The Johnson & Johnson Janssen vaccine

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CDC scientists say their investigation into a rare blood clotting problem related to the Johnson & Johnson Covid-19 vaccine identified 28 people who may have developed life-threatening blockages – three of whom have died.

The Food and Drug Administration and Centers for Disease Control and Prevention urged states on April 13 to temporarily cease use of J & J’s vaccine “out of caution” while examining six women ages 18 to 48 who developed cerebral venous sinus thrombosis, or CVST combined with low platelets within about two weeks of receiving the shot.

They recommended resuming use of the shot 10 days later after the CDC found the benefits of the vaccinations outweighed their risks.

CVST is a form of thrombosis with thrombocytopenia, or TTS, which are blood clots with a low platelet count that make patients at risk of stroke. Platelets actually help the blood to clot.

CDC official Dr. Tom Shimabukuro said Wednesday that four of the 28 people with TTS were hospitalized on May 7, one of whom was in intensive care, and two were being discharged to a post-acute care facility. The remaining 19 patients have all been discharged, he said during a presentation to the CDC Advisory Committee on Immunization Practices. The panel voted earlier in the day to recommend the Pfizer BioNTech vaccine for 12 to 15 year olds.

The mean age of the patients with TTS was 40 years and ranged from 18 to 59 years. Women aged 30 to 39 were the greatest risk group. All patients received the J&J shot before the April 13 break. Of the 28 TTS cases, 19 involved the brain, with 10 of those patients suffering from cerebral haemorrhage, he said.

The other clots formed in the lower extremities, pulmonary arteries, or other areas of the body.