Friday, September 01, 2023

CDC Nowcast & BA.2.86 Update


While the Internet appears to be transfixed by rampant speculation over the future impact of BA.2.86, it still doesn't show up - even as a blip - on the CDC's bi-weekly Nowcast.  

Instead, based on limited surveillance and testing (only 4 of 10 regions submitted enough data for regional analysis), EG.5 (21.5%) and FL.1.5.1 (14.5%) lead a very deep stack of roughly 30 variants currently being tracked by the CDC.

While currently in 6th place, HV.1 has shown impressive growth, doubling (from 2.5% to 5.1%) over the past 2 weeks, while most of the other variants on the list have lost ground.  Despite the hype over BA.2.86, it is EG.5, FL.1.5.1, and a short list of other XBB variants that are probably responsible for the recent increase in cases. 

Although there are a lot of strong (and conflicting) opinions online about the future course and impact of BA.2.86, there is still far too much we still don't know about this variant.  

We know is antigenically distant from other variants we've seen, and that raises concerns over how much protection existing immunity will provide against infection. But its infectivity, relative severity, and its biological fitness and ability to compete with other variants - are all unknowns.

BA.2.86 may become the next big phase of COVID in the months ahead, or it could fizzle. 
In 2021 both the Beta and Gamma variants caused regional outbreaks in South Africa and South America, but were unable to compete on the global stage against Alpha and Delta, and then Omicron.  

This new lineage continues to evolve, and additional mutations could either enhance or degrade its performance going forward. That said, it has rightfully captured the attention of health agencies around the globe.

While we wait for better answers, the CDC has updated their Initial Risk Assessment On COVID BA.2.86 (released Aug 23rd). Due to its length, I've only included the opening sections. 

Follow the link to read the full report:

Update on SARS CoV-2 Variant BA.2.86

August 30, 2023, 3:30 PM EDT

CDC is posting updates on respiratory viruses every week; for the latest information, please visit CDC Respiratory Virus Updates.

CDC is tracking a new SARS-CoV-2 variant called BA.2.86 and working to better understand its potential impact on public health. This update follows CDC’s initial risk assessment summary on August 23, 2023.

The updated COVID-19 vaccine will be available in mid-September. Learn ways to keep you and your loved ones safe as we head into the fall season.

What’s New?

CDC continues to track the presence of the BA.2.86 variant.

Since CDC’s initial risk assessment, this variant has been identified in additional countries from both human and wastewater specimens.

The variant has been identified in at least four states in the United States in samples from either people or wastewater.

This variant is currently being studied in the laboratory to help understand how the immune system may interact with this virus.

The current increases in cases and hospitalizations in the United States are likely being driven by infections with XBB lineage viruses, not the new BA.2.86 variant.


Viruses, including the virus that causes COVID-19 (SARS-CoV-2), change over time. SARS-CoV-2 viruses with significant genetic changes are called “variants.” A new variant that is very different than previous variants could behave differently, with potential changes in contagiousness or how well it responds to treatment. Over the last few weeks, a new variant called BA.2.86 has been detected in a small number of samples from infected people and waste (sewer) water in several countries, including the United States. This variant is notable because it has multiple genetic differences compared to previous versions of SARS-CoV-2 and it has been detected in several locations within a short amount of time.

Current Risk Assessment

Based on current information, existing tests used to detect and medications used to treat COVID-19 continue to be effective with this variant. Scientists are evaluating how previous immunity from vaccinations or past infections protect against this new variant. Tests of how well antibodies block the virus from infecting cells give us one measure of how well one part of the immune system might handle BA.2.86. Along with antibodies, other parts of the immune system have important roles in protecting people from the most severe outcomes of COVID-19. These other parts of the immune system have been less affected by viral evolution and are not predicted to have decreased activity against BA.2.86.

CDC’s current assessment is that the updated COVID-19 vaccine, which will be available in mid-September, will likely be effective at reducing severe disease and hospitalization. Immune responses generated from prior infection also help protect against severe outcomes of COVID-19. There is currently no evidence that this variant is causing more severe illness. That assessment may change as additional scientific data are developed. CDC remains committed to releasing updates on trends and observations of this variant.

Prevention Actions

If licensed/authorized by the FDA and recommended by the CDC, updated vaccines will be available as early as mid-September at your local pharmacy or doctor’s office.

What can you do to protect yourself and others as we learn more?

At this time, we don’t know how well this variant spreads, but we know that it spreads in the same way as other variants. That means you can still take the following actions to protect yourself and others from infection:
  • Get your COVID-19 vaccines, as recommended
  • Stay home if you are sick
  • Get tested for COVID-19 if you are sick
  • Seek treatment if you have COVID-19 and are at high risk of getting very sick
  • If you choose to wear a mask, wear a high-quality one that fits well over your nose and mouth
  • Improve ventilation
  • Wash your hands
         (Continue . . . )