CDC sees more blood clot cases linked to the Johnson & Johnson vaccine
Four patients remained hospitalized as of Wednesday, with one in intensive care, and three patients have died.
Photo: zoranm/Getty Images
The U.S. Centers for Disease Control and Prevention has identified 11 more cases of serious blood clots among Americans who have received the Johnson & Johnson COVID-19 vaccine, according to a CDC official. This brings the total number of cases to 28 out of about 8.7 million, an uptick from the 17 cases that were recorded as of April 25.
While the numbers suggest that these blood clots are extraordinarily rare, Dr. Tom Shimabukuro, who leads the CDC's COVID-19 vaccine safety monitoring network, told NBC News on Wednesday that there's a plausible "causal association" between the Johnson & Johnson vaccine and thrombosis with thrombocytopenia syndrome, a condition in which blood clots are present in combination with low platelet levels.
Thrombosis events were the primary catalyst behind the federal government's pause of the Johnson & Johnson vaccine in April, when six women reportedly developed blood clots after being vaccinated. One case was fatal, that of a 45-year old woman with no risk factors who received the vaccine and developed cerebral venous sinus thrombosis with hemorrhage. All of the other five blood clotting events were also reported in females, ages 26 to 59.
In total, nineteen patients have developed cerebral venous sinus thrombosis. While most blood clotting events occurred in women between the ages of 19 to 49, six occurred in men, with symptoms occurring three to 15 days after vaccination, according to the NBC report.
Four patients remained hospitalized as of Wednesday, with one in intensive care, and three patients have died. Two were sent to post-acute care facilities, while 19 have been discharged home.
The government lifted its pause of the Johnson & Johnson vaccine on April 23.
WHAT'S THE IMPACT?
To date, no blood-clotting issues have been linked to the Pfizer-BioNTech or Moderna vaccines, despite 135 million doses of the former and 110 million doses of the latter. But the concerns are similar to those raised about the AstraZeneca vaccine, which is in use abroad, but not in the U.S.
In April, the European Medicines Agency found a possible link between the AstraZeneca vaccine and blood clots in combination with low platelets.
The CDC finding that the Johnson & Johnson vaccine may have a causal link to blood clotting somewhat contradicts research published last month in the New England Journal of Medicine, which found scant evidence of such an association. The scientists conducting the research, who work for Johnson & Johnson, said that out of 75,000 participants in a clinical trial, there was just one case of cerebral venous sinus thrombosis.
J&J scientists said in their letter that the blood clot cases "are occurring within the range of published background incidence," meaning they're occurring roughly at the normal rate of incidence among the general population.
"We continue to work closely with experts and regulators to assess the data, and we support the open communication of this information to healthcare professionals and the public," the scientists wrote.
THE LARGER TREND
The trouble with the J&J vaccine began in early April, when vaccination sites in North Carolina and Colorado shut down temporarily after an abnormal number of adverse reactions to the vaccine.
Eleven people at a vaccine site at Dick's Sporting Goods in Commerce City, Colorado, experienced adverse side effects ranging from dizziness to nausea. The North Carolina site closed after patients there reported similar reactions.
At that time there was no reason to believe that there was anything wrong with the vaccine itself. Colorado public health officials said they found no sign of a problem with the single-dose offering.
Then the blood-clot cases occurred. While they're still considered extremely rare, the vaccine was put on hold, and federal officials stressed that there was more than enough supply of the Moderna and Pfizer vaccines to go around.
In addition to blood clotting cases, concern arose recently over anxiety-induced reactions to the Johnson & Johnson vaccine. The initial closure of vaccination sites in five states were linked to these events, but those symptoms were likely due to preexisting anxiety issues in patients rather than the vaccine itself, the CDC said in a May report.
Overall, 64 anxiety-related events among 8,624 recipients, including 17 incidences of fainting, were reported from those sites for vaccines administered from April 7-9. The CDC's finding was that anxiety-related events, including fainting, can occur immediately after a vaccination using any vaccine, and might be caused by anxiety about receiving an injection.
Twitter: @JELagasse
Email the writer: jeff.lagasse@himssmedia.com
