Breakthrough COVID cases are rising in Alaska. Here’s why, and why vaccines are still ‘amazing.’

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This graph, from a recent state report, shows the share of vaccinated vs. unvaccinated COVID cases. (Alaska Division of Public Health)

COVID-19 cases among fully vaccinated Alaskans are climbing, and the delta variant is just one reason. It’s a complicated set of facts that public health officials have to explain without detracting from their main message – that the vaccine is their best tool for curbing the pandemic and still provides excellent protection.

Alaska recorded 17 COVID deaths in July. Four of those people were fully vaccinated. Of COVID-19 cases requiring hospitalization in July, 19% of the patients were vaccinated.

At a steady clip, it takes State Epidemiologist Dr. Joe McLaughlin about 20 minutes to talk through a recent state report that outlines breakthrough infection cases in Alaska and why they’re going up.

One factor is that an individual’s immune response from the vaccine weakens over time. That’s the reason vaccine booster shots are likely coming this fall. It’s been months since many Alaskans got their shots, and now their waning immunity is up against the delta variant of the virus.

Alaska State Epidemiologist Joe McLaughlin.

“For people who were vaccinated more than 150 days ago, the vaccine effectiveness is about 73% against SARS CoV-2 infection,” McLaughlin said, using the formal name of the virus. “If you’re looking just at the delta variant, then (vaccine effectiveness) drops down to about 66%.”

Another factor is not a limitation of the vaccine but a math issue: Month by month, more Alaskans have become fully vaccinated. As the vaccinated population grows, so does the possibility that more vaccinated people will become infected.

The state’s data show that almost 30% of July’s new COVID-19 cases were among vaccinated people. But McLaughlin suspects a difference in who is getting tested. Maybe vaccinated people are more likely to seek the swab, he said, than people who haven’t gotten vaccinated.

“If that’s true, then what you’re going to see is a higher proportion of cases that get reported into the health department are going to be in that fully vaccinated group because they’re more likely to get tested,” McLaughlin said. “If you don’t (get a) test, you’re not going to find it, and you’re not going to get it reported to the health department.”

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The voluntary nature of testing could be highlighting the breakthrough cases, but the growth in breakthrough is real. 

“The good news, however, is that the vaccine effectiveness at preventing hospitalization is still very robust, probably in the 90 plus percentage range,” McLaughlin said. “And then the vaccine effectiveness against death due to COVID-19 illness is even higher, probably in the mid to high 90 percentage range.”

Anchorage economist Jonathan King, who writes a newsletter about the state of the pandemic, said the evolving nature of the virus and the science makes for a tricky public health message.

“There’s already a strong movement against the vaccines, and so it makes it harder to sell the story that the vaccines are effective. Which they are,” he said. “It is a challenging thing to both try to convince people of something, and have the story changing about that thing at the same time.”

Alaska’s chief medical officer, Dr. Anne Zink, used the power of illustration to make the case during a recent public information session. Zink works shifts in the Emergency Department of Mat-Su Regional Medical Center. It’s not uncommon, she said, for a couple to arrive in the ER with one unvaccinated spouse who is very sick and struggling to breathe. The other spouse is vaccinated and fine.

“It’s just striking,” Zink said, “So while (the vaccine) is not perfect — we see vaccine breakthrough cases, we see vaccine hospitalizations, we see deaths — it still is doing an amazing job at tempering this surge, minimizing the surge on people getting sick, hospitalized and dying.”

RELATED: Anchorage School District suspends multiple bus routes due to COVID-related driver shortage

Liz Ruskin is the Washington, D.C., correspondent at Alaska Public Media. Reach her at Read more about Liz here.

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