Can anyone explain me, why vaccinated people don't have to provide negative test results for covid, just as those unvaccinated have to do?
People who are fully vaccinated could be infected and could transmit the virus onward in the same way as unvaccinated, so why it's been commonly assumed that they're "safe" and don't need to be tested anymore?
The fact that the instramuscular vaccines (all covid vaccines currently in use are instramuscular) don't prevent from infections and further transmission of the virus had been known just from the beginning, long before the process of vaccination started.
Here's the article from Nature magazine, published in the September 2020. In short, among other things, it highlights the intramuscular vaccination doesn't give the immunity of upper respiratory tract (but "only" in the lower one) and because of that vaccinated people could still infect others.
The development of vaccines against SARS-CoV-2 is reviewed, including an overview of the development process, the different types of vaccine candidate, and data from animal studies as well as phase I and II clinical trials in humans.
www.nature.com
Fresh study from The Lancet Infectious Diseases:
Vaccination reduces the risk of delta variant infection and accelerates viral clearance. Nonetheless, fully vaccinated individuals with breakthrough infections have peak viral load similar to unvaccinated cases and can efficiently transmit infection in household settings, including to fully...
www.thelancet.com
"fully vaccinated individuals with breakthrough infections have peak viral load similar to unvaccinated cases and can efficiently transmit infection"