Why does this alleged “vaccine” not stop transmission of the virus?

Crazy news reports are all over the place:

This is how the mRNA vaccine works: WHY PEOPLE WILL START DYING A FEW MONTHS AFTER THE FIRST MRNA VACCINATION – PROF DOLORES CAHILL

Australia’s initial vaccine rollout unlikely to stop Covid transmission, study finds

even a vaccine that is 90% effective at reducing disease will take time to manufacture, distribute and administer, and may have limited impact on SARS-CoV-2 [Covid-19] transmission and spread, or protection may be short-lived,” the review says. the vaccines lessen or prevent the vaccinated person from developing disease, but not whether they stop the vaccinated person from transmitting the virus to others.

Can you spread Covid-19 if you get the vaccine?

Elderly Britons who flout Covid rules after getting both doses of coronavirus vaccine could ‘more than offset’ the benefits, experts warn

Oxford-AstraZeneca COVID-19 vaccine ‘is not good enough’

UK Nurse Tests Positive for CCP Virus After Second Dose of Pfizer Vaccine Canceled