Manuscript/Research article: A formal research article that is submitted to the editor of a journal for publication, peer-review and/or to a preprint repository. It reports the results of original research and assesses its contribution to the body of knowledge in a given area. See "Format of Research Articles" below. In the sciences, this is considered a primary source article.
Review article: An article that synthesizes and evaluates information from several primary articles. It does not describe original research conducted by the author(s). Instead, it gives an overview of a specific subject by examining previously published studies on the topic. By interpreting the findings of previous studies, review articles are able to present the current knowledge and understanding of a specific topic.
Preprint: An article that has not yet been peer-reviewed. Repositories like arXiv, bioRxiv and medRxiv house pre-print articles to allow for immediate access to research. It is the responsibility of the user of such preprints to vet the information in them and to regularly monitor the preprint repository to follow the status of the preprint.
Case Report: Typically used in medical related fields. It is a detailed report of the diagnosis, treatment, response to treatment, and follow-up after treatment of an individual patient or up to several patients. It is used to describe a rare or unique condition or unexpected associations or findings.
Popular media or website: Online resources where individuals share their personal opinions and interpretations (not peer-reviewed). It is the responsibility of the researcher to verify content before sharing it any further.
Infodemic: Not a real type of article but a term used to illustrate the rapid spread of information/misinformation/disinformation. COVID19 Infodemics Observatory interactive map