The reference doesn't directly state "OPA vaccine," but uses the abbreviation "OPA" in the context of measuring immune responses. Therefore, the question is slightly misleading. Here's a breakdown based on the information provided:
The reference discusses the accelerated approval of a vaccine to prevent pneumonia caused by S. pneumoniae serotypes 8, 10A, 11A, 12F, 15B, 22F, and 33F. The approval is based on immune responses measured by opsonophagocytic activity (OPA) assay. Thus, OPA, in this context, stands for opsonophagocytic activity, and it refers to a type of assay used to assess the effectiveness of the vaccine in generating an immune response. It is not itself a type of vaccine. The OPA assay measures the ability of antibodies to promote the engulfment and killing of bacteria by phagocytic cells.
Here's a table summarizing the key information:
| Abbreviation | Full Form | Context |
|---|---|---|
| OPA | Opsonophagocytic Activity | A measure of the functional antibody response induced by a vaccine, specifically the ability of antibodies to promote the engulfment and killing of bacteria. |
