We really don’t know when the end of the season occur. Some coronaviruses are seasonal and others are not. It depends on their UV Susceptibility. We have wound UV exposure devices to China to cleanse we’re sanitize rooms, they appear effective. This is promising, but we won’t know until the season changes.
Seasonality is also behavioral--in the winter we tend to spend more time indoors and in closer proximity in the Northern Hemisphere, which increases likelihood of aerosol/fomite transmission of viruses. Brazil, in the Southern Hemisphere, is experiencing another thrashing; their influenza season is also inverse to ours in terms of incidence vs season. Relative humidity changes might provide a better environment for viral survival in different seasons. Vitamin D deficiency due to reduces sunlight exposure is thought to play a potential role in increasing susceptibility to numerous pathogens....
As with influenza, colds (many types of viruses, including coronaviruses) and Sars-CoV-2, seasonal cyclicity is probably multifactorial. Covid hasn't been around long enough to pin it down precisely, and its closely-related predecessor, Sars-1, didn't spread far enough to provide enough data for useful analysis.
Not incidentally, we've had very low influenza reports for 2020, but last year was also a bell-ringer in terms of it being the year-to-date with the maximal number of flu vaccines ever administered in the US.
Also not incidental is the fact that the CDC-recommended indoor 6-foot distancing was decided as a compromise: Several valid studies showed that 12-15 foot distancing (indoors) is multiple times more effective than the 6-foot "guidelines", but weren't announced because they simply wouldn't have been accepted by the public. So they moved the goalposts--regression to the mean. With vaccines out now, they're reconsidering to drop to this even to 3 feet, which is absurd (but great for schools/restaurants opening). This is because people have pandemic apathy and already aren't (haven't been) following guidelines, and wouldn't now. This is understandable given the conflicting information that's been provided from the start, and even now.
The USA is not, unfortunately, a science-focused nation. Combined with the contradicting information we've received from those in charge of the CDC and NIH, and the political pressures behind some of those proclamations, I, as an ardent "Vaxxer" with a PhD from a decent US med school and decades of hands-on medical research, can fully understand peoples' "Anti-Vax" skepticism. And it disgusts me that it's become a political tool.
If you've already had Covid or are fully vaccinated, you
probably are able to be an asymptomatic carrier/spreader. Akin to a person with herpes-2 who is a "latent shedder", that can transmit disease even if they haven't had an overt outbreak in years. Or the common cold carrier who only has sniffles for a day or two but then it "goes away" instead of having 10 days of misery. You might be less infectious, you might be less ill, but you're still a (hobbled) virus factory (and spreader), even if you're not blowing green snots on your pals... Meaning, even if you're vaccinated/recovered/protected (for now), still please practice safe hygiene in your interactions with others. It's just polite. And might save a life.