Background and Importance The effectiveness and safety of COVID-19 vaccines has been demonstrated in the pivotal trials that have led to their approval. However, there is no specific information available regarding COVID-19 vaccination in patients with immune-mediated diseases (IMD).

Aim and Objectives Evaluate the effectiveness and safety of COVID-19 vaccines in patients with IMD who are being treated with biological drugs (BD).

Material and Methods Prospective descriptive observational study of patients with IMD treated with BD who have received at list one dose of any of the COVID-19 vaccines commercialised.

Variables collected: age, sex, IMD, BD, post-vaccination COVID-19 infection, adverse reactions observed after vaccination.

Demographic and clinical data were obtained from the medical records.

To assess effectiveness, we checked the number of patients who became infected with SARS-CoV-2 after vaccination and whether the infection was asymptomatic, with mild symptoms or required hospital admission.

To assess safety, a standardised interview of adverse reactions observed in the first seven days after COVID-19 vaccination was conducted during routine pharmacy practice.

This study was approved by the Ethics Committee of Research with Medicines under code: 2021/435.

Results 106 patients (52.8% female) were included, with a median age of 53 years (21-76). The most frequent IMD were: rheumatoid arthritis (33%), psoriatic arthritis (15%), psoriasis (15%) and Crohn’s disease (11.3%). The most commonly used BDs were: adalimumab (33.9%), etanercept (25.5%), abatacept (7.5%), ixekizumab (6.6%), secukinumab (6.6%), golimumab (5.7%) and ustekinumab (4.7%).

Twenty-two patients (20.75%) were infected after receiving doses of COVID-19 vaccines: 2 after the first dose, 6 after the second dose and 14 after the third dose. Infected patients had mild symptoms (77.3%) or were asymptomatic (22.7%). No patient required hospital admission.

The most common adverse reactions were: pain at the injection site (79.2%), fatigue (48%), malaise (42.4%), myalgia (35.8%), headache (33%), arthralgia (25.5%), fever (21.7%), pruritus (11.3%), nausea or vomiting (9.4%), and lymphadenopathy (9.4%).

Conclusion and Relevance 79.25% of the patients studied were not infected with SARS-CoV-2 after vaccination. Most of the infected patients had mild symptoms and none of them required hospital admission.

Adverse reactions were similar to those described in the general population, the most frequent being pain at the injection site, fatigue and malaise.

COVID-19 vaccines were effective and safe in patients with IMD treated with BD included in the study.

Conflict of Interest No conflict of interest.