I guess the CDC updated their page.
https://www.cdc.gov/ncird/whats-new/covid-19-can-surge-throughout-the-year.html
Many respiratory virus illnesses peak during the winter due to environmental conditions and human behaviors. COVID-19 has peaks in the winter and also at other times of the year, including the summer, driven by new variants and decreasing immunity from previous infections and vaccinations. You can protect yourself from serious illness by staying up to date with vaccinations, getting treated if you have medical conditions that make you more likely to get very sick from COVID-19, and using other strategies outlined in CDC's respiratory virus guidance.
I have a friend in a nursing home, and I don't know how it's going for other illnesses, but for the past two years they have been getting 3-4 covid outbreaks a year, and it seems to take out a few residents each time. Better than the start, were it was taking out dozens, I guess, but they clearly need to implement some kind of plan to prevent the spread of airborne illnesses year round. I still can't believe the government okayed going back to normal in hospitals and places serving the medically vulnerable.
HVAC is a big one, putting in HEPA filtration but also turning over air. Might as well maintain/improve AC while it's being done I guess - but all that costs money and so many nursing homes are for-profit so they'd rather not spend money on capital improvements when it can go to ownership. Otherwise, they could be stricter with PPE and not letting people in with symptoms but there's just so much fucked up shit that's happening to make workers feel okay or even needing to come in when they're sick.