An update and overview of the literature on late inflammatory reactions (LIRs) in soft tissue fillers after SARS-CoV-2 infection and vaccination

Introduction: Soft tissue fillers are widely used and are commonly considered to be safe. Nonetheless, adverse events such as late inflammatory reactions (LIRs) are reported for every type of filler. As of the start of the COVID-19 pandemic, LIRs have been reported after SARS-CoV infection or vaccination. In the past, we reviewed these adverse events; however, since then, we faced a wave with the Omicron, and the vaccination programs continued with booster vaccines. We therefore aimed to perform an up-to-date review of the literature on LIRs after COVID-19 infection and vaccination with additional learned lessons from this pandemic. Material and methods: We performed a systematic review on soft tissue filler-related LIRs after SARS-CoV-2 infection or vaccination in line with the PRISMA guidelines. Eligible studies were searched in the database PubMed from 1 August 2021 until 1 June 2023. Data on patient characteristics, filler characteristics, clinical findings, and treatment options were retrieved. Results: A total of 14 papers with in total 52 patients were reported, of which 16 had adverse events after a SARS-CoV-2 infection and 36 after SARS-CoV-2 vaccination. In most cases, it concerned females who had their (mostly temporary) fillers for cosmetic purposes. Symptoms were reported in a matter of hours up to weeks after SARS-CoV-2 vaccination (22 Pfizer, 7 Moderna, 3 AstraZeneca, 3 Sputnik V, and one after Siophram), mostly after the first or second dose but sporadically after a third dose. Most patients were treated in a conservative manner. Discussion: LIRs continue to be reported after SARS-CoV-2 infection and vaccination and are currently also reported for non-mRNA vaccines, for non-temporary fillers, and also after a third dose of the vaccine. Although there are more and more papers on this matter, they remain minor and self-limiting. We therefore still advise patients with soft tissue fillers to remain participated in vaccination programs when needed. Level of evidence: Not gradable.