What history tells us about the delta variant — and the variants that will follow

First, even if the virus does escape vaccine protection, it will happen very gradually — and does not necessarily mean disaster. We should have time to adjust vaccines, and so far, Moderna, Pfizer, Johnson & Johnson and Novavax (which will likely get emergency authorization from the Food and Drug Administration soon) all protect against all known variants. But even if their efficacy declines significantly, they will still save huge numbers of lives. Influenza vaccines are routinely only 30 to 50 percent effective in preventing illness but still exceed 80 percent efficacy in preventing ICU admission.