Incidence and outcome of COVID-19 following vaccine and hybrid immunity in patients on immunosuppressive therapy: identification of protective post-immunisation anti-RBD antibody levels in a prospective cohort study

OBJECTIVES

To assess incidence, severity and predictors of COVID-19, including protective post-vaccination levels of antibodies to the receptor-binding domain of SARS-CoV-2 spike protein (anti-RBD), informing further vaccine strategies for patients with immune-mediated inflammatory diseases (IMIDs) on immunosuppressive medication.

METHODS

IMIDs on immunosuppressives and healthy controls (HC) receiving SARS-CoV-2 vaccines were included in this prospective observational study. COVID-19 and outcome were registered and anti-RBD antibodies measured 2-5 weeks post-immunisation.

RESULTS

Between 15 February 2021 and 15 February 2023, 1729 IMIDs and 350 HC provided blood samples and self-reported COVID-19. The incidence of COVID-19 was 66% in patients and 67% in HC, with re-infection occurring in 12% of patients. Severe COVID-19 was recorded in 22 (2%) patients and no HC. No COVID-19-related deaths occurred. Vaccine-induced immunity gave higher risk of COVID-19 (HR 5.89 (95% CI 4.45 to 7.80)) than hybrid immunity. Post-immunisation anti-RBD levels <6000 binding antibody units/mL were associated with an increased risk of COVID-19 following three (HR 1.37 (95% CI 1.08 to 1.74)) and four doses (HR 1.28 (95% CI 1.02 to 1.62)), and of COVID-19 re-infection (HR 4.47 (95% CI 1.87 to 10.67)).

CONCLUSION

Vaccinated patients with IMID have a low risk of severe COVID-19. Hybrid immunity lowers the risk of infection. High post-immunisation anti-RBD levels protect against COVID-19. These results suggest that knowledge on COVID-19 history, and assessment of antibody levels post-immunisation can help individualise vaccination programme series in high-risk individuals.

TRIAL REGISTRATION NUMBER

NCT04798625.

Dynamics of SARS-CoV-2 immunity after vaccination and breakthrough infection in rituximab-treated rheumatoid arthritis patients: a prospective cohort study

Background

SARS-CoV-2 vaccination in rheumatoid arthritis (RA) patients treated with B cell-depleting drugs induced limited seroconversion but robust cellular response. We aimed to document specific T and B cell immunity in response to vaccine booster doses and breakthrough infection (BTI).

Methods

We included 76 RA patients treated with rituximab who received up to four SARS-CoV-2 vaccine doses or three doses plus BTI, in addition to vaccinated healthy donors (HD) and control patients treated with tumor necrosis factor inhibitor (TNFi). We quantified anti-SARS-CoV-2 receptor-binding domain (RBD) Spike IgG, anti-nucleocapsid (NC) IgG, 92 circulating inflammatory proteins, Spike-binding B cells, and Spike-specific T cells along with comprehensive high-dimensional phenotyping and functional assays.

Findings

The time since the last rituximab infusion, persistent inflammation, and age were associated with the anti-SARS-CoV-2 RBD IgG seroconversion. The vaccine-elicited serological response was accompanied by an incomplete induction of peripheral Spike-specific memory B cells but occurred independently of T cell responses. Vaccine- and BTI-elicited cellular immunity was similar between RA and HD ex vivo in terms of frequency or phenotype of Spike-specific cytotoxic T cells and in vitro in terms of the functionality and differentiation profile of Spike-specific T cells.

Interpretation

SARS-CoV-2 vaccination in RA can induce persistent effector T-cell responses that are reactivated by BTI. Paused rituximab medication allowed serological responses after a booster dose (D4), especially in RA with lower inflammation, enabling efficient humoral and cellular immunity after BTI, and contributed overall to the development of potential durable immunity.

Adalimumab serum levels and anti-drug antibodies: associations to treatment response and drug survival in inflammatory joint diseases

OBJECTIVES

To explore associations between serum adalimumab level, treatment response and drug survival in order to identify therapeutic drug levels for therapeutic drug monitoring of adalimumab. Also, to assess occurrence and risk factors of anti-drug antibody (ADAb) formation.

METHODS

Non-trough adalimumab and ADAb levels were measured by automated fluorescence assays in serum collected after 3 months of adalimumab treatment in patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA) or axial spondyloarthritis (axSpA) included in the observational NOR-DMARD study. Treatment response was evaluated after 3 months, and drug survival during long-term follow-up.

RESULTS

In 340 patients (97 RA, 69 PsA, 174 axSpA), median adalimumab level was 7.3 mg/l (IQR 4.0-10.3). 33 (10%) patients developed ADAb. Findings were comparable across diagnoses. In RA and PsA, adalimumab levels ≥6.0 mg/l were associated with treatment response (Odds Ratio [OR] 2.2 [95% CI 1.0, 4.4]) and improved drug survival (Hazard Ratio [HR] 0.49 [0.27, 0.80]). In axSpA, a therapeutic level could not be identified, but higher adalimumab levels were associated with response. Factors associated with ADAb formation were previous bDMARD use, no methotrexate comedication and use of adalimumab originator compared with GP2017.

CONCLUSION

Higher adalimumab levels were associated with better response and improved drug survival for all diagnoses, with a suggested lower threshold of 6.0 mg/l for RA/PsA. This finding, the large variability in drug levels among patients receiving standard adalimumab dose, and the high proportion of patients developing ADAb, encourages further investigations into the potential role of therapeutic drug monitoring of adalimumab.

Humoral immune response to SARS-CoV-2 vaccination in patients with inflammatory bowel disease on immunosuppressive medication: association to serum drug levels and disease type

OBJECTIVES

Immune responses following SARS-CoV-2 vaccination in patients with inflammatory bowel disease (IBD) are not well characterized. The aims of this study were to explore the serological response associated with IBD, and immunosuppressive medications including serum concentrations of biologics and thiopurine metabolites.

MATERIALS AND METHODS

This prospective, observational study included adult patients with ulcerative colitis (UC) and Crohn's disease (CD), and healthy controls. Antibodies to the receptor-binding domain of SARS-CoV-2 spike proteins, and serum concentrations of ongoing biologic and immunomodulatory medications were assessed prior to, and 2-5 weeks after the second vaccine dose. Serologic response was defined as anti-Spike antibodies ≥70 AU/ml.

RESULTS

In 958 IBD patients (380 UC, 578 CD) and 323 healthy controls, the median (Q1; Q3) anti-Spike antibody level (AU/ml) was lower in patients (618 (192; 4370)) compared to controls (3355 (896; 7849)) (p < 0.001). The antibody levels were lower in CD (439 (174; 3304)) compared to UC (1088 (251; 5975)) (p < 0.001). No associations were demonstrated between antibody levels and serum drug concentrations for TNF inhibitor (TNFi), vedolizumab and ustekinumab. Patients receiving TNFi + thiopurines with a subtherapeutic 6-thioguanine nucleotide (6-TGN) level had higher response rate (93%) compared to patients with 6-TGN within the therapeutic range (53%) (p = 0.003). A diagnosis of UC, mRNA-1273 vaccine, and other treatments than TNFi + thiopurines were associated with humoral response.

CONCLUSIONS

Patients with CD had an attenuated humoral response to SARS-COV-2 vaccination as compared to patients with UC. The lack of association between serum levels of biologics and serologic response indicates vaccination regardless of proximity to drug administration.

Four SARS-CoV-2 vaccine doses or hybrid immunity in patients on immunosuppressive therapies: a Norwegian cohort study

Background

Data on response and safety of repeated vaccinations and hybrid immunity in patients with immune-mediated inflammatory diseases on immunosuppressive therapy is needed to further develop vaccination strategies in this vulnerable population. This study aimed to evaluate hybrid immunity and humoral immune response and safety of four SARS-CoV-2 vaccine doses in patients with immune-mediated inflammatory diseases on immunosuppressive therapy.

Methods

This prospective observational Norwegian study of vaccine response to COVID-19 (Nor-vaC) included adult patients aged 18 years and older with immune-mediated inflammatory diseases (rheumatoid arthritis, spondyloarthritis, psoriatic arthritis, Crohn's disease, or ulcerative colitis) on immunosuppressive therapy, who had received four SARS-CoV-2 vaccine doses (vaccine group) or three vaccine doses followed by COVID-19 (hybrid group), and healthy controls receiving three vaccine doses (control group). Patients were recruited from the Division of Rheumatology at Diakonhjemmet Hospital, Oslo, and the Department of Gastroenterology at Akershus University Hospital, Lørenskog. Patients who had COVID-19 before the third vaccine dose, and patients with allergies or intolerances to elements of the vaccine were excluded. Antibodies to the receptor-binding domain of SARS-CoV-2 spike protein (anti-RBD antibodies) were assessed 2-4 weeks following vaccination or COVID-19. This study is registered at Clinialtrials.gov, NCT04798625.

Findings

Between Nov 12, 2021, and April 19, 2022, 1458 participants with immune-mediated inflammatory diseases provided post-vaccination samples at 2-4 weeks following a third vaccine dose. After 544 participants were excluded, 715 (78%) of the remaining 914 participants received the fourth dose of the vaccine, and of these, 536 (75%) provided post-vaccination samples 2-4 weeks after their fourth vaccination (vaccine group). 199 (22%) of the 914 had COVID-19 after their third dose of the vaccine and of these, 167 (84%) provided samples (hybrid group). 256 of the eligible 703 patients had rheumatoid arthritis, 107 had spondyloarthritis, 115 had psoriatic arthritis, 130 had Crohn's disease, and 95 had ulcerative colitis). Median age was 56 years [IQR 45-65], 398 (57%) were women, and 305 (43%) were men. Patients in the vaccine group had higher anti-RBD antibody concentrations following the fourth vaccine dose (median 6192 BAU/ml [IQR 2878-11 243]) than after the third dose (median 5087 BAU/ml [1250-9081]; p< 0·0001), but lower antibody concentrations than the control group following the third dose (median 7595 BAU/ml [5916-12 001]; p< 0·0001). Antibody concentrations were higher in the patients in the hybrid group (23 548 BAU/ml [IQR 11 440-35 935]) than in the vaccine group (p<0·0001). No difference was found in antibody concentrations between the fourth dose of BNT162b2 (full-dose) and mRNA-1273 (half-dose). Patients and controls had a comparable safety profile after both three and four vaccine doses.

Interpretation

Vaccine boosters improve humoral immune responses and are safe in patients with immune-mediated inflammatory diseases on immunosuppressive therapy, and administration should be considered regularly in this patient group. Hybrid immunity with omicron induces a strong humoral response suggesting longer intervals between booster doses in this patient group.

Funding

The South-Eastern Norway Regional Health Authority, The Coalition for Epidemic Preparedness Innovations, Akershus University Hospital.

Immunogenicity and safety of a three-dose SARS-CoV-2 vaccination strategy in patients with immune-mediated inflammatory diseases on immunosuppressive therapy

Objectives

Humoral vaccine responses to SARS-CoV-2 vaccines are impaired and short lasting in patients with immune-mediated inflammatory diseases (IMID) following two vaccine doses. To protect these vulnerable patients against severe COVID-19 disease, a three-dose primary vaccination strategy has been implemented in many countries. The aim of this study was to evaluate humoral response and safety of primary vaccination with three doses in patients with IMID.

Methods

Patients with IMID on immunosuppressive therapy and healthy controls receiving three-dose and two-dose primary SARS-CoV-2 vaccination, respectively, were included in this prospective observational cohort study. Anti-Spike antibodies were assessed 2–4 weeks, and 12 weeks following each dose. The main outcome was anti-Spike antibody levels 2–4 weeks following three doses in patients with IMID and two doses in controls. Additional outcomes were the antibody decline rate and adverse events.

Results

1100 patients and 303 controls were included. Following three-dose vaccination, patients achieved median (IQR) antibody levels of 5720 BAU/mL (2138–8732) compared with 4495 (1591–6639) in controls receiving two doses, p=0.27. Anti-Spike antibody levels increased with median 1932 BAU/mL (IQR 150–4978) after the third dose. The interval between the vaccine doses and vaccination with mRNA-1273 or a combination of vaccines were associated with antibody levels following the third dose. Antibody levels had a slower decline-rate following the third than the second vaccine dose, p<0.001. Adverse events were reported by 464 (47%) patients and by 196 (78%) controls. Disease flares were reported by 70 (7%) patients.

Conclusions

This study shows that additional vaccine doses to patients with IMID contribute to strong and sustained immune-responses comparable to healthy persons vaccinated twice, and supports repeated vaccination of patients with IMID.

Trial registration number

NCT04798625.

OP0192 SEROLOGICAL RESPONSE AND SAFETY OF A THREE-DOSE SARS-CoV-2 VACCINATION STRATEGY IN PATIENTS WITH IMMUNE-MEDIATED INFLAMMATORY DISEASES ON IMMUNOSUPPRESSIVE THERAPY

Background

Patients with immune-mediated inflammatory diseases (IMIDs) on immunosuppressive therapy have an inadequate serologic response following two-dose SARS-CoV-2 vaccination, and a standard vaccination strategy of three doses for this patient group is currently under implementation in several countries. However, the serological response and safety of this strategy has not been evaluated.

Objectives

To assess serological response and safety of a three-dose vaccination strategy in IMID patients on immunosuppressive therapy as compared to standard two-dose vaccination of healthy controls.

Methods

The prospective observational Nor-vaC study (NCT04798625) enrolled adult patients on immunosuppressive therapy for inflammatory joint- and bowel diseases. Healthy controls were health care workers from participating hospitals. All participants received standard vaccines according to the national vaccination program with three doses in patients and two doses in controls. The third dose was offered to IMID patients >4 weeks after the second dose. Analyses of antibodies binding the receptor-binding domain of the SARS-CoV-2 Spike protein were performed prior to, and 2-4 weeks after the second and third vaccine doses. Levels were compared across groups by Mann-Whitney U tests and multivariate linear regression was used to identify predictors of response.

Results

Overall, 961 patients (315 rheumatoid arthritis, 156 spondyloarthritis, 171 psoriatic arthritis, 132 ulcerative colitis and182 Crohn’s disease) (median age 54 years [IQR 43-64]; 56 % women) and 227 controls (median age 44 years [IQR 32-55]; 83 % women) were included in the present analyses. TNFi monotherapy was used by 399 patients, 229 used TNFi in combination with other immunomodulators, 189 methotrexate monotherapy, 39 vedolizumab, 32 JAKi and 73 patients used other drugs. Patients on rituximab were not included. Patients were vaccinated with Pfizer BNT162b2 (54% patients, 14% controls), Moderna mRNA-1273 (16% patients, 40% controls) or a combination of vaccines (30% patients, 46% controls). Patients received the third vaccine dose a median of 120 (IQR 102-143) days after the second dose. After two doses, median anti-Spike antibody levels were significantly lower in patients (861 BAU/ml (IQR 418-4275) than controls (6318 BAU/ml (IQR 2468-9857)), p<0.001 (Figure 1). Following the third dose, patients achieved antibody levels comparable to the two-dose vaccinated controls (median 5480 BAU/ml (IQR 1081-12069), p=0.28) (Figure 1). In the patients anti-Spike antibody levels increased by a median of 2685 BAU/ml (IQR 265-9129) from the second to the third dose. Main factors associated with increased antibody level after the third dose were younger age (β -87.7 (p=0.002)), and vaccine status (mRNA-1273 vaccine (β 5549 (p<0.001)) or a combination of vaccines (β 4367.3 (p<0.001)).

Adverse events were reported by 438 (48%) of patients after the third dose as compared to 471 (54%) after the second dose and 193 (78 %) of controls. Disease flares were reported by 42 (5%) and 69 (8%) patients after the second and third dose, respectively.

Conclusion

This study suggests that a third vaccine dose for immunosuppressed patients closes the gap in serological response between patients and the healthy population. Antibody levels following the three-dose regimen in IMID patients were comparable to healthy controls vaccinated twice, and no new safety issues emerged. This finding was consistent across all diagnoses and treatment groups, supporting the implementation of a three-dose vaccine regimen as standard in the IMID population.

Disclosure of Interests

Ingrid Jyssum: None declared, Anne Therese Tveter: None declared, Joe Sexton: None declared, Ingrid E. Christensen: None declared, Trung T. Tran: None declared, Siri Mjaaland: None declared, David J Warren: None declared, Tore K. Kvien Speakers bureau: Amgen,Celltrion, Egis, Evapharma, Ewopharma, Hikma, Oktal, Sandoz, Sanofi, Consultant of: Abbvie, Amgen, Biogen, Celltrion, Eli Lilly, Gilead, Mylan, Novartis, Pfizer, Sandoz, Sanofi, Grant/research support from: Grants to institution (Diakonhjemmet Hospital): Abbvie, Amgen, BMS, MSD, Novartis, Pfizer, UCB, Kristin Hammersbøen Bjørlykke: None declared, Grete B. Kro: None declared, Jørgen Jahnsen Speakers bureau: AbbVie, Astro Pharma, Boerhinger Ingelheim, BMS, Celltrion, Ferring, Gilead, Hikma, Janssen Cilag, Meda, MSD, Napp

Pharma, Novartis, Orion Pharma Pfizer, Pharmacosmos, Roche, Takeda, Sandoz, Consultant of: AbbVie, Boerhinger Ingelheim, BMS, Celltrion, Ferring, Gilead, Janssen Cilag MSD, Napp Pharma, Novartis, Orion Pharma, Pfizer, Pharmacosmos, Takeda, Sandoz, Unimedic Pharma, Grant/research support from: Abbvie, Pharmacosmos, Ferring, Ludvig A. Munthe Speakers bureau: Novartis, Cellgene, Espen A Haavardsholm: None declared, John Torgils Vaage: None declared, Gunnveig Grodeland Speakers bureau: Bayer, Sanofi Pasteur, Thermo Fisher, Consultant of: Consulting fees from the Norwegian System of Compensation to Patients and AstraZeneca, Fridtjof Lund-Johansen: None declared, Sella Aarrestad Provan: None declared, Kristin Kaasen Jørgensen Speakers bureau: Roche, BMS, Consultant of: Celltrion, Norgine, Guro Løvik Goll Speakers bureau: AbbVie, Pfizer, UCB, Sandoz, Orion Pharma, Novartis, Consultant of: Pfizer, AbbVie, Silje Watterdal Syversen: None declared

OP0176 THE PERSISTENCE OF ANTI-SPIKE ANTIBODIES FOLLOWING TWO SARS-CoV-2 VACCINES IN PATIENTS WITH IMMUNE-MEDIATED INFLAMMATORY DISEASES USING IMMUNOSUPPRESSIVE THERAPY, COMPARED TO HEALTHY CONTROLS

Background

Limited data is available regarding long-term effectiveness of SARS-CoV-2 vaccines in patients with immune-mediated inflammatory diseases (IMIDs) on immunosuppressive therapy. Whether the persistence of vaccine-induced humoral immunity against SARS-CoV-2 differs between this patient population and the general public is currently unknown.

Objectives

To compare the persistence of anti-Spike antibodies following two SARS-CoV-2 vaccine doses between IMID patients using immunosuppressive medication and healthy controls and identify predictors of antibody decline.

Methods

We included patients with inflammatory joint- and bowel diseases on immunosuppressive medication and healthy controls enrolled in the prospective observational Nor-vaC study. Serum samples were collected at two time points following two dose SARS-CoV-2 vaccination (first assessment within 6–48 days and second within 49–123 days). Sera were analysed for antibodies binding the receptor-binding domain (RBD) of the SARS-CoV-2 Spike protein. Anti-RBD <200 BAU /ml were defined as low levels. The estimated percent reduction in anti-RBD standardised to 30 days was calculated and factors associated with reduction were identified in multivariable regression models.

Results

A total of 1097 patients (400 rheumatoid arthritis, 189 psoriatic arthritis, 189 spondyloarthritis, 129 ulcerative colitis, 190 Crohn´s disease) (median age 54 years [IQR 43–64]; 56% women) and 133 controls (median age 45 years [IQR 35–56]; 83% women) provided blood samples within the defined intervals (median 19 days [IQR 15–24] and 97 days [86–105] after second vaccine dose). Antibody levels were significantly lower in patients compared to controls at both assessments, with median anti-RBD 1468 BAU/ml [IQR 500–5062] in patients and 5514 BAU/ml [2528–9580] in controls (p<0.0001) and 298 BAU/ml [IQR 79–500] in patients and 715 BAU/ml [28–2870] in controls (p<0.0001), at first and second assessment respectively. Figure 1 show antibody levels at both assessments after medication group. At the second assessment, anti-RBD antibody levels decreased below 200 BAU/ml in 452 (41%) patients and in 1 (0.8%) control (p<0.0001) (Table 1). The percentage change in anti-RBD levels were -86 % in patients and -77 % in controls (p<0.0001). The majority of patients using rituximab had low antibody levels at both assessments, Figure 1. In the multivariable regression analyses, patients had a greater decline in anti-RBD levels compared to controls β -3.7 (95% CI -6.0, -1.4) (p<0.001). Use of tumor necrosis factor inhibitors in mono- or combination therapy was associated with the greatest decline compared to controls, β -6.1 (95% CI -8.1, -4.1) and β -6.4 (-8.4, -4.2) respectively (p<0.001).

Table 1.

Serological response in patients and controls

Controls (n=133)Patients (n=1097)Anti-RBD antibodies (BAU/ml)1stassessment2ndassessment1stassessment2ndassessment<5, n (%)0018 (1.6)54 (5)5-19, n (%)004 (0.4)60 (5)20-199, n (%)01 (1)40 (4)338 (31)200-1999, n (%)25 (19)89 (67)548 (50)558 (51)2000-8999, n (%)71 (53)40 (30)398 (36)82 (7.5)≥ 9000, n (%)37 (28)3 (2)89 (8)5 (0.5)

1st assessment 6 - 48 days and 2nd assessment 49 -123 days after second vaccine dose. BAU= Binding antibody Units

Conclusion

Within four months after the second vaccine dose, anti-Spike antibody levels declined considerably in both IMID patients and controls. Patients had lower antibody levels at the first assessment and a more pronounced decline compared to controls, and were consequently more likely to have low antibody levels four months after the second vaccine dose. Our results support that IMID patients lose humoral protection and need additional vaccine doses sooner than healthy individuals.

Disclosure of Interests

Ingrid Egeland Christensen: None declared, Ingrid Jyssum: None declared, Anne Therese Tveter: None declared, Joe Sexton: None declared, Trung T. Tran: None declared, Siri Mjaaland: None declared, Grete B. Kro: None declared, Tore K. Kvien Speakers bureau: Amgen, Celltrion, Egis, Evapharma, Ewopharma, Hikma, Oktal, Sandoz, Sanofi, Consultant of: Abbvie, Amgen, Biogen, Celltrion, Eli Lilly, Gilead, Mylan, Novartis, Pfizer, Sandoz, Sanofi, Grant/research support from: Grants to institution (Diakonhjemmet Hospital): Abbvie, Amgen, BMS, MSD, Novartis, Pfizer, UCB, David Worren: None declared, Jørgen Jahnsen Speakers bureau: AbbVie, Astro Pharma, Boerhinger Ingelheim, BMS, Celltrion, Ferring, Gilead, Hikma, Janssen Cilag, Meda, MSD, Napp Pharma, Novartis, Orion Pharma Pfizer, Pharmacosmos, Roche, Takeda, Sandoz, Consultant of: AbbVie, Boerhinger Ingelheim, BMS, Celltrion, Ferring, Gilead, Janssen Cilag MSD, Napp Pharma, Novartis, Orion Pharma, Pfizer, Pharmacosmos, Takeda, Sandoz, Unimedic Pharma, Grant/research support from: Abbvie, Pharmacosmos, Ferring, Ludvig A. Munthe Speakers bureau: Novartis, Cellgene, Espen Haavardsholm: None declared, John Torgils Vaage: None declared, Gunnveig Grodeland Speakers bureau: Bayer, Sanofi Pasteur, Thermo Fisher, Consultant of: Consulting fees from the Norwegian System of Compensation to Patients and AstraZeneca, Fridtjof Lund-Johansen: None declared, Kristin Kaasen Jørgensen Speakers bureau: Roche, BMS, Consultant of: Celltrion, Norgine, Silje Watterdal Syversen: None declared, Guro Løvik Goll Speakers bureau: AbbVie, Pfizer, UCB, Sandoz, Orion Pharma, Novartis, Consultant of: Pfizer, AbbVie, Sella Aarrestad Provan: None declared

Immunogenicity and Safety of Standard and Third Dose SARS-CoV-2 Vaccination in Patients on Immunosuppressive Therapy

Objective

Immunogenicity and safety following receipt of the standard SARS–CoV‐2 vaccination regimen in patients with immune‐mediated inflammatory diseases (IMIDs) are poorly characterized, and data after receipt of the third vaccine dose are lacking. The aim of the study was to evaluate serologic responses and adverse events following the standard 2‐dose regimen and a third dose of SARS–CoV‐2 vaccine in IMID patients receiving immunosuppressive therapy.

Methods

Adult patients receiving immunosuppressive therapy for rheumatoid arthritis, spondyloarthritis, psoriatic arthritis, Crohn's disease, or ulcerative colitis, as well as healthy adult controls, who received the standard 2‐dose SARS–CoV‐2 vaccination regimen were included in this prospective observational study. Analyses of antibodies to the receptor‐binding domain (RBD) of the SARS–CoV‐2 spike protein were performed prior to and 2–4 weeks after vaccination. Patients with a weak serologic response, defined as an IgG antibody titer of ≤100 arbitrary units per milliliter (AU/ml) against the receptor‐binding domain of the full‐length SARS–Cov‐2 spike protein, were allotted a third vaccine dose.

Results

A total of 1,505 patients (91%) and 1,096 healthy controls (98%) had a serologic response to the standard regimen (P < 0.001). Anti‐RBD antibody levels were lower in patients (median 619 AU/ml interquartile range [IQR] 192–4,191) than in controls (median 3,355 AU/ml [IQR 896–7,849]) (P < 0.001). The proportion of responders was lowest among patients receiving tumor necrosis factor inhibitor combination therapy, JAK inhibitors, or abatacept. Younger age and receipt of messenger RNA–1273 vaccine were predictors of serologic response. Of 153 patients who had a weak response to the standard regimen and received a third dose, 129 (84%) became responders. The vaccine safety profile among patients and controls was comparable.

Conclusion

IMID patients had an attenuated response to the standard vaccination regimen as compared to healthy controls. A third vaccine dose was safe and resulted in serologic response in most patients. These data facilitate identification of patient groups at risk of an attenuated vaccine response, and they support administering a third vaccine dose to IMID patients with a weak serologic response to the standard regimen.

Humoral and cellular immune responses to two and three doses of SARS-CoV-2 vaccines in rituximab-treated patients with rheumatoid arthritis: a prospective, cohort study

BACKGROUND

In rituximab-treated patients with rheumatoid arthritis, humoral and cellular immune responses after two or three doses of SARS-CoV-2 vaccines are not well characterised. We aimed to address this knowledge gap.

METHODS

This prospective, cohort study (Nor-vaC) was done at two hospitals in Norway. For this sub-study, we enrolled patients with rheumatoid arthritis on rituximab treatment and healthy controls who received SARS-CoV-2 vaccines according to the Norwegian national vaccination programme. Patients with insufficient serological responses to two doses (antibody to the receptor-binding domain [RBD] of the SARS-CoV-2 spike protein concentration <100 arbitrary units [AU]/mL) were allotted a third vaccine dose. Antibodies to the RBD of the SARS-CoV-2 spike protein were measured in serum 2-4 weeks after the second and third doses. Vaccine-elicited T-cell responses were assessed in vitro using blood samples taken before and 7-10 days after the second dose and 3 weeks after the third dose from a subset of patients by stimulating cryopreserved peripheral blood mononuclear cells with spike protein peptides. The main outcomes were the proportions of participants with serological responses (anti-RBD antibody concentrations of ≥70 AU/mL) and T-cell responses to spike peptides following two and three doses of SARS-CoV-2 vaccines. The study is registered at ClinicalTrials.gov, NCT04798625, and is ongoing.

FINDINGS

Between Feb 9, 2021, and May 27, 2021, 90 patients were enrolled, 87 of whom donated serum and were included in our analyses (69 [79·3%] women and 18 [20·7%] men). 1114 healthy controls were included (854 [76·7%] women and 260 [23·3%] men). 49 patients were allotted a third vaccine dose. 19 (21·8%) of 87 patients, compared with 1096 (98·4%) of 1114 healthy controls, had a serological response after two doses (p<0·0001). Time since last rituximab infusion (median 267 days [IQR 222-324] in responders vs 107 days [80-152] in non-responders) and vaccine type (mRNA-1273 vs BNT162b2) were significantly associated with serological response (adjusting for age and sex). After two doses, 10 (53%) of 19 patients had CD4+ T-cell responses and 14 (74%) had CD8+ T-cell responses. A third vaccine dose induced serological responses in eight (16·3%) of 49 patients, but induced CD4+ and CD8+ T-cell responses in all patients assessed (n=12), including responses to the SARS-CoV-2 delta variant (B.1.617.2). Adverse events were reported in 32 (48%) of 67 patients and in 191 (78%) of 244 healthy controls after two doses, with the frequency not increasing after the third dose. There were no serious adverse events or deaths.

INTERPRETATION

This study provides important insight into the divergent humoral and cellular responses to two and three doses of SARS-CoV-2 vaccines in rituximab-treated patients with rheumatoid arthritis. A third vaccine dose given 6-9 months after a rituximab infusion might not induce a serological response, but could be considered to boost the cellular immune response.

FUNDING

The Coalition for Epidemic Preparedness Innovations, Research Council of Norway Covid, the KG Jebsen Foundation, Oslo University Hospital, the University of Oslo, the South-Eastern Norway Regional Health Authority, Dr Trygve Gythfeldt og frues forskningsfond, the Karin Fossum Foundation, and the Research Foundation at Diakonhjemmet Hospital.