If old myths could dance and slide down poles, the myth to "ONLY EAT OYSTERS IN MONTHS WITH THE LETTER 'R'" would be a stripper!
No, the earth is not flat. That's been made pretty clear from the modern age of astronomy.
No, George Washington did not chop down a cherry tree. He only cut OAK firewood.
And no, Jesus was not born on December 25th. We only celebrate his birth on that day.
Like a lot of myths, the myth that you cannot eat oysters in certain months of the year because your great g-ma said so almost like the one about George Washington and the cherry tree.
How many times have I heard "My grandma told me to only eat oysters in months with the letter "R""? I've lost track. It has been at least hundreds - maybe thousands.
The polite response is to find an appropriate way to remind the person making the statement that it was a TRUE statement before the advent of mechanical refrigeration in the 20th Century. I also try to work in other factoids like the shellfish industry being highly, HIGHLY regulated by state and federal bureaucracies and laws. I also remind the person with whom I am conversing that the shellfish industry is SAFE for everyone who has a normal immune system. But, let's face it, if you have any reason NOT to eat raw eggs or raw oysters, DON'T! Eat something else.
It might surprise people to know that shellfish harvested in the cooler waters of New England are more prone to creating outbreaks of the vibrio infection than are shellfish harvested from warmer climates. The statistic don't lie. But the MYTH that cold water oysters are safer than oysters from other parts of the country is yet one more myth that is gyrating on the stripper pole.
If you want to be careful about anything related to oysters, it would be to know your source and never eat oysters that have no pedigree. Every legal bag or box of oysters has tag that says where they came from. That tag is there to show you and the industry regulators all of the information necessary to track backwards to know if the oysters have the proper credentials to make them safe.
Me? I don't go to strip clubs - never have and never will. But I've eaten my share of Florida oysters. They're safe. Eat local. Save the planet.