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Federal health officials have lifted the pause on the Johnson & Johnson/Janssen (J&J/Janssen) one-shot COVID-19 vaccine, but women younger than age 50 should be aware that they are at risk of the rare but real side effect of blood clots. Overall, 15 women have had the reaction and three have died.
The reaction has not been observed in the other two vaccines approved for use in the United States, and the Pfizer and Moderna vaccines have continued to be administered.
The decision to recommend the J&J/Janssen vaccine again came after a meeting of the Centers for Disease Control and Prevention’s (CDC) Advisory Committee on Immunization Practices on April 23, 2021. Previously, at a press conference on April 13, 2021, the CDC and the U.S. Food and Drug Administration (FDA) announced the pause because there had been six blood clot cases in the United States after more than 6.8 million doses of the J&J/Janssen COVID vaccine were administered.
As of the April 23 meeting, more than 8 million doses of the J&J/Janssen COVID-19 vaccine had been given in the United States. An extensive review after the pause raised the total to 15 cases, including three women who died and seven who remain hospitalized. Of the latter, four patients are in intensive care. Five women survived the reaction and were discharged home.
“The reports reviewed all occurred in women between 18 and 59 years old, with a median of 37 years,” the CDC states. “These reports represent a reporting rate of seven such events per 1 million vaccinations among women 18 through 49 years old, and a rate of 0.9 per 1 million vaccinations among women 50 years and older. For all women, this is a rare adverse event. For women 50 years and older and men of all ages, the adverse event is even more rare. Reports show that symptoms of this adverse event started between 6 and 15 days after vaccination.”
A review of all available data at this time shows that the J&J/Janssen COVID-19 vaccine’s benefits outweigh its risks, the CDC concluded.
“However, women younger than 50 years old should be aware of the rare but increased risk of this adverse event and that there are other COVID-19 vaccine options available for which this risk has not been seen,” the CDC warned.
For three weeks after receiving the vaccine, be on the lookout for possible symptoms of this reaction, the CDC advises. Seek medical care immediately if you develop one or more of these symptoms:
Avoid Heparin Treatment for Cases
A key reason for the vaccination pause was to alert providers that normal anticoagulation treatment for blood clots like heparin may make this rare reaction worse.
“The issue here with these type of blood clots is that if one administers the standard treatments, one can actually cause tremendous harm or the outcome can be fatal,” Peter Marks, MD, PhD, director of the Center for Biologics Evaluation and Research at the FDA, said at the press conference. “We want to make sure if providers see people with low blood platelets or if they see people who have blood clots, they need to inquire about the history of recent vaccination.”
In the cases, cerebral venous sinus thrombosis (CVST) was seen in combination with thrombocytopenia — low levels of blood platelets. It is the combination of CVST clots and low platelet counts that is unusual, he said.
“The combination here — the real thing that is so notable — is not cerebral venous sinus thrombosis or thrombocytopenia,” he said. “Those two things can occur. It is the occurrence together that makes a pattern, and that pattern is very similar to what was seen in Europe with [AstraZeneca vaccine].”
Both the J&J/Janssen and AstraZeneca vaccines use benign adenoviruses to spur an immune reaction to SARS-CoV-2 spike proteins and prevent infection.
The CDC previously issued an alert on the issue that included the following recommendations for clinicians: