Why Covid-19 is spreading in the U.S. and Overseas

This summer in the United States, Covid-19 rates are reportedly particularly high in Arizona, California, Hawaii and Nevada. In these western states, the number of positive tests reached 15.6% on the week ending July 6th, 1% up on the previous week. The CDC’s investigations show that viral rates in wastewater are also on the rise once again.

A similar trend has played out on the other side of the Atlantic, where according to the UK's Health Security Agency, positive Covid-19 tests rose from 4% at the end of March to 14% by the end of June.

The recent rise has been attributed to the FLiRT subvariants, the latest evolution of the Omicron strain of Covid-19 which emerged towards the end of 2021. ...