Friday, OHA released its latest COVID-19 forecast, which showed lower transmission of the virus through late April and projects fewer hospitalizations and daily cases through June 1. According to the model, the effective reproduction rate — the expected number of secondary cases that a single case generates — was estimated to be 0.86 through April 28. At that same level of transmission, daily cases would decline to 140 per 100,000 people, which would amount to an average of 420 new daily cases with 17 fewer daily hospitalizations by June 1. If transmission increases by 20%, new cases would decline more gradually to 195 per 100,000 people, which would amount to an average of 590 daily cases and 26 fewer hospitalizations. The report also addressed the impact vaccinations have had on substantially slowing the spread of COVID-19 in Oregon. According to the report: “Vaccine immunity is helping prevent further spread of COVID-19. If we remove all of those who have vaccine immunity from the model calculations and look at the rate of infection, we see each infection spreading on average to 1.12 other people.” Without any vaccine immunity, the estimated effective reproduction rate “would be 1.12 instead of 0.86, and new infections would still be increasing.” More than 2 million Oregonians have received at least one dose of a COVID-19 vaccine and 1.5 million have completed a vaccine series.
