Researchers predict downward trend for Hawaii COVID-19 cases

A forecast for Honolulu’s peak number of daily coronavirus cases has been revised downward due to recent data and a combination of other factors, including new restrictions and fewer travelers.

The new model released Sunday by the Hawaii Pandemic Applied Modeling Work Group is based on the past 12 days of data, along with other factors, and now forecasts daily COVID-19 cases for Honolulu County will continue on a downward trend through the end of September.

This reflects a turnaround from the situation in late July and early August, when a peak of up to 3,700 cases was forecast for early October due to the highly transmissible delta variant, according to University of Hawaii mathematics professor Monique Chyba, based on the math and known variables at the time.

Modelers have determined there was a peak of 739 cases in Honolulu in late August, and then a shift, and numbers have since trended down. How much lower they will go, however, depends on various factors, including vaccination rates and changes in people’s behavior.

“It can shift either way very quickly,” said Chyba.

In the most optimistic scenario, with higher vaccination rates, daily case counts for Honolulu County could fall to the range of 127, and in the worst-case scenario, with lower vaccination rates, they fall to 237. There’s a possibility they might fall somewhere in between, in the vicinity of 191.

HiPAM, upon request at a recent Honolulu City Council hearing, has estimated the potential impact of the Safe Access Oahu program could reduce cases by about 30% in the next 10 days. The Safe Access Oahu program, which requires proof of vaccination or a negative COVID test for employees and patrons of restaurants, bars, and other establishments, went into effect on Oahu on Sept. 13.

The model was based on the assumption that unvaccinated and vaccinated individuals would be interacting, on average, 50% less, resulting in fewer transmissions.

Honolulu Mayor Rick Blangiardi today announced that the county will extend restrictions on large gatherings through Oct. 19.

On Maui County, daily coronavirus cases numbers have been fluctuating, HiPAM noted, but the model shows an overall downward trend.

Maui’s SaferOutside restrictions went into effect last Wednesday, reducing social gathering sizes to five indoors, and 10 outdoors, and requiring proof of vaccination for patrons to enter restaurants, bars, and gyms.

HiPAM generated a model assuming interactions between vaccinated and unvaccinated individuals would be reduced by 50%, on average, and predicts daily COVID cases on Maui County dropping from a peak of 114 to 18 to 21 cases.

While the forecast is looking better overall, Chyba said it is not time to celebrate or declare a victory yet.

“It seems that mitigations are doing their job,” she said, “but the issue is that there are still a lot of people unvaccinated and since we cannot eradicate the delta once we reopen, it will have its course again. It is not a simple situation.”

Forecast models for the four major counties, including Kauai, Maui, and Hawaii, all reflect a downward trend over the next 10 days, and appear to be on track for the most optimistic case scenarios. But caution and monitoring are still necessary, HiPAM said.