There is no evidence (as yet) that "herd immunity" is even such a thing for Covid - nor that the Biotec vaccine prevents virus transmission.
Virus protection might not even last long either & could require a booster every year- we simply do not know.
The new Singapore-Hong Kong air bubble is probably the first of many between low infected Asian countries. I cannot see Europeans being allowed anytime soon into Asian countries.
Vaccines are the only answer we have for now, & I'd be pretty sure China is working flat out on this.
Side effects of any of the vaccines are yet to be disclosed.
BTW- break Covid restrictions in Hong Kong will result in £2.5K fine AND 6 months in prison- court appearances are swift. As always in Asia compliance is extremely high. The weakness of European countries-particularly the UK, is poor compliance & enforcement of regulations.
https://www.scmp.com/week-asia/healt...ll-coronavirus