As you say, antibodies != protection necessarily. And asymptomatic people don't have antibodies from the start though they do after infection albeit without sym

As you say, antibodies != protection necessarily. And asymptomatic people don't have antibodies from the start though they do after infection albeit without symptoms. They do have T-cells which offer protection in these cases. But the status of one's immune system is critical so adopting advice in this department is paramount.