Louise Wallace told a meeting of North Yorkshire's Outbreak Management Advisory Board on Monday that the latest figures showed a "much better picture" with a 43% drop in the county's weekly infection rate which now stands at 1,048 cases per 100,000 people.
However, she said infections were still higher than previous months and that this was putting pressure on care homes, hospitals and schools.
Ms Wallace said: "We are now seeing a decline in some of the numbers and I'm really hopeful that they are heading in the right direction.
"I'm cautiously optimistic that we are turning the tide, but we still do have 854 daily cases.
"And of course we have had changes to testing arrangements over the last few weeks which may be having an impact on some of the data."
Latest figures show there have been seven Covid-related deaths in North Yorkshire in the last week - fewer than this time last year when the county was averaging five deaths each day.
NHS staff told Monday's meeting that despite this improving picture, many patients were still being hospitalised with the virus.
They also expressed concerns that fewer people are now testing for Covid and that this was "skewering" the true rates of infections and estimates on how many more patients could need hospital treatment.
This comes as the self-isolation period for people who test positive has been cut to five full days in England.
People are now able to leave isolation after negative lateral flow tests on days five and six in a move to ease pressure on staffing shortages across the private and public sectors.
This was announced last week by the government which is reportedly seeing “encouraging” signs that the Plan B restrictions in England could be removed after a review on 26 January.
The current restrictions include guidance to work from home, the widespread use of face coverings and NHS Covid passes for some events.
Meanwhile, teenagers aged 16 and 17 can now book their booster vaccines online. The top-up jabs are also being made available to clinically vulnerable 12 to 15 year olds.
By Jacob Webster, Local Democracy Reporter