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When the antiviral treatment Paxlovid came into wider use for Covid-19 infections earlier this year, doctors who prescribed it and patients who took it noticed that symptoms sometimes flared up again a few days after having gone away. Some people even tested negative before they experienced the rebound. But this puzzling phenomenon can occur whether you take Paxlovid or not, according to a new study. Researchers found that when patients received a placebo instead of treatment, a portion of them still experienced a rebound of their symptoms after they had initially improved. (Sheikh, 10/27)

Nearly one third of 158 untreated COVID-19 patients experienced symptom rebound after being symptom-free for at least 2 consecutive days, finds a study of US adults published yesterday in JAMA Network Open. (10/28)

For the first couple of years of the coronavirus pandemic, the crisis was marked by a succession of variants that pummeled us one at a time. The original virus rapidly gave way to D614G, before ceding the stage to Alpha, Delta, Omicron, and then Omicron’s many offshoots. But as our next COVID winter looms, it seems that SARS-CoV-2 may be swapping its lead-antagonist approach for an ensemble cast: Several subvariants are now vying for top billing. (Wu, 10/29)

Gone are the simple early COVID pandemic days of 2020—in terms of viral evolution, at least. The transfer of power used to be relatively straightforward from variant to variant, from the original strain, to Alpha, to Delta, to Omicron—one washing over the world before another took over. Now, it’s a battle royale between prominent viral “families” warring to keep power within the lineage. No single family—BA.5, XBB, nor BQ—has achieved global success this fall. Not yet, at least. (Prater, 10/29)

The WHO advisory group said XBB and BQ.1 don't currently diverge sufficiently from each other or from other Omicron lineages that have extra immune escape mutations to warrant a variant of concern designation or a new label. "The two sublineages remain part of Omicron, which continues to be a variant of concern," the group said. (Schnirring, 10/28)

China lashed out at a report about a lab in the city of Wuhan where the coronavirus first appeared, saying it was driven by politics in the US. (10/31)