With BA.4 and BA.5 now dominant, OHSU forecasts mid-July peak for current COVID hospitalization wave

PORTLAND, Ore. (KGW) — Oregon’s current COVID-19 wave has been lengthened by the arrival of a series of new and increasingly transmissible strains of the omicron variant, but Oregon Health and Science University’s forecast predicts — at least for the moment — that the peak is coming soon.

The latest forecast, released Thursday afternoon, predicts a peak of 479 statewide hospitalizations on July 12. Hospitalizations stood at 423 as of Wednesday, according to the Oregon Health Authority.

The forecast was delayed from last week to give OHSU’s Peter Graven more time to incorporate data about the BA.4 and BA.5 versions of the omicron variant, which have become dominant at the national level and are rapidly growing in Oregon.

Doctors are certainly seeing the effects of BA.4 and BA.5, which is proving to be highly contagious.

“They’re as transmissible as measles which is one of the most contagious viruses out there. I think most people can expect that they will get infected at some point,” said Dr. Katie Sharff, Chief of Infectious Disease with Kaiser Permanente Northwest, who expects 93-95% of the population will eventually contract COVID-19.  

Oregon’s current wave began in April with a steady rise in both cases and hospitalizations, initially caused mostly by the BA.2 strain. The BA.2.12.1 version accounted for only a small percentage of cases at first, but began to overtake BA.2 in May.

By early June, Graven was predicting a peak of 313 hospitalizations around the middle of the month, but the wave ended up outpacing that forecast, a change that Graven later attributed in part to the rise of BA.2.12.1.

Oregon’s 7-day average for new cases has fluctuated within a range of about 1,400 to 1,900 since the middle of May, and hospitalizations began to climb again in late June after holding at around 300 for a few weeks.

According to Graven’s latest forecast, the earlier omicron strains have already begun to recede, meaning the latest spike in the wave is primarily driven by BA.4 and BA.5. Hospitalizations driven by those two strains in particular are expected to peak a bit later in the month, according to the forecast.

“I don’t think this is going to run into a massive surge, but I do think it’s going to remain [at] elevated infection levels for another month here,” Graven told KGW.

The two newest strains are the most transmissible yet, and they’re better at evading immune defenses, which means they’re contributing not only to a rise in infections among people who have never had COVID, but also reinfections among people who have already been sick.

And with BA.4 and BA.5, the symptoms may be a little stronger than in previous variants.

“I have heard anecdotally many people who have contracted this BA.4 and 5 are having a more severe flu-like illness; not bad enough that they need to be in the hospital, but they do not feel well with fever sore throat, feeling very poorly,” said Sharff. “All that being said, vaccinations are still the number one tool to prevent severe disease and hospitalizations.”

The latest variants will eventually wane, and after that, Graven is not yet seeing another variant on the horizon.

“That’s the first time we’ve had that in a little while. Now, I know there will be another variant, but we just don’t have our eyes set on one yet … so that’s a little bit of hope,” said Graven.

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