Thread by @Cleavon_MD

This 🧵discusses the CDC report of a COVID outbreak in Massachusetts during July 2021. In Q&A format it address vaccination status, hospitalizations, deaths, types of vaccines, symptoms, variants and more. I went through the report line by line. 1/15 cdc.gov/mmwr/volumes/7…

During July 2021, 469 cases of COVID-19 associated with multiple summer events and large public gatherings in a town in Barnstable County, Massachusetts, were identified among Massachusetts residents; vaccination coverage among eligible Massachusetts residents was 69%. 2/15

How many of the 469 infected by COVID were vaccinated?

🔹Vaccinated: 346 (74%)*
🔹Unvaxxed: 123 (26%)

This shows that the vaccine does not prevent transmission. However, the vaccine was created to prevent SEVERE disease, which it does.

*Pfizer, Moderna or J&J vaccine 3/15

What vaccines resulted in breakthrough infections?

All of them:
🔹Pfizer: 159 (46%)
🔹Moderna: 131 (38%)
🔹J &J: 56 (16%)

Of note, the general population in Massachusetts is vaccinated with the following: Pfizer (56%) Moderna (38%) and Johnson & Johnson (7%) 4/15

What variants were detected in those infected?

The Delta Variant. Genomic sequencing of specimens from 133 patients identified in the outbreak of 469 cases showed:
🔹Delta B.1.617.2 - 119 cases (89%)
🔹Delta AY.3 - 1 case (1%)
🔹Unsuccessful -13 cases
covid.cdc.gov/covid-data-tra…

How sick were those infected?

Not very sick. Out of 469 cases, only 5 people were hospitalized. No one died.

Vaccinated: 346 (74%)
🔹274 (79%) symptomatic
🔹4 hospitalized: aged 20-70

Unvaxxed: 123 (26%)
🔹1 hospitalized: age 50-59

Where did people get infected?

Densely packed indoor & outdoor events at venues that included bars, restaurants, guest houses & rental homes. 7/15

What gender and age were those infected with COVID?
🔹Men: 85%
🔹Age: 40 y.o. median (range = <1–76 yrs)

What were the symptoms of breakthrough infection in fully vaccinated people?

274 (79%) reported cough, headache, sore throat, myalgia, and fever

How long after full vaccination did breakthrough infections occur?

Around 86 days after full vaccination: the median interval from completion of ≥14 days after the final vaccine dose to symptom onset was 86 days (range = 6–178 days)

Was there a difference in viral load between vaccinated & unvaccinated people infected?

There was NO difference, meaning it's highly infectious. The amount of virus in the throat of those w/breakthrough infection was similar in vaccinated & unvaccinated.

Update: As of yesterday, the Provincetown COVID Cluster grew to nearly 900 cases. As a result, on July 27, CDC recommended ALL persons, including those fully vaccinated, should wear masks in indoor public settings in areas where COVID-19 transmission is high or substantial.

In sum, vaccines work evinced by low hospitalization rates and deaths. Out of 469 cases, only 4 fully vaccinated people were hospitalized and no one died. However the #DeltaVariant is highly contagious, which is why masks are needed to prevent transmission. 13/15

These headlines are misleading. Vaccines protect against serious illness, but don’t prevent transmission, so WEAR A MASK and #GetVaccinated

Remember VACCINES are only ONE layer of defense against the #DeltaVariant

Lastly, vaccines are working against severe disease. 99% of recent deaths are among the unvaccinated. However vaccines do not prevent transmission, so it's time to change the game plan & wear masks. Hope this thread helps. I used the CDC data to make the pie charts in Excel.