Key clinical point: Decreased SARS-CoV-2 antibody level is the major contributor to breakthrough SARS-CoV-2 infection in vaccinated patients with multiple sclerosis (MS) on various disease modifying therapies (DMT), with the third dose significantly reducing the risk for infection.
Major finding: After the second vaccine dose, the only significant factor associated with the risk for breakthrough infection was low antibody level (hazard ratio [HR] 0.51; P < .001), with the third dose reducing the risk for infection by 56% (HR 0.44; P = .025) during the Omicron wave.
Study details: Findings are from a prospective study of 1705 patients with MS on various DMT who received 2 doses of BNT162b2 (BioNTech-Pfizer) (n = 1391) or mRNA-1273 (Moderna) (n = 314) SARS-CoV-2 vaccine, with most receiving the third dose.
Disclosures: This study was funded by Fondazione Italiana Sclerosi Multipla. Some authors declared receiving grants, travel compensation, speaker honoraria, or advisory board/lecture and consulting fees from various sources.
Source: Sormani MP et al. Breakthrough SARS-CoV-2 infections after COVID-19 mRNA vaccination in MS patients on disease modifying therapies during the Delta and the Omicron waves in Italy. EBioMedicine. 2022;80:104042 (May 4). Doi: 10.1016/j.ebiom.2022.104042