COVID-19 infection relatively rare in vaccinated IBD patients

Patients with inflammatory bowel disease (IBD) who have completed a COVID-19 vaccine regimen have a low risk of developing COVID-19, though receipt of mRNA vaccines may offer better protection, according to a small study presented at the Crohn’s and Colitis Congress 2022.

While COVID-19 vaccines are effective in patients with IBD, vaccination does not completely rule out infection, said study author Emily Spiera, a medical student at Icahn School of Medicine at Mount Sinai, New York, New York, US.

“[This study showed that] vaccinated patients who subsequently developed COVID-19 had low rates of hospitalization, severe COVID-19, and death,” she continued.

Spiera and co-authors used data from the Surveillance Epidemiology of Coronavirus Under Research Exclusion in Inflammatory Bowel Disease (SECURE-IBD) database which comprises data of patients with IBD from 74 countries. Of these, 2,477 were diagnosed with COVID-19 between December 12, 2020 and October 1, 2021, of whom 160 had been vaccinated (53 partially vaccinated*).

Eighty-eight patients with IBD who had completed** a primary vaccination series prior to laboratory-confirmed diagnosis of COVID-19 were included (average age 40.1 years, 54.7 percent female, 89.7 percent White). The vaccines received could be the mRNA (Pfizer, Moderna), adenovirus vector (CanSino, AstraZeneca, Sputnik, Janssen), or inactivated SARS-CoV-2 (Sinovac) vaccines. The most common vaccine in this cohort was the Pfizer mRNA vaccine (65.9 percent). Fifty-nine percent of patients had Crohn’s disease.

Compared with the 2,317 patients who were not vaccinated, those with complete vaccination status had a numerically lower hospitalization rate (5.7 percent vs 9.3 percent [n=5 vs 216]; p=0.25). [Crohn’s and Colitis Congress 2022, session 46; Inflamm Bowel Dis 2022;28 Suppl 1:S104-S105]

The differences between vaccinated and non-vaccinated patients in terms of severe COVID-19 disease*** and death were smaller, which the researchers suggested was due to small sample size (3.4 percent vs 1.9 percent [n=3 vs 43]; p=0.24 for severe COVID-19 and 1.1 percent vs 1.2 percent [n=1 vs 29]; p=0.94 for mortality).

“When stratified by vaccine mechanism, we saw a numeric advantage with mRNA vaccines,” presented Spiera.

Patients who received the mRNA vaccine had lower hospitalization rates compared with those who received non-mRNA vaccines (2.9 percent vs 16.7 percent; p=0.06), as well as lower rates of severe COVID-19 (1.4 percent vs 11.1 percent; p=0.11).

Fifty-eight percent of patients were on biologic monotherapy, primarily tumour necrosis factor (TNF) antagonists (38.6 percent), 3.4 percent were on immunomodulator monotherapy, 21.6 percent on combination therapy, and 5.7 percent on corticosteroids.

“When comparing IBD medications, we saw that patients on combination therapy had the poorest outcomes,” said Spiera.

Hospitalization rate was highest in patients on combination therapy compared with those on immunomodulator therapy or biologic monotherapy (15.8, 0, and 2.0 percent, respectively). Two patients (10.5 percent) on combination therapy had severe COVID-19 compared with none on immunomodulator therapy or biologic monotherapy. The one death occurred in a 63-year-old woman with moderately active Crohn’s disease who was on corticosteroids, adalimumab, and azathioprine, and who received a non-mRNA COVID-19 vaccine >30 days before COVID-19 infection.

Consistent with observations in the general population, age had a part to play in the outcomes with a significantly higher risk of hospitalization among those with a mean age of 53 vs 39 years (p=0.04), and a higher risk of severe COVID-19 among those with a mean age of 59 vs 39 years (p=0.03).

“Our findings support prior studies showing that combination therapy and TNF antagonist use may result in blunted immunity that wanes. [The results are also] consistent with trends suggesting mRNA vaccines may provide better protection in patients with IBD,” Spiera concluded.

Spiera emphasized that the results were based on small event numbers and sample size and as such, the comparisons were not statistically significant. In addition, the analysis was based on patients with known COVID-19 disease and medication use for IBD was documented at time of infection and may have differed at time of vaccination. The study was also conducted prior to the emergence of the omicron variant.