SPECIAL REPORT
The highly-transmissible Delta variant has complicated the quest to reach herd immunity because it can cause more infections in the fully vaccinated compared to Alpha or the original Wuhan strain, and has a much higher natural R number FROM the beginning of the pandemic, herd immunity has been touted as a sort of finish line or Holy Grail at which point the virus runs out steam and true normality returns. Fringe scientists and lockdown sceptics pushed for natural infections to be allowed to sweep through the healthy, younger population while the vulnerable and elderly were shielded. The mainstream view was that the threshold could be reached much more safely and reliably with vaccines, but - while they remain our strongest weapon - the explosive rise of the Delta variant has changed the arithmetic.