Opioid, HIV and Immune System

Inclusion criteria

For Opioid (OP) users/non-users:

• OP users - prescribed opioids for at least the past 90 days; or injecting opioids for at least 90 days
• Opioid never-users in the past year

Additional criteria for OP users:

• OP use for 90 days pre-flu vaccination
• Continued OP use for 4 weeks post flu vaccination

For HIV positive participants:

• HIV infection, as documented by any licensed ELISA kit and confirmed by Western blot at any time prior to study entry. Participants on ART as a result of prior HIV documented infection will not be required to provide proof of diagnosis of HIV infection.

Additional criteria for HIV positive participants:

• On ART for at least 1 year with plasma pending viral load (VL) <200 copies/mL. Occasional viral blips up to 1000 copies/ml also acceptable provided the patients are on continuing treatment
• CD4 count available in the prior 6 months and >200/mm3
• Undetectable viral load (< 200 copies/mL)

For HIV negative participants:

• Documented negative HIV test, either by any licensed ELISA or rapid tests within the past 6 months.

For all participants:

• Individuals age 18-60 yrs .
• No history of other immunodeficiency disorders
• Not on steroid or other immunosuppressive/immunomodulators medications.
• No active malignancies.
• No contraindication to receive influenza vaccination (allergy to chicken eggs or to any other substance of the vaccine).
• Agreeable to receive the influenza vaccination.
• Agreeable to participate in study for a complete course of study full visits.
• Able to provide informed consent.

Exclusion criteria

• Contraindication to receive influenza vaccination (allergy to chicken eggs or to any other substance of the vaccine).
• Non-adherence to ART for HIV+
• Unable to provide informed consent.
• Other comorbid conditions such as diabetes mellitus type 2 (DMT2)
• Influenza vaccination already given during the current vaccination season.