Did you read the article? Because that is not what it says. To help you, originally, the data indicated it was effective for 90 days. Now (htat they have more, longer term data - my assumption) they can say its effective for 180 days (six-months for you). We will see how htings progress over the next 90, 120 and 180 day periods.,In six months you can go back and get it again.