March 1, 2024

Federal health officials have now confirmed 28 cases, including six in men, of a rare bleeding disorder in adults who have received the Johnson & Johnson Covid-19 vaccine.

Dr. Tom Shimabukuro, deputy director of the vaccination safety bureau at the Centers for Disease Control and Prevention, presented the new cases on Wednesday at a CDC advisory board meeting

The number is an increase from the 15 confirmed cases that were all women reported at the meeting last month.

Although officials have now identified a handful of cases in men, women – particularly between the ages of 30 and 49 – appear to be at increased risk. “The trend is that women in all age groups have higher reporting rates than men,” said Dr. Shimabukuro at the meeting.

Patients with the rare but serious disorder develop blood clots, often in the brain, as well as low levels of platelets, components of the blood that promote clotting. The disorder is a “rare, clinically serious, and potentially life-threatening condition,” said Dr. Shimabukuro.

Last month, after reports first emerged that six women who had received the vaccine had developed the disorder, federal health officials recommended discontinuing use of the vaccine during the investigation. They lifted the suspension 10 days later and warned the vaccine label of possible risks that suggest that there is a “plausible” link between the vaccine and the disease.

22 of the confirmed cases so far involved women and six men. All were adults between the ages of 18 and 59 who received the vaccine before the national break. (Another case was also recorded in a 25-year-old male who participated in the clinical trial.)

Three people have died and four remain in the hospital, including one in intensive care. No new deaths have been documented since last month’s meeting, said Dr. Shimabukuro.

The overall risk remains extremely low. More than 9 million doses of the Johnson & Johnson vaccine have now been administered in the United States.

There were 12.4 cases per million doses in women between 30 and 39 years of age and 9.4 cases per million doses in women between 40 and 49 years of age, the two demographics that appear to be at greatest risk. There were fewer than 3 cases per million doses in older women and men of all ages.

Of the 28 confirmed cases, 12 people who developed the disorder had obesity, 7 had high blood pressure, 3 had diabetes, and 3 were taking estrogen, although it is not yet clear whether any of these factors could significantly increase the risk of the disorder.

Officials will continue to look for cases of the coagulation disorder in vaccinated people, said Dr. Shimabukuro.

There were no confirmed cases of coagulation disorder after the Pfizer BioNTech or Moderna vaccines, which use a different technology, said Dr. Shimabukuro.