Thread by @AbraarKaran

THREAD
1/ #Covid19 super-spreading event from a bar in Vietnam; this report is from a party for St Patrick's day in which one guest infected 12 others at a poorly ventilated crowded bar.

Genome sequencing analysis helped to confirm this.
wwwnc.cdc.gov/eid/article/27…

2/ They note that asymptomatic secondary spread occurred to people who were not at the bar as well.

Indoor, crowded, poorly ventilated spaces without masks are dangerous; these types of cluster spreading events are propagating this epidemic.

3/ While this may happen at bars, we have seen the same in others settings as well.

Sports games--> recent CDC report of an outbreak at a hockey game

https://twitter.com/AbraarKaran/status/1318050866583228416?s=20

4/ We are well aware of the significant outbreak at an indoor call center in South Korea from earlier in the epidemic.

wwwnc.cdc.gov/eid/article/26…

5/ And of this outbreak from an indoor restaurant in China associated possibly with an air conditioning unit/ poor air exchange.

wwwnc.cdc.gov/eid/article/26…

6/ And this @JAMA_current investigation on viral spread throughout this bus, well beyond 6 feet of distance from the index case.

jamanetwork.com/journals/jamai…

7/ We have seen a number of reports of transmission on airplanes as well; most if not all were in the era *before masks*! I have yet to see any large or small plane outbreak since universal masking on flights.

wwwnc.cdc.gov/eid/article/26…

wwwnc.cdc.gov/eid/article/26…

8/ In the US, we had a notable outbreak at summer camps in Georgia.

Here too we had limited mask use; there was singing and cheering, crowding indoors; and asymptomatic spread.

cdc.gov/mmwr/volumes/6…

9/ Adding to the singing indoors...the infamous choir outbreak from Washington in which 53 cases were identified out of 61 people who attended; 3 were hospitalized and 2 died.

cdc.gov/mmwr/volumes/6…

10/ And in South Korea, we saw #covid19 outbreaks associated with high-intensity fitness/dance classes; we have seen others since then as well.

wwwnc.cdc.gov/eid/article/26…

11/ Such as this more recent #covid19 outbreak in a spin class in Hamilton, Canada in which masks were not used during the class.

forbes.com/sites/victoria…

12/ One that is particularly unfortunate is the wedding outbreak from the country of Jordan early in the epidemic, in which the father of the bride was the index case, had greeted most guests at the door; and propagated a super-spreading wedding.

wwwnc.cdc.gov/eid/article/26…

13/ Similarly we saw another more recent wedding outbreak from Maine, which led to subsequent outbreaks throughout the state, including in a jail. Again-- indoors, no masks, dancing, singing etc

npr.org/2020/09/16/913…

14/ We all at this point remember #covid19 and ships/cruises.

Re-upping this CDC investigation of the Yokohama ship-- attack rates highest in more crowded cabins; asymptomatic spread-- the patterns repeat themselves.

wwwnc.cdc.gov/eid/article/26…

15/ And then we have religious gatherings.

In the US, we have seen #covid19 outbreaks at churches, where singing, socializing, eating together etc propagated spread. This was predictable; we didn't stop it.

cdc.gov/mmwr/volumes/6…

16/ Additionally, we had an outbreak in Boston over the summer at a hospital in which the break room was the location of spread where masks were removed to eat/rest etc; transmission can/will happen when we least expect it

boston.cbslocal.com/2020/07/27/spr…

17/ And then more recently this fall with multiple outbreaks across hospitals in Massachusetts, many linked to crowded working conditions that make it nearly impossible to physically distance + lack of regular testing for staff--> asymptomatic spread

bostonglobe.com/2020/10/06/met…

18/ This is all to say that there are very clear take-aways from all that we know; we know so much more now than we did in March or April.

And we are clearly headed into a third surge of #covid19 in the United States.

https://twitter.com/AbraarKaran/status/1318061380113698826?s=20

19/ Learning from all of these past outbreaks:
-close/ prolonged indoor contact is high risk
-MASKS WORK!
-singing/dancing/high intensity activity--> likely more droplets and aerosols emitted + more inhalation--> more spread of disease
-Asymptomatic spread is very real

20/ This virus has many weak points.

It spreads largely through clusters in which few people infect many people and many people don't necessarily infect any people.

So if we can stop large outbreaks, we can drive transmission down.

This is a key part of #covid19 control.

21/ Addendum: Need to point out disproportionate impact on frontline workers that were forced to keep going without protection while we “stayed home”— here described outbreak at a meat processing plant— over 900 infections in 5 weeks (1 in 4 employees)

cdc.gov/mmwr/volumes/6…

22/ And this.

Leaders talk a lot about protecting the vulnerable, but no $$ where their mouths are.

washingtonpost.com/national/osha-…