What’s behind this new wave? Schools started back during the first week in September, and while this may now be contributing to the new wave, infections started increasing too early for schools to be the primary driver.
One possibility could be people returning from overseas holidays. A recent ONS analysis found travelling abroad was one of the strongest risk factors for testing positive.
But probably the main driver behind this current wave is waning immunity. We know that for most highly transmissible endemic infections the incidence of infection is largely driven by the rate at which immunity is lost in the population.
We also know that protection against infection or reinfection following COVID vaccination or indeed an infection may not last long.