I have always maintained that the double / single dose, DOES NOT give you immunity it just protects you from serious complications
I.E. double dose and you have a sniffle and a headache, single dose and you have the headache and hayfever type / heavy cold, no dose and you are more than likely to have either any of the previous or hospitalized and the chance of death, that saying even these could happen in rare cases to those with the highest dose level.
Being vaccinated is not a guarantee of immunity, you can still catch it and still transmit it that is where everyone is failing to understand - the jab is not a silver bullet