PurposeGranuloma and delayed inflammatory reaction to hyaluronic acid (HA) facial esthetic fillers occurs rarely. More recently, these reactions have been reported with increasing frequency and have been associated with COVID-19 infection. The purpose of the study is to determine if delayed filler granulomas are more common after the start of the COVID-19 pandemic.MethdosA retrospective cohort study including of all patients treated with dermal filler at 4 offices of a single cosmetic surgery practice between August 1st, 2018 and October 31st, 2021 was performed. The primary outcome variable was granuloma formation. The primary predictor variable was time period, either pre-COVID (8/1/18-2/29/20) or post-COVID (3/1/20-10/31/21). Other study variables recorded were age, amounts of dermal fillers used, and types of dermal filler used. Data was analyzed using chi-squared, t-tests and logistic regression.ResultsOver the study period, 3,255 patients receiving 8,067 syringes of filler over 6,800 sessions were reviewed. The average patient age was 46.8 ± 13.7 years and 2,583 sessions were performed in the pre-COVID time period and 4,217 sessions in the post-COVID time period. There were 11 granulomas in 9 subjects receiving filler in the post-COVID time period and 0 granulomas in the pre-COVID time period (0.3% vs 0.0%, respectively, p = 0.009). Juvederm Vollure was used in 64% of patients who developed granulomas, but only accounted for 26% of filler administrations in the post-COVID time period and 28% in the cohort overall (p=0.02).ConclusionGranuloma formation is a rare complication of HA filler injection that appears to be occurring with more frequency following the COVID-19 pandemic. Practitioners who administer dermal fillers should be aware of this complication and its apparent increased incidence