SALEM — The Oregon Health Authority has now released just over two months’ worth of COVID-19 breakthrough case data.

A breakthrough case is where an individual had been fully vaccinated against COVID-19, yet still come down with the virus.

How effective, then, is the vaccine at preventing COVID-19?

In Oregon, the latest breakthrough report, published Thursday, Sept. 30, showed there were a known total of 25,347 breakthrough cases in the state as of Sept. 25. More than 89% of those cases (22,636) have been reported since the OHA started tracking weekly breakthrough data during the week ending July 24. During that time, there were a total of 110,054 COVID-19 cases, meaning 20.6% of cases during that nine-week stretch were people who were vaccinated and 79.4% were unvaccinated.

At that time of the report, there were approximately 2.49 million Oregonians who had been fully vaccinated, which means to this point, of close to 2.5 million vaccinated Oregonians, only about 1.01% have reported getting COVID-19. For comparison’s sake, the percentage of reported COVID-19 cases in Oregon during the pandemic, as of Sept. 25, was about 7.53% of the total population.

In Wallowa County, there have been 61 breakthrough cases reported as of Sept. 25, meaning they made up around 11% of all known cases through that date. Through Sept. 25, there were 3,602 Wallowa County residents who had been fully vaccinated, meaning the rate of a breakthrough case locally is higher than the state rate at 1.7%. The county, on that date, had an overall infection rate of about 7.5%.

Hospitalization and death rates among breakthrough cases are running lower than the overall rate. Of the 25,347 known breakthroughs, there were 1,168 hospitalizations and 218 deaths — rates of 4.6% and 0.86%, respectively. Overall hospitalization and deaths rates have come down since the vaccine’s implementation, and currently are at 5.39% and 1.15%.

Perhaps the starkest difference is change in survival rate among the most susceptible to COVID-19, those 80 and older. Mortality rates for that age group prevaccine varied between about 22-23%. Currently, in a breakthrough-case scenario, the mortality rate is about three times lower at 6.36%.

Of roughly 135,200 individuals 80 and older to get fully vaccinated, just 1,825 are known to have still contracted the virus, with 393 being hospitalized and 116 dying.

Overall, the survival rate of an individual contracting COVID-19 despite getting the vaccine, when looking at how many breakthrough cases and deaths there have been among the vaccinated, is 99.992%.