What matters is not so much the numbers (you're not seeing new cases at the moment that people were infected - you're seeing people who got infected nearly a week ago, and not all at once); it's how much the government acknowledges the problem, how strongly they're responding to the problem, and how sound their isolation response is. In South Korea, the virus found a near-perfect host in terms of a cult, but R0 only applies for populations where no action is being taken and people go about their normal lives.
Iran is more concerning because for the most part people are going about their normal lives. When the situation is not properly acknowledged and proper measures not taken, the disease can continue its spread unhindered - every week, a new round of multiplications. I want to see convincing evidence that Iran is getting on top of this. I want to see the reported case rate in Iran spike, because the death rates and the outsiders-got-infected-inside-Iran rates suggest that there's a lot of latent cases that have not been detected - or at least, reported - yet. I want to see the public in infected areas at least wearing masks and being told to wash their hands, and workplaces taking control measures.
Outbreak centres can be controlled, but it takes acknowledgement and active measures to do so, and it's a slow process. The deeper a disease gets established, the more stringent the necessary measures and the longer it takes. Iran is only shooting itself in the foot here. All of its neighbors are going to end up closing their borders and airlines cutting of flights, and soon, if they don't step up.
