COVID-19 in the absence of eosinophils: a case series of confirmed infection whilst on treatment with benralizumab

ABSTRACT

BackgroundBlood eosinopaenia was one of the earliest reported findings in hospitalised patients with COVID-19, questioning whether eosinophils could have an anti-viral or deleterious role in the immune response against SARS-CoV2. Benralizumab is an anti-IL5R monoclonal antibody licensed for the treatment of severe eosinophilic asthma (SEA) and causes the near-complete depletion of blood and tissue eosinophils. As such, it offers the opportunity to explore the impact of eosinopaenia at the time of infection on outcome with COVID-19.MethodPatients started on treatment with benralizumab (up until April 2021) for SEA at our regional asthma centre were contacted by telephone throughout May and June 2021 to establish whether they had experienced a confirmed (PCR-positive) SARS-CoV2 infection since commencing benralizumab. Clinical and demographic characteristics were recorded along with the outcome of infection, including the need for hospitalisation or intensive care admission. Patients requiring hospitalisation were compared to those experiencing mild infections.ResultsData on 268 patients treated with benralizumab was collected with 24/268 (9%) confirming SARS-CoV2 infection with a positive PCR test. Of these 18/24 (75%) experienced mild infections that did not require hospitalisation. Of the 6/24 requiring hospitalisation, the median (IQR) length of stay was 6 (1–8) days. No patients required ICU admission or mechanical ventilation. There was no significant difference in baseline characteristics between hospitalised and non-hospitalised patients. However, it is noteworthy that a higher proportion of hospitalised patients were male (50.0% vs 38.9%) and had a higher mean BMI (32.1 vs 29.5).DiscussionIn the context of drug-induced eosinopaenia with benralizumab, 75% of patients with severe asthma experienced mild COVID-19 disease. This is likely to be an underestimate given that other patients may have experienced an asymptomatic infection or not pursued PCR testing in the context of mild infection. Although caution is needed due to the small sample size, these results do not support a significant role for eosinophils in SARS-CoV2 infection.