35 of the 92 people (38%) who attended services at a rural Arkansas church March 6–11 tested positive for the coronavirus, ultimately killing three

While the infographic reports at least 35 positives among the 92 attendees, the article also reports 35 positives among the 45 that were tested, yielding a range between the two attack rates, 38%-78%.

Of note:

  • Only 45 people were tested.
  • Testing varied among age groups (for some reason they only list 3 age groups; the only value I can derive is that testing was higher among adults than children).
  • 2 people were exposed but not successfully contacted, so they use 92 as their total number exposed instead of 94.
  • No mention of the total number of suspected secondary exposures, how many of those exposed were successfully contacted, or how many consented to testing (they only indicate that there are 26 known positive cases from secondary exposure).
  • It is unclear, but they only mention contact tracing for the 35 known positive cases (relevant because not everyone exposed was tested).

"Overall, 94 persons attended church A events during March 6–11 and might have been exposed to the index patients or to another infectious patient at the same event; among these persons, 92 were successfully contacted and are included in the analysis. Similar proportions of church A attendees were aged ≤18 years (35%), 19–64 years (35%), and ≥65 years (30%) (Table 1). However, a higher proportion of adults aged 19–64 years and ≥65 years were tested (72% and 50%, respectively), and received positive test results (59% and 50%), than did younger persons. 45 persons were tested for SARS-CoV-2, among whom 35 (77.8%) received positive test results (Table 2)."

"Among the 35 persons with laboratory-confirmed COVID-19, seven (20%) were hospitalized; three (9%) patients died. At least 26 additional confirmed COVID-19 cases were identified among community members who, during contact tracing, reported contact with one or more of the 35 church A members with COVID-19 as an exposure. These persons likely were infected by church A attendees. Among these 26 persons, one was hospitalized and subsequently died. Thus, as of April 22, 61 confirmed cases (including eight [13%] hospitalizations and four [7%] deaths) had been identified in persons directly and indirectly associated with church A events."

“...attack rates were estimated by dividing the total number of persons with laboratory-confirmed COVID-19 by the number of persons tested for SARS-CoV-2 and by the number of persons who attended church A during March 6–11, respectively."

"The estimated attack rate ranged from 38% (35 cases among all 92 church A event attendees) to 78% (35 cases among 45 church A event attendees who were tested for SARS-CoV-2)."

https://www.cdc.gov/mmwr/volumes/69/wr/mm6920e2.htm

/r/science Thread Link - cdc.gov