As we head into the third year of the global COVID-19 pandemic, everyone would just like it to be over.
The previous hope that the end was nigh in the early summer of 2021 has been replaced by the most vertical ascent in new cases yet, in the United States and many other countries. Driven by low vaccination rates globally, and mostly uncontrolled transmission of SARS-CoV-2, newer variants keep emerging.
Omicron is the latest Variant of Concern (VOC), designated so by the World Health Organization, which is now overwhelming healthcare systems in the U.S. and Europe.
First detected only on Nov. 9, 2021, omicron has surged globally due to its very high transmission rate and ability to escape previous immunity.
Omicron’s reproductive number (R0) is estimated to be as high as 10, second only to the extremely infectious measles, mumps, pertussis, and varicella. This compares to R0 of 2.5 for the original strain of SARS-CoV-2 and ~5 for delta. Because this number is an exponential coefficient, a “doubling” of R0 portends for an extreme jump in infectiousness.
