Has Delta variant reached its peak? Wisconsin doctors say not yet

MADISON, Wis. (CBS 58) -- Some national data shows cases of the Delta variant may be trending downward in certain states, leading to questions about whether it's reached its peak. But local doctors say not so fast.

National health organizations are keeping a close watch on these variants.

Dr. David Letzer, chairman of the Wisconsin Medical Society Task Force on COVID-19, said variants of COVID-19 are to be expected, but with vaccines, they could have been stopped in their tracks.

"The more people that get the virus, the more the virus replicates, the more risk for mutation," Letzer said. "That's really what's disconcerting for us health care workers is a lot of what we're dealing with is really preventable."

The CDC has listed four strains as "variants of concern" here in the US, including the highly contagious Delta variant. 

Wisconsin doctors said this has been a regional virus all along, and even if Delta peaks in other states, they're not comfortable saying that it has peaked here yet. In Wisconsin, cases, hospitalizations and deaths continue to increase.

"The only way to know that you have reached the peak is when it starts to come down and so far we're not seeing that. So how far away we are from the peak -- it's hard to say, but certainly the trajectory is upward at this point," said Dr. Nasia Safdar, medical director for infection prevention at UW Health.

Last week, the World Health Organization added another strain known as Mu as a "variant of interest."

Letzer said there are concerns the vaccine success rate may be lower among cases of the Mu variant.

"It's important for us to keep track of the strains to see: Are there concerns that the vaccines won't work? Will there be reasons to change the vaccine? Will some of our therapies no longer be effective?" he said.

Mu was first discovered in Colombia, which Letzer said is a reminder that this is a global pandemic. He said even if people feel good about the vaccine rates where they live, the pandemic has to be addressed on an international scale because otherwise people will be at risk when they travel internationally.

Doctors said there is a lot of circulating virus, and as COVID-19 continues to find people who are unvaccinated, doctors are also seeing more breakthrough cases.

"There will undoubtedly be future, additional variants and to what extent they play a role in how this pandemic unfolds -- we just have to take it one variant at a time," Safdar said.