What 'breakthrough' COVID cases mean for Alaska's seniors

Breakthrough. As in falling through thin ice? No, this one is different, and it may be more important to seniors than any other age group. Here’s how the Centers for Disease Control and Prevention (CDC) put it: “COVID-19 vaccines are effective. However, a small percentage of people who are fully vaccinated will still get COVID-19 if they are exposed to the virus that causes it. These are called ‘vaccine breakthrough cases.’ This means that while people who have been vaccinated are much less likely to get sick, it will still happen in some cases. It’s also possible that some fully vaccinated people might have infections, but not have symptoms (asymptomatic infections).”

Here’s the thing about seniors: As of the second week in July, 56% of ages 12 and older in Alaska had received one or two doses of COVID vaccine. However, 74% of ages 65 and older had received one or two doses of COVID vaccine, according to Alaska’s Vaccine Monitoring Dashboard. In other words, a higher percentage of seniors in Alaska are fully or partially vaccinated than younger age groups. For this reason, breakthrough may be more prevalent among seniors.

There’s more to glean about breakthrough in Alaska seniors from a recently completed study reported in the State of Alaska Epidemiology Bulletin (epidemiology is the study of the distribution of diseases in populations). From February 1 to June 30, 2021, 656 cases of COVID-19 infection were classified as Alaska vaccine breakthrough cases – all these cases were among people who were fully vaccinated.

Note that vaccine breakthrough is rare. Those 656 cases represented only 0.2% of all fully vaccinated Alaskans as of June 30, 2021. Unfortunately, the bulletin does not report the percentage breakdown of these cases by age, however the study does note that the median age in years is 47, and that the age range is from 16 to 96(!). This appears to be predominantly an older crowd.

The vaccines we use in the United States protect against breakthrough very well, and are particularly good at preventing a breakthrough infection from progressing to hospitalization or death. The CDC reports that as of July 6, 2021, over 157 million U.S. residents were fully vaccinated. The CDC does not report how many breakthrough cases there have been nationwide, but they do report that during the same period a total of 5,186 patients who suffered a breakthrough infection were hospitalized or died from it. Compared to 157 million vaccinated residents this is a miniscule number. On the other hand, fully 75% of those who were hospitalized or died were 65 years of age or older. That’s a red flag for us.

But there is one factor that may make virus breakthrough cases among the fully vaccinated more common – the Delta variant. As explained on the Yale Medicine website, “A major concern right now is Delta, a highly contagious (and possibly more severe) SARS-CoV-2 virus strain, which was first identified in India in December. It then swept rapidly through that country and Great Britain as well. The first Delta case in the United States was diagnosed a couple of months ago (in March) and it is now the dominant strain in the U.S.”

And of course, it is here in Alaska. Back on June 24, Dr. Anne Zink, Chief Medical Officer for the State of Alaska, announced to a Zoom full of journalists that, “... we are seeing sort of widespread infection [of the Delta variant]. So, we’re seeing it in multiple regions, including Anchorage, Mat-Su, the Interior, Southeast, Northern, and Gulf Coast regions.”

Since then, it has become even more widespread across the state. You might ask, “So what?”. Joe McLaughlin, State Epidemiologist and Chief of the Alaska Section of Epidemiology, explained in a June 30 press conference, “The Delta variant based on the currently available data appears to be about 50% more transmissible than the B.1.1.7 variant. And remember that the B.1.1.7 variant was about 50% more transmissible than the original wild type strain that emerged out of Wuhan. If all those data are true and accurate, it is likely the most transmissible highly transmissible variant that we’ve seen so far.”

What to do? McLaughlin states bluntly, “...certainly, the number one best way to prevent acquiring the Delta variant and any other variant of the source covid-2 virus is through vaccination.”

In response to a question at a late-June public forum, Dr. Zink, Alaska Chief Medical Officer, addressed one thing vaccinated seniors can do: “If you’re going into a highly crowded bar, where there’s lots of people without masks hanging out, that’s going to be high risk, particularly you know, someone who is older, in your 70s [or older], so consider wearing a mask when you’re going into those indoor spaces.”

Author Bio

Lawrence D. Weiss is a UAA Professor of Public Health, Emeritus, creator of the UAA Master of Public Health program, and author of several books and numerous articles.

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