Worldwide there have been over 760 million confirmed coronavirus disease 2019 (COVID-19) cases, and over 13
billion COVID-19 vaccine doses have been administered as of April 2023, according to the World Health Organization.
An infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can lead to an acute
disease, i.e. COVID-19, but also to a post-acute COVID-19 syndrome (PACS, “long COVID”). Currently, the side
effects of COVID-19 vaccines are increasingly being noted and studied. Here, we summarise the currently
available indications and discuss our conclusions that (i) these side effects have specific similarities and differences
to acute COVID-19 and PACS, that (ii) a new term should be used to refer to these side effects (post-COVID-
19 vaccination syndrome, PCVS, colloquially “post-COVIDvac-syndrome”), and that (iii) there is a need to
distinguish between acute COVID-19 vaccination syndrome (ACVS) and post-acute COVID-19 vaccination syndrome
(PACVS) – in analogy to acute COVID-19 and PACS (“long COVID”). Moreover, we address mixed forms of
disease caused by natural SARS-CoV-2 infection and COVID-19 vaccination. We explain why it is important for
medical diagnosis, care and research to use the new terms (PCVS, ACVS and PACVS) in order to avoid confusion
and misinterpretation of the underlying causes of disease and to enable optimal medical therapy. We do not
recommend to use the term “Post-Vac-Syndrome” as it is imprecise. The article also serves to address the current
problem of “medical gaslighting” in relation to PACS and PCVS by raising awareness among the medical professionals
and supplying appropriate terminology for disease.