If [R0 value being approx. 5.7] true, this has several important implications, beginning with the concept of herd immunity. Herd immunity occurs when a sufficiently large percentage of a population becomes immune to a disease, either through infection or vaccination, with the result that transmission no longer occurs readily, thus protecting even those who are not immune. In the case of SARS-CoV-2, reports suggesting that herd immunity will be achieved when 55 percent of the population is immune assume that the R0 of the virus is 2.2. If the R0 is 5.7 instead, then 82 percent of the population must acquire immunity—because the higher the reproductive number, the larger the immune population must be to halt the spread of the disease. An R0 of 5.7 rather than 2.2 would require billions more doses of vaccine globally—or, if herd immunity is achieved only through infection, millions of excess deaths worldwide.
Another implication of a higher reproduction number is that seasonality—which, if applicable to SARS-CoV-2, is estimated (based on studies of other coronaviruses) to reduce transmission by about 20 percent during the summer—will not lower the R0 to a range anywhere near 1.