#CovidWinter may be extraordinarily bad
I linked The National Respiratory and Enteric Virus Surveillance System (NREVSS) National Trends a few days back. This shows the past two years' history of four non-COVID-19 coronaviruses in the United States. These start to appear in testing around mid-October, peak from late December to April, and fade by late-May to June. Again, though these are NOT Covid, the common trend and other data for COVID-19 strongly suggest winter as the disease's most prolific season.
This also suggests that the January-April emergence of COVID-19 actually occurred about halfway through the peak season, attenuating spread compared to a full-length outbreak.
More evidence comes when looking at South American and African data. For much of the period June through September, South America performed conspicuously poorly for COVID spread. This increasingly looks like a wintertime peak.
Africa as a whole has been relatively spared Covid, and hasn't shown a strong seasonal trend. Data are also more questionable thad for most other regions. But Africa slso spans both Northern and Southern hemispheres, and the region that has seen the largest outbreak, Southern Africa geneerally, and South Africa specifically, also seems to show a winter peak. Cases are now trending high in Morocco, in Northern Africa.
The other southern region, Oceania, has fared well, though again Australia's peak spans winter.
European cases began rising notably in September. @Joerg Fliege, teaching at university in the UK has been posting regular updates and as of mid-September was showing cases doubling every few days --- relatively low numbers at firsst, but it's the growth rate that matters. More broadly, cases didn't start rising noticeably until September--Occtober. This was about 4--8 weeks ahead of the US rise, and in both cases more northerly regions seem first affected.
If this is accurate, then we may well be on the cusp of an extraordinarily bad Covid Winter, with infection peaks occurring in February--March.
Interventions, including lockdowns, masks, and vaccines (available likely March--June) should help, but this looks like it's going to be quite bad, with peak infection and death rates 4-8 times levels being seen possible.
The good news is that European case growth has slowed, flattened, or declined innmany countries, for now. Quarantine does in fact wwork. But there's six months between now and June.