Community health workers (CHW) can play an active role in providing integrated HIV and harm reduction services. We used social media to create a virtual network among Vietnamese CHW. This paper reports CHW's social media engagement and the relationships with other work-related indicators. Sixty CHW participated in an intervention for integrated HIV/drug use service delivery. Following two in-person sessions, Facebook groups were established for CHW to share information, seek consultation, and refer patients. CHW's levels of online engagements were tracked for six months and linked to their service provision confidence, interaction with patients and other providers, and job satisfaction. The CHW made 181 posts, which received 557 comments and 1,607 reactions during the six months. Among the 60 CHW, 22 (36.6%) had three or more posts, 19 (31.7%) had one or two posts, and 19 (31.7%) had no post. Comparing the baseline and 6-month follow-up data, we observed that those who posted three or more times showed better service provision confidence (p = 0.0081), more interaction with providers in other settings (p = 0.0071), and higher job satisfaction (p = 0.0268). Our study suggests using social media to engage CHW in virtual communications to improve service provision in communities.