An explosion of infection rates among the non vaccinated.Sure there's a difference. The alpha variant had an r0 of around 2.5, Delta has an r0 of between 6 and 8. It is orders of magnitude more infectious than the alpha variant. The difference between now and march is that now we're sitting at the foothill of cases that indicate a coming tidal wave of explosive exponential infection rates and we know it.
They are gonna catch it at some point anyways.