There are dozens of ways the attenuated strain could be spread. You could do anything from going door to door sticking an infected swab up people’s noses to one of your contagion parties (they would be fun).
Actually once a safe strain was identified it would be impossible to stop people spreading it on their own. People would test to make sure they had the safe strain and then invite everyone they knew around for tea and scones.
Everyone they knew would need screening for the asymptomatic deadly strain first, or there would be a risk of everyone at the party catching the wrong strain.
Actually once a safe strain was identified it would be impossible to stop people spreading it on their own. People would test to make sure they had the safe strain and then invite everyone they knew around for tea and scones.