Most patients immunosuppressed for a rheumatic disease are generating immune responses to SARS-CoV-2 vaccination, but questions remain over what constitutes an effective response and the need for boosters, according to an expert panel convened by the American College of Rheumatology (ACR).
Speaking at an ACR webinar, Dr Alfred Kim, Assistant Professor of Medicine at Washington University noted that studies currently showed that following vaccination between 75% to 94% of immunosuppressed patients will become seropositive – irrespective of what medication they are taking – compared to 95% to 100% of those immunocompetent.
However, while antibody titres generally showed lower levels of antibodies in those immunocompromised, it was yet unknown whether this correlated to a lower level of protection against the SARS-CoV-2 virus.
“There is a modest decrease in [antibody] levels compared to the immunocompetent group, anywhere between 1.4-fold to 3-fold less. Does this mean you’re less protected? This is an answer I can’t provide and I don’t think we’re going to have an answer for this anytime soon,” Dr Kim said.
“What is encouraging though, is that for most of these people, neutralisation titres seem to correlate well with antibody titres. I think this again highlights that vaccination of the immunosuppressed in those with rheumatic diseases is effective for the most part.”
“Certain medications will drive greater decreases than others,” he added, highlighting that current evidence showed B cell depleting therapies (BCDT) were linked with the greatest drops in seropositivity rates (26%-28%) and antibody titres (reductions between -7 and -625).
The recent COVaRiPAD study, which involved 133 adults with chronic inflammatory disease (CID) and 53 controls, found that BCDT and glucocorticoids substantially impaired immunogenicity of mRNA vaccines to SARS-CoV-2, with 36- and 10-fold reductions in antibody titres respectively.
With regard to BCDT, the latest evidence suggested the time between medication and vaccination seemed to be playing a key role in patient response.
In the COVaRiPAD study, “patients on rituximab begin to start generating [antibody] titres from about 6 months between the last dose of rituximab and the time they got vaccination,” Dr Kim noted.
This follows data showing that the presence of peripheral blood B cells “appear to be a key measure of whether or not you will generate antibody response to vaccine after BCDT,” he said.
Panel member Dr Jean Liew, Assistant Professor of Rheumatology at Boston University, presented (as yet unpublished) data from the GRA Vax Survey which showed that of the 2,860 patients who responded (67%) with stable rheumatic disease were willing to temporarily discontinue their medication when receiving their COVID-19 vaccination, if that would help its effectiveness.
Survey results also showed that 47.9% of patients reported having at least one adverse effect lasting for at least 2 days, though the most common – fatigue or sleepiness (33.4%), headache (27.7%) and muscle/joint pain (22.8%) – were all commonly associated with COVID-19 vaccination in the general population.
According to the data, while 13.4% reported experiencing a flare that lasted at least 2 days following vaccination, less than 5% reported have a flare that required a change in dosing of medication.
Overall, the key message for physicians is that “current data suggest that the vast majority of rheumatic patients safely receive COVID vaccination that produces immune response,” webinar attendee Dr Jeffrey Sparks, Assistant Professor of Medicine, Brigham and Women’s Hospital and Harvard Medical School, told the limbic.
However, he also emphasised that “more work needs to be done to understand the possible role of booster vaccine doses and to optimise vaccine response and mitigate COVID-19 risk for vulnerable patients, particularly those on B cell depleting therapies such as rituximab”.