COVID Breakthrough Data
Compared to what?
CNN’s headline “Less than 0.001% of fully vaccinated Americans died after a Covid-19 breakthrough case, CDC data shows” sparks more questions than it answers.
The story is much better but still uses numbers in a less-than-helpful manner.
Less than 0.004% of people fully vaccinated against Covid-19 experienced a breakthrough case resulting in hospitalization and less than 0.001% died from the disease, according to the latest data from the US Centers for Disease Control and Prevention. The data highlights what leading health experts across the country have highlighted for months: Covid-19 vaccines are very effective at preventing serious illness and death from Covid-19 and are the country’s best shot at slowing the pandemic down and avoiding further suffering.
So, aside from numbers, that’s not new news. But how do the 0.004% and 0.001% figures compared to those for unvaccinated people?
These numbers seem good:
The CDC reported 6,587 Covid-19 breakthrough cases as of July 26, including 6,239 hospitalizations and 1,263 deaths.
At that time, more than 163 million people in the United States were fully vaccinated against Covid-19.
But, again, compared to what? What are the rates for the unvaccinated?
This is useful information:
Most of the breakthrough cases — about 74% — occurred among adults 65 or older.
But, you might be asking yourself, how does this compare to the unvaccinated?
Alas, part of the problem is that we’re no longer collecting data on less serious cases:
Since May, the CDC has focused on investigating only hospitalized or fatal Covid-19 cases among people who have been fully vaccinated. The agency says the data relies on “passive and voluntary reporting” and are a “snapshot” to “help identify patterns and look for signals among vaccine breakthrough cases.”
And this messaging is confusing:
The agency shared a study this week that showed the Delta variant produced similar amounts of virus in vaccinated and unvaccinated people if they get infected. Experts continue to say that vaccination makes it less likely you’ll catch Covid-19 in the first place. But for those who do, the findings suggest they could have a similar tendency to spread it as unvaccinated people.
At least the media coverage of this is probably over-emphasizing the transmission rates and drastically under-emphasizing the radically different baselines. But it probably makes sense to do this, in that it’s seemingly in service of justifying the new guidelines, which require the vaccinated to wear masks in high-transmission localities.
The good news is that the wave of scary news on the Delta variant seems to be having positive effects:
Amid concerns over the rising cases and the dangerous strain, the country has seen a steady rise in the pace of vaccinations in the past three weeks — and an even sharper increase in states that had been lagging the most, according to a CNN analysis of CDC data. The seven-day average of new doses administered in the US is now 652,084, up 26% from three weeks ago.
The difference is even more striking in several southern states: Alabama’s seven-day average of new doses administered is more than double what it was three weeks ago. The state has the lowest rate of its total population fully vaccinated in the US, at roughly 34%.
Arkansas, with just 36% of its population fully vaccinated, has also seen its average daily rate of doses administered double in the last three weeks.
Louisiana, which had by far the most new Covid-19 cases per capita last week and has only fully vaccinated 37% of its population, saw daily vaccination rates rise 111% compared to three weeks ago.
Meanwhile, Missouri, which has been among the hardest-hit states in the latest Covid-19 surge, now has a daily average of new vaccinations 87% higher than three weeks ago.
Trying to dig into the CDC data myself, the overall numbers are a mixed bag:
That slightly less than a majority of the population is not fully vaccinated looks bad on first glance but at least 57.5% have had at least one shot; it’s unclear how many of those are one-and-done versus planning on getting the second dose. Still, half-vaxxed is more than half-protected. And the numbers are much better, still, when we look at the over-12 population, since those are the only ones eligible. That the over-12 and over-18 numbers are virtually the same is interesting but I’m not sure what to make of it. More encouragingly of al is that the over-65s are much, much more likely to be vaccinated, with almost 90% at least half-vaxxed. Since they’re far and away the most vulnerable demo, that’s good.