CDC data warns Omicron is rapidly spreading in US

New data from the Centers for Disease Control and Prevention (CDC) indicate the Omicron variant is rapidly increasing in prevalence in the United States, accounting for nearly three percent of all cases sequenced in the country over the past week.

As scientists race to understand exactly what impact the recently emerged Omicron variant of SARS-CoV-2 has on disease severity and vaccine protection, case numbers continue to rapidly rise in many countries around the world. A new weekly update from the CDC tracking the proportions of different variants in the US is reporting extraordinary growth of Omicron.

The new data shows Omicron accounting for 2.9 percent of all sequenced cases in the US. This is up from 0.4 percent of sequenced cases just one week prior. The variant was found to be particularly prominent in New York and New Jersey, accounting for around 13 percent of sequenced cases.

A recent CDC briefing with public health officials around the country warned of a potential January surge in cases. Speaking to CNN about this CDC briefing Lori Tremmel Freeman, from the National Association of County and City Health Officials, said the biggest concern was a looming triple threat from Omicron alongside rising Delta variant cases and a resurgence in influenza.

"It's the combination. It's kind of the perfect storm of public health impacts here with Delta already impacting many areas of the country and jurisdictions," said Freeman. "We don't want to overwhelm systems more, but it looks like that we need to prepare for that because if this virus spreads that rapidly, even though it doesn't make people that sick, they're going to seek testing."

CDC Director Rochelle Walensky also tweeted new data on the effectiveness of third vaccine doses. The data, tracking weekly case loads in nursing homes, reveals increasing breakthrough infections in two-dose vaccinated people. However, a third COVID-19 vaccine dose led to 10 times fewer positive cases.

This nursing home data of course mostly covers a period of time prior to the Omicron variant appearing. But recent emerging evidence from Pfizer and other researchers does indicate a third vaccine dose should restore a great deal of protection against infection lost in the face of Omicron’s ability to break through two vaccine doses.

While it is increasingly evident the Omicron variant is more transmissible compared to prior variants it still is unclear whether it generates severe disease. A lot of eyes are currently on the UK as it is experiencing one of the heaviest Omicron waves the world has yet seen.

As caseloads in the UK hit record highs, the National Heath Service is preparing for a subsequent wave of hospitalizations, which generally lag a couple of weeks behind new cases. Jenny Harries, head of the UK Health Security Agency, has called the growth rate of Omicron “staggering” and warned of a potential surge in hospitalizations over the coming weeks.

In the US many hospitals are already at critical points with Delta variant cases. An unprecedented message from the Mayo Clinic indicates its hospitals are currently full and overwhelmed with COVID-19 cases, and this is before the influence of Omicron has been felt.

“Now, an ominous question looms: will you be able to get care from your local community hospital without delay?” the message asks. “Today, that’s uncertain. Your access to health care is being seriously threatened by COVID-19. We need to stop the spread!”