Infliximab is associated with attenuated immunogenicity to BNT162b2 and ChAdOx1 nCoV-19 SARS-CoV-2 vaccines

Evidence before this study

Faced with further surges of SARS-CoV-2 infection, a growing number of countries, including the UK, have opted to delay second vaccine doses for all people. This strategy trades maximal effectiveness against a lower level of protective immunity across more of the at-risk population.

We have previously shown that seroprevalence, seroconversion in PCR-confirmed cases, and the magnitude of anti-SARS-CoV-2 antibodies following SARS-CoV-2 infection are reduced in infliximab-compared with vedolizumab-treated patients. Whether single-doses of vaccines are effective in patients treated with anti-TNF therapies is unknown.

We searched PubMed from 25 November 2019 to 23 March 2021 with the terms “anti-tumour necrosis factor” or “anti-integrin” or “infliximab” or “adalimumab” or “vedolizumab” or “biological therapy” or “biologic therapy” AND “SARS-CoV-2” or “coronavirus” or “COVID-19” or AND “seroprevalence” or “seroconversion” or “antibody” or “antibody response” or “magnitude” or “immunogenicity” AND “vaccine” or “vaccination” or “immunisation” or “immunization” or “ChAdOx1 nCoV-19” or “BNT162b2” or “mRNA-1273”, without restriction on language.

Serological responses to SARS-CoV-2 vaccines have been reported in registration trials and small observational cohorts of healthy volunteers. Two small studies, including one unpublished preprint, found that COVID-19 vaccine immunogenicity rates were lower in transplant recipients and patients with malignancy receiving immunosuppressive therapy, and fewer patients treated with potent immunosuppressants seroconverted than healthy controls. No studies have assessed the effect of anti-TNF therapy on immunogenicity following SARS-CoV-2 vaccination.

Added value of this study

To test if anti-TNF drugs attenuate serological responses to primary SARS-CoV-2 vaccines, we analysed anti-SARS-CoV-2 spike (S) antibody concentrations and seroconversion rates in 1293 patients with inflammatory bowel disease who received primary vaccinations with either the ChAdOx1 nCoV-19 or BNT162b2 vaccines. 865 were treated with the anti-TNF drug infliximab and outcomes were compared to a reference cohort of 428 patients treated with vedolizumab, a gut selective anti-integrin α4β7 monoclonal antibody that is not associated with impaired systemic immune responses.

Anti-SARS-CoV-2 antibody levels and rates of seroconversion were lower following primary vaccination with both the BNT162b2 and ChAdOx1 nCoV-19 vaccines in patients with IBD treated with infliximab compared to vedolizumab. Older age, immunomodulator use, Crohn’s disease (versus ulcerative colitis or inflammatory bowel disease unclassified), and current smoking were associated with lower anti-SARS-CoV-2 antibody concentrations, irrespective of vaccine type. Non-white ethnicity was associated with higher anti-SARS-CoV-2 (S) antibody concentrations following primary vaccination with both vaccines. Antibody concentrations and seroconversion rates were higher in patients with past SARS-CoV-2 infection prior to a single-dose of either vaccine, and after 2 doses of the BNT162b2 vaccine.

Implications of the available evidence

Our findings have important implications for patients treated with anti-TNF therapy, particularly for those also treated with an immunomodulator. Poor antibody responses to a single-dose of vaccine exposes these patients to a potential increased risk of SARS-CoV-2 infection. However, higher rates of seroconversion in patients with two exposures to SARS-CoV-2 antigen, even in the presence of TNF blockade, suggest that all patients receiving these drugs should be prioritized for optimally timed second doses. Until patients receive a second vaccine dose, they should consider that they are not protected from SARS-CoV-2 infection and continue to practice enhanced physical distancing and shielding if appropriate. Even after two antigen exposures, a small subset of patients failed to mount an antibody response. Antibody testing and adapted vaccine schedules should be considered to protect these at-risk patients.