This Week In Wellness research published in the journal Scientific Reports showed that infants who spent most of their first year of life during the pandemic have fewer types of bacteria in their gut than infants born prior to the pandemic.

https://www.news-medical.net/news/20230831/Pandemic-may-have-altered-gut-microbiome-of-infants-study-finds.aspx

https://www.nature.com/articles/s41598-023-40102-y