According to that study, within 90 days of taking the 2nd vax shot, the levels of protection fall to less than 70% against the Covid virus. With the way the chart was dropping in %, within 180 days (6-months), the level of protection would be down to roughly 50%.

By the end of this year, for most vaxxed Americans, the level of protection will fall to less than 35%, which is almost like having no vaccine at all. Within 1-year of having your shots, there will be no statistical difference in your ability to withstand the Covid virus vs. any unvaxxed person.

In that case, what good are vaccine passports? People who were fully vaccinated in March are down to 50% protection now... and dropping. People who had it in May are down to 70% protection and dropping. By Christmas, nearly every vaxxed person will have less than 40% protection vs. Covid. At that point, a vaccine passport would be meaningless. :>)

Of course, you could always line up to take the deadly "booster shot", but count on it being ineffective quickly as well.