An official health alert was issued by the CDC the same day, based on reports from the Vaccine Adverse Event Reporting System that associated the vaccine with six cases of cerebral venous sinus thrombosis seen in combination with thrombocytopenia. All six cases occurred among white women between the ages of 18 and 48. Symptoms occurred between six and 13 days after vaccination. Four patients developed focal neurological symptoms and one patient died from intraparenchymal brain hemorrhage. These cases were similar to those observed in some patients who received the AstraZeneca vaccine, which has not been approved for use in the United States.
Based on the VAERS data, the CDC and FDA issued a recommendation to pause the use of the vaccine to allow for review of the cases and additional data by the CDC’s Advisory Committee on Immunizations Practices.
The ACIP held an emergency meeting on April 14 and discussed the six identified cases as well as data related to vaccine distribution and background incidence of CVST. The committee has requested additional information and will reconvene for another emergency meeting in the near future.
According to the CDC, nearly 7 million doses of the Janssen/Johnson & Johnson vaccine have been administered in the United States. Patients who have already received the vaccine are advised to seek urgent medical care if they develop any of the following symptoms:
As of April 13, no cases of CVST with thrombocytopenia have been reported in individuals who have received the Pfizer-BioNTech or Moderna COVID-19 vaccines.
The decision to pause administration of the Janssen/Johnson & Johnson vaccine is important to family physicians for a number of reasons.
First, the pause is being done out of an abundance of caution and is evidence that the VAERS monitoring system works and has been able to rapidly identify these cases. Patients who have received the Janssen/Johnson & Johnson vaccine should be counseled that this is a rare event but should be aware of the potential symptoms and when to seek urgent care.
Second, clinicians are being asked to maintain a high level of suspicion when evaluating patients presenting with the symptoms above who have also received the vaccine.
Third, if a blood clot is identified in a patient who received the vaccine, the CDC recommended that screening be conducted to detect the presence of anti-PF4 antibodies, which is indicative of heparin-induced thrombocytopenia. The use of heparin in patients with thrombotic events with thrombocytopenia following receipt of the Janssen/Johnson & Johnson vaccine is not recommended unless HIT testing is negative. If HIT is present or if testing is not available, alternative treatments should be considered, such as non-heparin anticoagulants and high-dose intravenous immune globulin.
Fourth, the pause is not anticipated to be extensive, as the ACIP is aware that prolonged disruptions may impact equity in vaccine administration. The committee is expected reconvene as soon as information becomes available over the next one to two weeks.
“We are watching science in action and seeing first-hand the importance of a robust safety monitoring process,” said Julie Wood, M.D., M.P.H, the Academy’s senior vice president for research, science and health of the public. “Vaccines are safe and effective, and family physicians are ideally positioned to continue to educate, promote and administer COVID-19 vaccines in order to mitigate and ultimately end the COVID-19 pandemic.”