New data provide further evidence of vaccine effectiveness

Today, OHA’s Medical Director of Respiratory Viral Pathogens Dr. Melissa Sutton spoke with medical officials from across the state to provide an update on the COVID-19 situation in Oregon. Here’s what you need to know.

New CDC data displays further proof of vaccine effectiveness

Dr. Sutton highlighted information from the Centers for Disease Control and Prevention (CDC) new vaccine effectiveness study, which shows all three vaccines ward off hospitalizations from COVID-19.

The study analyzed data collected through the COVID-19-Associated Hospitalization Surveillance Network (COVID-NET) — a CDC population-based surveillance system that tracks severe COVID-19 cases in Oregon and 13 other states.

The study revealed that, among 7,000 patients ages 65 and older, the Pfizer and Moderna vaccines reduced the risk of hospitalization by 91–96% and the Johnson & Johnson vaccine reduced the risk of hospitalization by 84–85%.

Dr. Sutton said this data is important for several reasons.

“First, they demonstrate that COVID-19 vaccines are working as well in the real world as they did under clinical trial conditions at preventing severe COVID-19,” said Dr. Sutton. “Second, there was no evidence of decreasing effectiveness over time. Third, they demonstrate that COVID-19 vaccines work exceptionally well in elderly adults and we believe they will work as well or better in younger people.”

Dr. Sutton said these data prove that the best way to avoid serious illness and death from COVID-19 is to get vaccinated.

Oregon’s latest COVID-19 vaccine breakthrough report highlights vaccine effectiveness

Dr. Sutton also took time to discuss OHA’s July COVID-19 vaccine breakthrough report. This report analyzes all of the COVID-19 vaccine breakthrough cases — instances in which an individual receives a positive COVID-19 test at least 14 days following the completion of a COVID-19 vaccine series —identified in Oregon.

Through June 30, Oregon had identified 4,196 such cases.

“The number of vaccine breakthrough cases remains very small when compared to the more than 2.3 million Oregonians who have completed their COVID-19 vaccination series,” said Dr. Sutton. “Of the 55 COVID-19-associated deaths reported in July, 91% were among people who were unvaccinated.”

Dr. Sutton referenced the graph below to display how much less common COVID-19 infection was among vaccinated individuals before reiterating the need for more Oregonians to get vaccinated.

Delta now the dominant variant in Oregon

Dr. Sutton concluded with a stark remark about the Delta variant, otherwise known as B.1.617.2.

“It is now the dominant variant circulating in Oregon and nationwide,” said Dr. Sutton. “It is 2-3 times more infectious than early COVID-19 variants. For unvaccinated individuals, the risk of COVID-19 has literally never been greater.” 

Variants are defined by the CDC as genetic variations of the SARS-CoV-2 virus — the virus that causes COVID-19. The Delta variant is classified by the CDC as a “variant of concern,” which is the name for a category of variants noted for their ability to spread more easily, cause more severe disease or evade testing, therapies or vaccination.  As Dr. Sutton mentioned, the Delta variant falls into this category because of its ability to spread more rapidly than other variants.

You can learn more about the Delta variant here. OHA also keeps track of Oregon’s variant information on its dashboard here.

Get vaccinated

Vaccination remains the safest and most effective way for all people in Oregon to get back to doing the things they love. If you are 12 or older, visit OHA’s Find a COVID-19 Vaccine in Oregon webpage to schedule your vaccine appointment today.

You can watch a recording of today’s media availability below.


  1. Today’s slides
  2. Dr. Sutton’s talking points
  3. OHA press release on CDC data