Currently-available early-indicator data reinforces last week’s observation that the months-long decline in new COVID infections here in Ontario and across Canada has bottomed out and is again beginning to rise. 

The most reliable of the currently-available early indicators of COVID infection rates is PCR testing rates for the viral load in municipal wastewater. As you can see from the composite chart from the week just passed, Ontario’s wastewater test results have continued sloping upwards in their first sustained rise since early March. The number of that minority of Ontarians who remain eligible for PCR testing who tested positive for COVID infector turned sharply upward at roughly the same time (though that chart couldn’t be updated because those numbers are published only biweekly). The next, more lagging indicator is COVID hospitalizations, which have flattened out after an equally extend decline. 

The most intriguing and somewhat disconcerting news comes from the US CDC biweekly report on the relative incidence of the COVID variants in new US infections. That data shows the most rapid change which we have yet seen in any two-week period. EG.5 (the direct descendant of the more familiar XBB.1.9.2) has jumped into first place as the most common Omicron variant, albeit with little more than a 17% US “market share”. Even more surprising is the unprecedented growth rate of FL.1.5.1 (the direct descendent of XBB.1.9.1) which enjoyed a 29-fold increase over the past 8 weeks, from a miniscule 0.3% to fifth-place 8.6%. While that growth will undoubtedly slow in the weeks ahead, this is the variant now most likely to achieve true dominance, and very quickly. 

While the XBB family now accounts for essentially all new COVID cases and has the inherent capacity to sufficiently evade cellular immunity, infecting many who have been vaccinated and reinfection those who had previous bouts of COVID, our overall “herd immunity” has been sufficiently strong to keep both the actual number of new cases and their severity low. Because that immunity rapidly wanes after six months, the combination of relatively few new infections and very few people bothering to get their free booster shots, we are setting the stage of a major pandemic resurgence in the months ahead, especially in the coming fall when the virus’s inherent seasonality starts working against rather than for us. Variants which quickly achieve dominance almost by definition have a substantial edge over their competitors in ease of transmission, which could result in an FL.1.5.1 bout in your future. The time to pop into a clinic and get your booster is very much now.