How would you advise patients with known stable autoimmune thrombocytopenia regarding the Ad26.COV2.S (Johnson & Johnson/Janssen) vaccine?

For patients with autoimmune thrombocytopenia due to SLE, I favor avoiding vaccines that employ a viral vector due to concerns for viral induced lupus flare.

For patients with thrombocytopenia in association with antiphospholipid antibodies, would avoid the Johnson & Johnson (as well as Astra-Zeneca) Covid-19 vaccines due to the small but definite increased risk of induced thrombosis that may be antibody mediated.

Absent these two circumstances, the J&J vaccine may be OK to use. But given the known associations of adenoviral vectors with thrombocytopenia as well as uncertainty as to whether a patient with autoimmune mediated low platelets truly does not have evolving SLE or does not have a component of immune mediated thrombophilia, if the Moderna or Pfizer vaccine is an available option for these patients, would favor the use of these over the J&J and A-Z vaccines for Covid-19 immunization.