Yes, the only control there is is being vaccinated. Yet all tourists are vaccinated. If locals were not vaccinated before the sandbox opened, that is a huge problem for them, but not the vaccinated tourists.
Flus/coronavirus symptoms can only be mitigated with a vaccine. But like all other flus, swine and avian, there will still be high numbers of deaths each year as will be the case with covid from now on.
You never fully eradicate a virus, only mitigate/lessen the symptoms with a vaccine