It is unfortunate that people often use the word “study” in describing COVID-19. Unfortunately, the use of the word “study” is a marketing catchphrase to attract people’s attention and legitimize the views expressed.
In reality, concerning COVID-19, no study has been done or can be done. Conducting an investigation/study requires an actual or physical sample of the substance and a valid test with a measurable parameter. In the case of COVID-19, none is available, including a test, the virus (SARS-COV-2), RNA and/or protein.
Even in the case of masks’ usefulness or relevance, all studies/claims have to be fake or false, as testing a mask’s efficacy requires a physical sample of the virus that does not exist [link]. Hence, all “studies” or claims in this regard will remain unsubstantiated opinions – thus requiring frequent flip-flopping.
In addition, people do not realize that opinions/stories of virus mutation are examples of the flip-flop to hide the lack of vaccine relevance or efficacy, as vaccines have never been tested against the virus [link]. It is a scientific fact and not an opinion.
Just be careful when reading the literature or listening to “scientific” or “expert” opinions.