Sunday, May 28, 2023

CDC Update: Rapid Assessment Of COVID Outbreak At 2023 EIS Conference


Just over a month ago (Apr 24-27th) the CDC held a large (virtual and in-person) 2023 Epidemic Intelligence Service (EIS) Conference in Atlanta, GA which was attended by roughly 1800 individuals (mostly EIS officers, Laboratory Leadership Service (LLS) fellows, and other trainees).

A few days after the conference had ended it was widely reported that the CDC was investigating `several dozen' COVID infections reported by attendees.

Given the irony of the situation - a superspreader event among a conference of disease detectives - it received a lot of press. 

Late Friday the CDC published the following media statement which expands the number of people infected at this conference (based on a voluntary survey) to over 180 people (roughly 1 in 8).

I'll have a brief postscript after the break. 

Update on Rapid Assessment of SARS-CoV-2 Transmission at 2023 EIS Conference
Media Statement

For Immediate Release: Friday, May 26, 2023
Contact: Media Relations
(404) 639-3286

CDC’s 2023 Epidemic Intelligence Service (EIS) Conference brought together approximately 1,800 in-person and 400 virtual attendees during April 24–27, 2023, in a hotel conference facility in Atlanta, Georgia. This annual, multi-purpose event consists of both traditional scientific presentations, as well as one-on-one and small-group recruitment events for incoming EIS officers and staff from CDC and state and local health departments.

On Thursday, April 27, several in-person attendees notified conference organizers that they had tested positive for SARS-CoV-2, the virus that causes COVID-19. That same day, EIS leaders made an announcement at the conference about potential cases and took action to reduce further spread connected with the conference and related events. After the conference ended, CDC received additional reports of attendees testing positive for SARS-CoV-2 and worked with the Georgia Department of Public Health to initiate a rapid assessment. The goals were to learn more about transmission that occurred and add to our understanding as we transition to the next phase of COVID-19 surveillance and response.

The rapid assessment team surveyed in-person attendees from May 5–12 about their COVID-19 testing results and healthcare-seeking behavior. Among 1,443 survey respondents (over 80% of the in-person attendees):
  • 181 (13%) respondents reported testing positive for SARS-CoV-2
  • Of those who reported testing positive, 52% reported no known prior COVID-19 infection
  • 1,435 (99.4%) of respondents reported at least one COVID-19 vaccine dose
  • 49 (27%) of the respondents who tested positive received antiviral medications
  • 70% of respondents reported not wearing a mask; the event coincided with a period of low COVID-19 Community Levels, where masking is not recommended in CDC guidance
  • None were hospitalized
These findings underline the importance of vaccination for protecting individuals against severe illness and death related to COVID-19. Nearly every respondent reported receiving at least one COVID-19 vaccine dose, and none of the 181 people who reported testing positive were hospitalized.

Not surprisingly, there was an increased chance of infection the longer participants attended the conference and the more events they participated in. Specifically, respondents who tested positive reported attending the conference on average for all four days, and the risk of infection was 70% greater among those who attended for three or more days versus those who attended for two or fewer days.

Again, the findings of this rapid assessment support previous data that demonstrate that COVID-19 vaccines, antiviral treatments, and immunity from previous infection continue to provide people with protection against serious illness. CDC continues to recommend that everyone ages six months and older stay up to date with all COVID-19 vaccines, including receiving an updated vaccine. COVID-19 vaccines are effective at protecting people from getting seriously ill, being hospitalized, and dying.

          (Continue . . . )

This is a reminder that even though the COVID crisis has been declared over, the risk of infection - particularly when attending large public venues - remains.  Given the continued evolution and spread of COVID variants, this is unlikely to be the last such outbreak. 

While this is the first detailed statement we've seen, hopefully someone is working on a more thorough analysis of this event, as we still lack a lot of details, including:

  • The age demographics of attendees (since this was a training conference, I suspect it will skew towards younger adults, but I'm guessing).
  • 70% of attendees reportedly did not wear masks, but doesn't tell us how many of those who were masked were infected
  • What percentage of attendees actually tested themselves (and how often) after the conference?  
  • A better breakdown of vaccination status than (99.4%) reporting at least one COVID-19 vaccine dose
  • And frankly, an 80% survey response rate from a conference of disease detectives is a bit underwhelming.
While I fully support the idea that COVID vaccines likely reduced the severity of these infections - at least in what was likely a younger, and relatively healthy cohort - I personally believe that masking remains an appropriate countermeasure, particularly in a crowded venue like this. 

A quaint notion that was apparently still shared by 30% of the attendees of this conference.