How to Handle the Winter Surge?
In the past 4 months, Delta has remained dominant (see covariants.org) regardless of “new variants” that have peppered the news. Nothing else can get a toehold. Even the riff on Delta, AY.4.2 is only moderately more transmissive. Delta might be as contagious as it gets. So why are we starting to see new climbs in Europe and some states.
What has changed is people are getting more “back to normal.” Highway traffic last evening in the SF Bay Area was about what I would expect on a Saturday. A shopping center lot I visited was pretty dang full. People are out there again…and cases are climbing in the Bay Area as a result, though since we are starting from a reasonably low place, no one has really noticed much.
I have also been watching to see if there would be a cold weather surge in the US, similar to what began in late September 2020, with the upper midwest being the early adopter canaries in the coal mine. It didn’t happen this year, but it was also substantially warmer in places like Wisconsin than it was last September/October.
Cold weather is credited with more folks crowding indoors thus increasing transmission. There is another factor when we breathe cold air. The wild type virus reproduces in human respiratory lining tissue at much higher rate with a few degrees difference in temperature. In winter when we breathe cold air, the lining drops a few degrees. The subsequent explosion in viral titer during an infection will make people both sicker and more contagious as each exhalation releases more virions into the air. It is unknown if crowding or faster viral replication dominates the cold weather effect. No doubt both play a role.
Finally, towards the end of October, temperatures began falling and sure enough, cases have begun ticking upwards in some northern areas. I suspect we will see a lot of alarmingly toned stories in the news in the coming weeks. Meanwhile, things are getting hairy in Europe (see figure at the top). Is the US doomed to as grave as November-January 2020? Not necessarily, and my personal opinion is no.
A Little Different This Time
Take a look at the slopes of various surges in this log plot of some of the states starting to see cases climb.* The slopes are not as steep as the US summer delta surge nor even the wild type surge in Fall 2020 (the more contagious Alpha was not prevalent in the US until the spring), though Wisconsin is looking a little like that slope. So what is different? What is driving this surge and why is it not as bad?
My opinion is behaviors are driving this new climb. People are gathering and living a lot more. Folks are interacting a LOT more than they were a year ago AND we have this far more transmissible variant (Delta), yet cases are not climbing as quickly. The climb is is ameliorated by vaccination rates, and lower susceptibility in the populatoin due to prior exposure. Instead of being off the rails rapid had we behaved like this a year ago we get what we see now. The only reason we are noticing the climb is because we are starting from a higher point. We are driven more by absolute numbers instead of trends.
What this winter might look like
There is still danger. Hospitals can still fill up and are already in some places: Colorado is taking an emergency posture due to the scarcity of beds. When this happens, public health overall suffers. People delay treatment and when a treatable illness gets to the point it can no longer be ignored a patient might be out of luck and will die from something they would not have in other times. These are non COVID deaths that are still an effect of the pandemic.
Case growth is much more easily managed with behavior changes when the slope is shallower. When it is steep, by the time governments react and people start to change what they are doing, more climb is baked in. When it is shallow, the curve does not travel as far by the time people respond. It will be easier to avoid dramatic peaks, but people still need to be willing to be disappointed sometimes when some planned activity is no longer a Good Idea.
I believe people willbe living their lives, getting more back to normal and local hospitals will more slowly fill. In the past once the news became scary, people backed down. This time, those few weeks that transition takes means a less critical situation by the time behavior changes make a difference. The one wild card is folks are so tired of curtailing their lives maybe it will be harder and slower to reverse course once it becomes important.
The Post Pandemic World
In the longer run, hybrid immunity or other factors will be how this ends. Maybe it turns out well for us all in another year as we all get exposed at some low level and our bodies get trained (see links in this sentence). Or it could be older folks will need vaccine boosts for the rest of their lives and it is the children growing up now with SARS-CoV-2 floating around who can ignore it, possibly needing a short course of vaccinations and boosters when they are small to dull the odds of their first case being nasty, like we do today with rotavirus .
I am convinced the Pandemic ends gradually with us taking two steps forward to normalcy and one step back as needed, until life looks like it did in early 2020. The unknowns are how long that will take, and how many die on our way. This latter is something we can control if we row together when it becomes necessary.
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*I use log plots because that slope is proportional to the rate of transmission. This is, in my opinion, the best gauge of how fast it is spreading and whether we are headed for big trouble. Last fall, using this indicator it was clear to me by early November we were heading for trouble. I began posting about it mid month. Meanwhile, everyone was excited about how low cases were still in abosolute terms and not noting the rising the storm.