Thread by @DrEricDing

Damn—An unvaccinated health care worker set off a #COVID19 outbreak at a nursing home where most residents were vaccinated—dozens of infections, including 22 cases among residents/staff who were already fully vaccinated. 1 death in a nursing resident. 🧵
nytimes.com/2021/04/21/hea…

2) “The study estimated that the vaccine, identified as Pfizer-BioNTech, showed effectiveness of 66 percent for residents and 75.9 percent for employees, and were 86 percent to 87 percent effective at protecting against symptomatic disease."

3) Most of those who were infected with the coronavirus despite being vaccinated did not develop symptoms or require hospitalization, but one vaccinated individual, who was a resident of the nursing home, died, according to the study released by the CDC.

4) Altogether, 26 facility residents were infected, including 18 who had been vaccinated, and 20 health care personnel were infected, including four who had been vaccinated. Two unvaccinated residents also died.

5) “To protect skilled nursing facility residents, it is imperative that health care providers, as well as skilled nursing facility residents, be vaccinated,” the authors of the Kentucky study wrote.

6) Vaccinated residents and health care workers at the Kentucky facility were less likely to be infected than those who had not been vaccinated, and they were far less likely to develop symptoms.

7) The study estimated that the vaccine, identified as Pfizer-BioNTech, showed effectiveness of 66 percent for residents and 75.9 percent for employees, and were 86 percent to 87 percent effective at protecting against symptomatic disease.

8) Was there a variant? Oh yes.

The outbreak involved a variant of the virus that has multiple mutations in the spike protein, of the kind that make the vaccines less effective.

9) Variant is called “R1”. In the Kentucky outbreak, the virus variant is not on the C.D.C.’s list of those considered variants of concern or interest. But, the study authors note, the variant does have several mutations of importance: ...

10) D614G, which demonstrates evidence of increased transmissibility; E484K in receptor-binding domain of the spike protein, which is also seen in B.1.351, & P.1. of Brazil; & W152L, which might reduce effectiveness of neutralizing antibodies.

11) “Four possible reinfections were identified (one resident and three HCP); of these, one HCP was vaccinated. All four persons experienced symptomatic illness.

12) One resident was infected 300 days earlier and had nine consecutive negative RT-PCR tests before reinfection, including two within 30 days of the outbreak. This resident was hospitalized and died.

13) “In a SNF with 90.4% of residents vaccinated, an outbreak of COVID-19 occurred after introduction from an unvaccinated, symptomatic HCP. WGS identified an R.1 lineage variant, characterized by E484K and other mutations within the spike protein.

14) “Attack rates were three to four times as high among unvaccinated residents and HCP as among those who were vaccinated; vaccinated persons were significantly less likely to experience symptoms or require hospitalization”. cdc.gov/mmwr/volumes/7…

15) to be clear, the vaccine has saved MANY MANY lives. But we need to **BREAK THE CHAINS OF TRANSMISSION** and reduce transmission. And to do that, we need more people vaccinated. Plain and simple.

https://twitter.com/DrEricDing/status/1384880091277189122

16) that said, we know some breakthrough cases can happen with vaccines. #B117 and AstraZeneca is usually good. But it’s not perfect. But AZ shows 29% efficacy against asymptomatic transmission of B117. This is why we still wear masks.

https://twitter.com/DrEricDing/status/1377319936968826880