This is one thing I don't agree with corbett on, he brushed it off because he claimed they didn't get some other predictions correct and therefore this should be discounted. From what I've seen they've addressed it at least once or twice and stuck by their decision, granted their reason is people will be moving en masse from these countries to other areas, but I don't think the math actually supports that. Coincidentally, the countries with the largest drops in population have higher rates of boosters.