Because of a lapse in government funding, the information on this website may not be up to date, transactions submitted via the website may not be processed, and the agency may not be able to respond to inquiries until appropriations are enacted.

Updates regarding government operating status and resumption of normal operations can be found at

NIH HIV Vaccine (NACHO) Study

Study Name

Phase I Study of Safety and Immunogenicity of Ad4-HIV Vaccine Vectors in Healthy Volunteers

Study Number


Goal of Study

The purpose of this study is to test experimental HIV vaccines to see if they are safe. HIV (human immunodeficiency virus) is the virus that causes AIDS (acquired immune deficiency syndrome). The vaccines use a live adenovirus as a carrier (or transporter). Adenoviruses are naturally occurring viruses that typically cause symptoms of a cold or conjunctivitis (a superficial eye infection). We hope that the adenovirus carrier will help the vaccines stimulate an immune response against HIV. An immune response is the body’s release of cells and substances that protect the body from infection and foreign matter. Another important goal is to see whether different ways of giving the vaccines cause different immune responses. We also want to see if the adenovirus in the vaccines is contagious or spreads to others. The study vaccine will not expose you to HIV infection. Volunteers will be compensated.

Study Regimen

We plan to enroll up to 110 subjects who are 18 to 49 years old and in good general health. We estimate that an additional 110 household or intimate contacts will be enrolled in this study. The study vaccine is sprayed in the nose. You must be willing to be hospitalized for between 5 to 7 days, or longer if needed for medical reasons, since the vaccines contain a live adenovirus. There is a possibility that you can infect other people with adenovirus. Therefore, all of your intimate contacts must join this study. An intimate contact is someone you will kiss on the mouth, have intercourse with, or have oral sex with during the study. You will be asked to talk to your intimate contacts about your plans to participate in this study. If you want to participate, your intimate contacts will need to notify the study team and set up a discussion about the study and their potential participation.

Your household contacts may also participate in this study. A household contact is anyone that you live in the same house or apartment with. We will ask you to discuss this study with your household contacts and ask them to contact the study team if they are interested in participating. Your household contacts do not have to participate in this study for you to participate.

Your total time of participation in this study will be 14 months. During this time, you will have one 7-day hospital stay, 2 additional vaccination visits, and 7 follow-up visits. You may need additional follow-up visits if you experience adenovirus symptoms or vaccine side effects. You will be monitored throughout the study for vaccine-related side effects and treated at the NIH hospital in case any occur.

Risk of Positive Future HIV Tests

At the time you enroll in the study you must have a negative HIV antibody test. An HIV antibody test is the usual way to test for HIV infection. After the study vaccinations, it is very likely that you will have a positive result on common HIV tests that look for antibody. If you get an HIV test somewhere else, people giving the test may think you have HIV infection. For this reason, you should get HIV tests only at the NIH during the study. We will use a testing method that looks for the presence of HIV virus. This method will show if a true infection is present.

We do not know how long HIV antibodies from the experimental vaccinations will last in your blood. When this study finishes, we can assist you with obtaining tests that can tell the difference between antibody from study vaccinations and a true HIV infection. This can be done either by testing in another NIH research protocol or by advising your private healthcare provider on testing methods.

If someone believes you have HIV infection when you do not, then you could face discrimination. For example, you could be denied health care, employment, insurance, a visa, or entry into the military. You may also call the clinic if you need assistance or have questions or concerns.

It is important for you to continue to avoid behaviors associated with the risk of getting HIV infection.

Eligibility Criteria

  • You are you 18-49 years old.
  • You are HIV-negative, and willing to have an HIV test at your screening visit.  (Note:  A positive HIV test at screening will abide by the NIH guidelines for sexual partner notification.)
  • You can you commit to a one-week stay at NIH.
  • If female, you are not pregnant or breast-feeding and you do not plan on becoming pregnant in the near future.
  • All of the following are true: You do NOT live with anyone with a weakened immune system; live with anyone with a chronic illness; live with or care for anyone under 18 years old; or live with anyone who is pregnant or planning to become pregnant.
  • You are not a healthcare worker.
  • You live in the DC Metro area and are you able to travel to Bethesda, Maryland, for the study.
  • You are willing to answer personal questions regarding drug use, alcohol use, and sexual history​.
Content last reviewed on March 21, 2016