Apart from the SA variant, we're currently more of a threat to other countries than they are to us because of our homegrown highly transmissible version.
The good news is that a peer-reviewed study among NHS staff in Newcastle has shown that those who were infected in the first wave do not catch it again. Those who report the symptoms don't actually have Covid19.
And a survey among those without symptoms didn't find that any of these 'first wave' staff were carrying the virus at all. People have good immunity for at least 6 months.