They then go home or back to their community and spread it. As Matt Hancock said today you need to stop the younger people getting it to protect the vulnerable.
*17m tests not people tested, just because you are negative today doesn't mean you will be next week.
Agreed and this is where culture kicks in - in Thailand social distancing is strictly observed, when families or friends meet with elderly people there is zero social contact, masks are worn 100% of the time during social interaction - now I'm sure there are other reasons why Thailand has almost zero Covid but the fact that there have been no mass gatherings, no Covid parties, no infected sent to care homes, and that at all times the incredibly strict quarantine measures have been impeccably observed by the entire population is certainly part of the reason.
In the West the ignorance, arrogance and selfishness of so many who deliberately ignore even the basic guidelines - I'm afraid you can't fix stupid.
Sweden may well have had the right idea - if the population is going to ignore us we might as well just get it over with - still not sure they were right or wrong but it would seem the longer Covid drags on elsewhere the more 'right' they appear to have been.