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Vaccine Induced Sero-Positivity /Sero-Reactivity in participants of HIV vaccine clinical trials:

Which term to use?

A consultation organized by the Global HIV Vaccine Enterprise led to the finding that it may not be possible or even practical at this time to seek a single term to use across the field of HIV Vaccine to describe the antibody response to HIV vaccine candidates that may be detected by diagnostic assays. It may be more desirable to discriminate between several terms that coexist and leave the choice to the user depending on the context and the audience. Here we review some existing and suggested terms and identify the nuances in potential use and applicability to various situations.

None of these terminologies is HIV vaccine specific per se; each can be qualified by adding the
prefix ‘HIV- ‘

There was strong consensus that when publishing about the issue, no matter what term is being used in the narrative or in practice, it will be important to refer to the terms VISP and VISR, at least in footnotes, to allow for bibliographical searches and cross-references.


Vaccine-Induced Sero-positivity (VISP)

Pros
:   

  • Accurately refers to the fact that some antibodies created in response to a vaccine candidate will be detected in the blood of trial participants by commercially available serologically-based tests. These are not ‘false-positives’ as the tests are accurately identifying circulating antibodies to HIV. In that situation, the participant is ‘sero-positive’ even without infection.
  • Currently, the most commonly used and best-known term, including scientific publications and the Wikipedia page.
  • Widely used by the HVTN protocols and lab reports as well as in materials for enrollment and training.

Cons:

  • The word ‘positivity’ may be misunderstood and associated with being HIV positive, leading to stigmatization and social harm. This concern was highlighted by community representatives in focus group consultations and surveys. There are mixed reports on the frequency of this problem from organizations that have been using VISP in materials oriented to volunteers and community representatives.
  • The word ‘sero-‘may not be understood by non-scientists/non-clinicians.

Summary:

Best used when continuity with previous literature is important and when the audience is less likely to misunderstand or be put off by the term.   


Vaccine-Induced Sero-Reactivity (VISR)

Pros:

  • Currently in use (HVTN diagnosis laboratories; MHRP informed consent forms)
  • “-Reactivity” is considered to be more accurate than ‘-positivity’ when describing lab assays or results. The word “reactivity’ refers to a specimen submitted to a specific assay and not to the individual from which the specimen comes from.

Cons:

  • The word “Reactivity” may not be well understood by non-scientists; it may have a negative connotation for some people and be associated with the risk of having a ‘bad reaction’ to an administered substance.
  • As above, the word ‘sero-‘may be obscure for non-scientists/non-clinicians.

Summary:
Best used with well-informed audience and when referring specifically to test results and assays.


Vaccine-induced Antibodies

Pros:
 

  • In polls and surveys, this term received the most support among community partners.
  • The concept of antibodies is generally well understood and accepted as a desirable outcome.

Cons:

  • The term does not refer to testing and, therefore, may not raise awareness of the fact that diagnostic testing may be confused by these antibodies.
  • Does not distinguish between antibodies that do or do not react with a diagnostic test.
  • The word “-induced” may have a negative connotation for some audiences.

Summary:

Best used with a lay audience. Can be used to refer to diagnostic test results if it has been made very clear that ‘Antibodies’ in this context refer to the fraction that is reactive with the test being used.

This term can also be used when referring to antibody response in general (not just to antibodies that react with the diagnostic test).

The two possible uses of the term should be dictated by the context and should not be mixed within the same conversation.


Vaccine Antibody Response

Pros:

  • This term received a lot of support in polls and community surveys.
  • As above, the concept of making antibodies is generally well understood and accepted as a desirable outcome.
  • Simple and non-threatening’ language; the word ‘Induced” that can be perceived as a negative occurrence by some audiences is being avoided in this terminology.

Cons:

  • The term does not refer to testing and, therefore, may not raise awareness of the fact that diagnostic testing may be confused by these antibodies.
  • Does not distinguish between antibodies that do or do not react with a diagnostic test.

Summary:

As with “Vaccine-Induced Antibodies”, this term is best used with a lay audience or when referring to antibody response in general. It should not be used in situations when general antibody response can be confused with only the fraction of antibodies reactive with diagnostic tests.


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