to the condition as “vaccine-induced immune thrombotic thrombocytopenia.”