We start 2023 with a seeming pandemic lull. Moving through the trio of viruses comprising the tripledemic, respiratory syncytial virus (RSV) hospitalizations have plummeted, COVID-19 hospitalizations are dropping, and the influenza epidemic curve is not rising. For the five-county Denver metro area, the most recent RSV hospitalization count (64 for the week of December 24) was 20% of the peak in mid-November. For COVID-19, Colorado hospitalizations dropped from the November peak of 440 to 306 last week.
case numbers are also in decline as is test positivity. The rate of influenza hospitalizations has been stable for the last three weeks. The scary proposition of the tripledemic did not materialize, but the unexpectedly high peak for RSV in relationship to past years did strain pediatric capacity. With the holidays ending, we might see a resurgence of infections with respiratory viruses, reflecting holiday get-togethers and travel. Watching the news, the snaking lines of abandoned Southwest Airlines passengers screamed “superspreader event.”
We have seen COVID-19 lulls before, inevitably reversed by the arrival of the next, more transmissible variant. At the moment, the XBB.1.5 subvariant has become dominant in the United States, displacing BQ.1 and BQ.1.1. A just-published paper in Cell provides disturbing news about the most recent variants—the BQ and XBB subvariants. The former branched from B5 while the latter resulted from recombination between two BA.2 lineages. The bad news in the article: in vitro tests show high resistance of these subvariants to neutralizing antibodies and resistance to available antibodies. So far, this bad news is balanced by what is happening in the United States and in Colorado—even with the rise of these subvariants, the nationwide epidemic curve is not turning upward and is declining in Colorado.
My disclosable holiday reading included the recently published book Breathless: The Scientific Race to Defeat a Deadly Virus by David Quammen. I had previously praised Spillover, his 2012 book that presciently predicted that the next emergent virus to spillover to humans might be a coronavirus. SARS-CoV-2 is the topic of Breathless. Quammen begins with the story of its emergence and proceeds to trace its passage around the world and the ever-changing threat that it posed as it endlessly mutated. He nicely covers the insights gained by tracking the molecular epidemiology of the virus. The book is replete with accounts of the researchers involved and replays the full alphabet mélange of variants over the last three years.
The last one-third of the book explores the origins of SARS-CoV-2 and the evidence supporting the competing hypotheses of emergence from the Wuhan Institute of Virology (the lab-leak hypothesis) or from one or more spillover events (natural origin hypothesis). Quammen covers the various expert groups, publications, and opinions comprehensively. Of course, at this point we know the answer—there is still no certain answer. The bottom line on the lab-leak hypothesis and the underlying scenario of an infected laboratory worker: “It’s not impossible. But it seems unlikely.”
I finished Breathless across the New Year’s holiday—its dates marking portentous anniversaries of the first reports of COVID-19 from China. I learned much from the book about the application of the powerful methods of molecular evolutionary virology and had a refresher on the parade of variants and subvariants over the last three years. Starting the last chapter, Quammen writes: “This is a book about the science of SARS-CoV-2.” Those looking for an inciteful look-back at the non-science aspects of the pandemic will be disappointed.
I was hoping for more in-depth probing of the collision of science and everything else that set the pandemic in motion and sustained it. For me, the book read as a rerun of a story that I already know. If you have not been following the story closely, this is a good book about using modern science to tackle a virus that has caused a pandemic. I await the still unwritten analogue to Barry’s The Great Influenza.
Happy New Year. I hope for a quiescent pandemic making its way to calm endemicity. There is much else to hope for to benefit public health. My list is lengthy with many obvious items, but an end to the many conflicts underway is at the top.