Background Social media (SoMe) is ubiquitous, but its adoption and utilization by infectious diseases (ID) divisions are poorly characterized. Methods A systematic search of US ID fellowship/division Twitter, Facebook, and Instagram accounts occurred in November-December 2021. SoMe account and program characteristics, post frequency and content, and other measures of SoMe adoption and utilization were recorded and compared between adult and pediatric programs. Posts were thematically categorized as social, promotional, educational, recruitment, or other. Results Of 222 ID programs identified, 158 (71.2%) were adult and 64 (28.8%) pediatric. 70 (31.5%) Twitter, 14 (6.3%) Facebook, and 14 (6.3%) Instagram accounts were identified from US programs. Twitter accounts were associated with larger programs and higher match rates. More adult than pediatric programs had Twitter accounts (37.3% vs. 17.2%, p=0.004); utilization was similar between adult and pediatric programs. Most Twitter posts were educational (1653/2859, 57.8%); Facebook promotional (68/128, 53.1%); Instagram social (34/79, 43%). Facebook was the earliest adopted SoMe platform, but Twitter and Instagram have more recent growth. Rate of Twitter account creation increased from 1.33 accounts/month in the year prior to March 2020 (COVID pandemic declaration) to 2.58 accounts/month in the year after March 2020 (p=0.18). Conclusion SoMe remains underutilized across ID divisions, but COVID-19 and virtual recruiting may have influenced recent account creation. Twitter was the most frequently used ID program SoMe platform. SoMe may benefit ID programs in recruitment and amplification of their trainees, faculty, and specialty.