HERE IT IS: The actual data on which the CDC’s new mask guidance is based.

This isn’t a leaked powerpoint of uncertain provenance. This is the genuine article, a CDC study of an outbreak several weeks ago in Provincetown, Massachusetts, that caused the agency to scramble and recommend masking for every American in a community with substantial transmission.

Having now read through it, I have the same reaction as Greg Pollowitz: “[W]hat the CDC data on Provincetown actually shows is that even under perfect conditions for a superspreader event, the vaccine works spectacularly well.”

The study tracks a nasty outbreak in P-town over the first two weeks of this month. On July 3, cases in Barnstable County were rock-bottom at zero per 100,000 residents due in large part to the state’s high vaccination rate of 70+ percent partially immunized and 60+ percent fully immunized. Two weeks later, after locals partied on July 4 and attended a series of summer events, cases had exploded to 177 per 100,000 over the previous 14 days. Many of those infections were afflicting fully vaccinated people.

That’s not good news. But is it as terrible as the reporting has cracked it up to be?

Approximately three quarters (346; 74%) of cases occurred in fully vaccinated persons (those who had completed a 2-dose course of mRNA vaccine [Pfizer-BioNTech or Moderna] or had received a single dose of Janssen [Johnson & Johnson] vaccine ≥14 days before exposure). Genomic sequencing of specimens from 133 patients identified the B.1.617.2 (Delta) variant of SARS-CoV-2, the virus that causes COVID-19, in 119 (89%) and the Delta AY.3 sublineage in one (1%). Overall, 274 (79%) vaccinated patients with breakthrough infection were symptomatic. Among five COVID-19 patients who were hospitalized, four were fully vaccinated; no deaths were reported. Real-time reverse transcription–polymerase chain reaction (RT-PCR) cycle threshold (Ct) values in specimens from 127 vaccinated persons with breakthrough cases were similar to those from 84 persons who were unvaccinated, not fully vaccinated, or whose vaccination status was unknown (median = 22.77 and 21.54, respectively).

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Which brings us to the first wrinkle in the data. How much of the P-town outbreak is due to the circumstances being absolutely ideal for a mass outbreak?

Click to enlarge.

As Byron York tweets, “Not a Trump hotspot. The proper response is not to blame Blue America for outbreak but for those finger-pointing commentators to be a little more circumspect, a little less Trump-obsessed, a little more reasonable. Would be good idea.”

But the narrative is all, alas.

Related: A gay rights activist explains why the CDC’s Provincetown study may be fatally flawed.