A Clinical Trial to Evaluate Safety, Tolerability, and Immunogenicity of Adjuvanted HIV-1 Fusion Peptide Conjugate Vaccine Alone or in Prime-Boost Regimens With Adjuvanted HIV-1 Envelope Trimer 4571 and HIV-1 Trimer 6931 Vaccines in Healthy Adults

1. Active duty and reserve US military personnel.

2. Breast-feeding or planning to become pregnant from at least 21 days prior to enrollment through 12 weeks after the last product administration.

3. An investigational HIV vaccine (previous placebo recipients are not excluded).

4. Immunosuppressive medications received within 168 days before first vaccination (Not exclusionary: \[1\] corticosteroid nasal spray; \[2\] inhaled corticosteroids; \[3\] topical corticosteroids for mild, uncomplicated dermatologic condition; or \[4\] a single course of oral/parenteral prednisone or equivalent at doses ≤ 60 mg/day and length of therapy \< 11 days with completion at least 30 days prior to enrollment).

5. Blood products within 60 days prior to enrollment

6. Monoclonal antibodies (mAbs), whether licensed or investigational. Exceptions may be made by the HVTN 303 PSRT on a case-by-case basis

7. Receipt of any of the following:

* Within 4 weeks prior to enrollment:

* Any licensed live, attenuated vaccine

* Any adenoviral-vectored SARS-CoV-2 vaccine with FDA Emergency Use Authorization (EUA), FDA licensure or World Health Organization (WHO) Emergency Use Listing (EUL)

* Within 2 weeks prior to enrollment:

* Any licensed killed/subunit/inactivated vaccine

* Any mRNA based or protein SARS-CoV-2 vaccines with FDA EUA, FDA licensure, or WHO EUL

8. Investigational research agents with a half-life of 7 or fewer days within 4 weeks prior to enrollment. If a potential participant has received investigational agents with a half-life greater than 7 days (or unknown half-life) within the past year, PSRT approval is required for enrollment.

9. Current allergen immunotherapy with antigen injections, unless on maintenance schedule.

10. Current anti-TB prophylaxis or therapy.

11. Serious adverse reactions to vaccines or vaccine components.

12. Hereditary angioedema, acquired angioedema, or idiopathic forms of angioedema.

13. Hypertension that is not well controlled.

14. Asthma is excluded if the participant has ANY of the following:

* Required either oral or parenteral corticosteroids for an exacerbation two or more times within the past year; OR

* Needed emergency care, urgent care, hospitalization, or intubation for an acute asthma exacerbation within the past year (eg, would NOT exclude individuals with asthma who meet all other criteria but sought urgent/emergent care solely for asthma medication refills or co-existing conditions unrelated to asthma); OR

* Uses a short-acting rescue inhaler more than 2 days/week for acute asthma symptoms (ie, not for preventive treatment prior to athletic activity); OR

* Uses medium-to-high-dose inhaled corticosteroids (greater than 250 mcg fluticasone or therapeutic equivalent per day), whether in single-therapy or dual-therapy inhalers (ie, with a long-acting beta agonist \[LABA\]); OR

* Uses more than one medication for maintenance therapy daily. Inclusion of anyone on a stable dose of more than one medication for maintenance therapy daily for greater than two years requires PSRT approval.

15. Autoimmune disease, current or history, including psoriasis.

16. Clinically significant immunodeficiency.

17. AESIs: Volunteers who currently have, or have a history of, any condition that could be considered an AESI for the product(s) administered in this protocol.

18. History of generalized urticaria, angioedema, or anaphylaxis. (Not exclusionary: angioedema or anaphylaxis to a known trigger with at least 5 years since last reaction to demonstrate satisfactory avoidance of trigger.).

19. Diabetes mellitus type 1 or type 2.

20. Bleeding disorder diagnosed by a doctor (eg, factor deficiency, coagulopathy, or platelet disorder requiring special precautions) or significant bruising or bleeding difficulties with IM injections or blood draws.

21. Seizure disorder other than: 1) febrile seizures, 2) seizures secondary to alcohol withdrawal more than 3 years ago, or 3) seizures that have not required treatment within the last 3 years.

22. Asplenia or functional asplenia.

23. Malignancy (Not excluded from participation: Volunteer who has had malignancy excised surgically and who, in the investigator's estimation, has a reasonable assurance of sustained cure, or who is unlikely to experience recurrence of malignancy during the period of the study).

24. Any other chronic or clinically significant condition that in the clinical judgement of the investigator would jeopardize the safety or rights of the study participant, including, but not limited to: clinically significant forms of drug or alcohol abuse, serious psychiatric disorders, or cancer that, in the clinical judgement of the site investigator, has a potential for recurrence (excluding basal cell carcinoma).

What this study is about