CDC and FDA have recommended that use of Johnson & Johnson’s Janssen (J&J/Janssen) COVID-19 Vaccine resume in the United States, effective April 23, 2021. However, women younger than 50 years old especially should be aware of the rare risk of blood clots with low platelets after vaccination, and that other COVID-19 vaccines are available where this risk has not been seen.
Thrombosis with Thrombocytopenia Syndrome (TTS)
CDC has identified 28 cases of thrombosis with thrombocytopenia syndrome (TTS) among more than 8.7 million people who have received the single shot Johnson & Johnson vaccine. So far, three persons have died and four remain hospitalized. The events appear similar to what is being observed with the AstraZeneca COVID-19 vaccine which is being used primarily in Europe. Both the Johnson & Johnson and AstraZeneca vaccines are adenovirus vector vaccines. This side effect has not been reported in persons taking the mRNA vaccines made by Pfizer and Moderna which have administered 135 and 110 million doses respectively.
Most of the cases were among women aged 18-49, with those aged 30-39 at highest risk, 12.4 cases per million or one in every 80,000. Those aged 40-49 had 9.4 cases per million or one in every 106,000. Six of the blood clots occurred in men. Risks for developing TTS include: women 18-50 years of age, men up to 60 years of age, obesity, hypertension, diabetes and taking birth control pills.
These vaccine-related events happened several days after receiving the vaccine up to two weeks later.
The Advisory Committee on Immunization Practices which advises CDC recommended on April 23, 2021 that the 10-day pause on administering the vaccine be lifted, although the decision was not unanimous. The Committee has reviewed the updated information but has not changed their recommendation at this time.
For now, anyone considering the Johnson & Johnson vaccine should be made aware of the risks and alternatives that are available.
CDC Guidance