This is an ancillary study, thus participants will be recruited from participants in the HBS Study. This project acutely assesses the role of the e-cigarettes and vaping on lung health. The proposed work will inform the design of future studies to better understand vaping's health consequences and to test novel interventions to mitigate vaping's contribution to acute and/or chronic lung injury.

This project is an ancillary study to the HBS Study. Inclusion Criteria for that IRB approved study are:

• documented HIV-infection
• in care at an HIV specialty clinic
• age ≥ 18 years.

Exclusion criteria for the HBS Study are:

• a pacemaker or other implanted electronic device
• pregnant women, prisoners, cognitively-impaired subjects.

For this ancillary, the experimental group must actively use at least one of the following: e-cigarettes, e-liquid vapes, burning leaf tobacco cigarettes, or inhaled burning leaf marijuana (cannabis). The control group will have no use of e-cigarettes or vape or active smoking in the past year.

Participants must be willing to archive data and biological samples for future use.

Exclusion from the ancillary are:

• overt respiratory or oral cavity disease
• acute illness in the past 4 weeks
• active cancer
• active weight loss program
• any other medical, psychiatric or behavioral factors that, in the judgment of the PI may interfere with study participation or ability to follow the protocol

People living with HIV (PLWH) in the study site areas who are enrolled in the HBS study (main trial).