A new, highly contagious Omicron subvariant, known as BA.2, is now spreading across the U.S., New York, and the Hudson Valley.

While the new Omicron subvariant sweeps parts of the world, Hudson Valley health leaders say they're keeping a close eye on cases that are now showing an upward trend.

Many across the Hudson Valley say they are done with COVID, but infectious disease experts warn COVID isn't done with us just yet - especially as BA.2 begins to make its rounds.

Infectious disease experts say this is a variant that's more transmissible and attacks the upper respiratory system, which means symptoms are milder and the vaccines available now are effective against it, according to doctors.

In large parts of the world, it's still driving another COVID surge.

Officials say previous trends show how that can be a precursor to what we see here.  

"Omicron that's happening overseas – usually we have about a three-week lead time before we start seeing the impact here in the states…we want to continually be optimistic but paying attention to that," says Westchester Deputy County Executive Ken Jenkins. 

That's why state and local leaders say their eyes are peeled on the rising infection rate, although they do not expect a steep spike. Upwards of 40% of New York COVID cases are currently made up of the BA.2 subvariant, according to the most recent state data.

"We don't expect to see a steep surge in cases in New York state. It has been rising over the past couple of months, but we have not seen the kind of rate of growth that we've seen in the UK and in Europe," says New York state Health Commissioner Dr. Mary Bassett.

Health officials attribute that, in part, to high vaccination rates . They say, so far, the vaccine has been effective in protecting people against the BA.2 subvariant. "We have the tools today to manage these infections. We have antiviral, we have monoclonal antibodies that work against this," says Dr. Harish Moorjani, infectious disease specialist at Northwell Health

Doctors say while BA.2 is highly contagious, the symptoms appear to be milder that the original COVID-19 virus: fever, headache and body aches that typically last a few days. "This variant, BA.2, has an enhanced ability to attach to the upper airways, but much less ability to attach to lower airways of the lungs," says Moorjani.

Doctors say that's important because they tend to see less cases of pneumonia with an upper respiratory infection. So far, hospitalization rates are much lower with the BA.2 strain.

Health officials say those who start to feel symptoms should get tested immediately because that is one of the best weapons to stop BA.2 from spreading.