It’s a PReP, or prophylactic for immune compromised folks. It’s the first neutralizing antibody that I’ve heard about. (Regular vaccines allow a decent response once infected, but do not neutralize)

I couldn’t locate any papers (yet) or study descriptions. But from their website, I can share a quote from late 2023. Didn’t see the side effects yet. Etc. This says no SAEs.

“On December 18, 2023, Invivyd announced positive initial results from the ongoing CANOPY pivotal clinical trial. VYD222 produced high serum virus neutralizing antibody (sVNA) titer levels against XBB.1.5 in the immunocompromised cohort. The company observed an encouraging, potential early signal of strong clinical protection from symptomatic COVID-19 in CANOPY, which would be expected based on the high sVNA titer levels and dose selected. In addition, the company believes that the initial results from CANOPY support an immunobridging approach which utilizes in vitro VYD222 potency data to calculate and efficiently determine the sVNA titer levels against new SARS-CoV-2 variants as they emerge. Initial results showed that the safety and tolerability profile of VYD222 remained favorable with no study drug related serious adverse events reported; adverse events attributed to VYD222 were Grade 1 or 2 (mild or moderate) in severity.
In vitro pseudovirus testing shows that VYD222 has potency against various SARS-CoV-2 variants currently circulating, including JN.1, which is currently the fastest growing variant in the U.S., as well as HV.1, BA.2.86, XBB.1.5.10/EG.5, and HK.3.”