To the editor
Between the end of 2020 and the beginning of 2021, the first mRNA vaccines against COVID-
19 received approval for emergency use by the World Health Organization (WHO). Patients
affected by fibrotic interstitial lung disease (ILD) were granted priority access to vaccination,
as these patients may develop severe complications after SARS-CoV-2 infection and carry a
higher risk of death, with in-hospital mortality estimated to be around 50%.
Acute exacerbations of idiopathic pulmonary fibrosis (AE-IPF) are defined as acute, clinically
significant respiratory deteriorations characterized by new bilateral ground-glass
opacification/consolidation at chest imaging not fully explained by cardiac failure or fluid
overload. These events are characterized by poor prognosis and have limited therapeutic
options. A role for viral infections – including SARS-CoV-2 – as triggers of acute exacerbation
of ILD has been suggested, although the pathobiological mechanisms driving the acute lung
injury remains largely unknown (5)(6). Cases of acute interstitial pneumonia or exacerbation
of existing fibrosing ILD developed after vaccination for influenza viruses such as H1N1 have
also been reported in the past (7)(8), however there is limited knowledge about the risk of
these events in relation to COVID-19 vaccination..