Toleration of mRNA Vaccines in Those with Antiphospholipid Antibodies

October 28, 2021

A research article published last week in The Lancet assessed the safety and tolerability of mRNA COVID-19 vaccines in people with antiphospholipid antibodies. In a survey of 102 vaccinated patients (67 who received Pfizer and 35 who received Moderna), 52 had an antiphospholipid syndrome diagnosis and 50 had antiphospholipid antibodies without clinical features of the syndrome. While 76% experienced at least one side effect, they were reported to be mild in 72 patients and moderate in 30. Side effects included pain at the injection site (44%), fatigue (36%), and headache (28%) and were reportedly transient and self-limiting within 10 days.

More specific vaccine responses included “one patient with thrombotic antiphospholipid syndrome and a known history of mild thrombocytopenia (110,000/mm³), who was on long-term vitamin K antagonist therapy, reported the occurrence of self-limiting purpuric lesions on her calves 10 days after the second dose. Blood tests were unremarkable except for a single transient fluctuation of platelet count (88,000/mm³). Consequent investigations (during an observation time of 5 months) showed a platelet count persistently above 100,000/mm³.”

Overall, there were no major adverse effects nor thrombotic events and side effects were mild and transient in nature. While more investigation is needed, the researchers concluded that the mRNA vaccines seem to have an “acceptable safety and tolerability profile in patients with antiphospholipid antibodies.”