White House Is Not Contact Tracing ‘Super-Spreader’ Rose Garden Event
Since President Trump’s Covid diagnosis, numerous associates have tested positive, but the White House has not aggressively investigated the outbreak.
Despite almost daily disclosures of new coronavirus infections among President Trump’s close associates, the White House is making little effort to investigate the scope and source of its outbreak.
The White House has decided not to trace the contacts of guests and staff members at the Rose Garden celebration 10 days ago for Judge Amy Coney Barrett, where at least eight people, including the president, may have become infected, according to a White House official familiar with the plans.
Instead, it has limited its efforts to notifying people who came in close contact with Mr. Trump in the two days before his Covid diagnosis Thursday evening. It has also cut the Centers for Disease Control and Prevention, which has the government’s most extensive knowledge and resources for contact tracing,
out of the process.
Contact tracing is an essential piece of any outbreak investigation and is a key to stopping the virus from spreading further, especially after a potential “super spreader” event where many people may have been infected.
Any of the closely packed guests and staff members at the Rose Garden ceremony could have gone on to transmit the virus to many others, so the White House’s decision not to investigate the cluster of infections, and pinpoint the source, has potentially devastating consequences for hundreds of people, several experts warned.
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White House Is Not Contact Tracing ‘Super-Spreader’ Rose Garden Event
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The importance of retrospective contact tracing....
This Overlooked Variable Is the Key to the Pandemic
It’s not R.
Cevik identifies “prolonged contact, poor ventilation, [a] highly infectious person, [and] crowding” as the key elements for a super-spreader event. Super-spreading can also occur indoors beyond the six-feet guideline, because SARS-CoV-2, the pathogen causing COVID-19, can travel through the air and accumulate, especially if ventilation is poor. Given that some people infect others before they show symptoms, or when they have very mild or even no symptoms, it’s not always possible to know if we are highly infectious ourselves. We don’t even know if there are more factors yet to be discovered that influence super-spreading. But we don’t need to know all the
sufficient factors that go into a super-spreading event to avoid what seems to be a
necessary condition most of the time: many people, especially in a poorly ventilated indoor setting, and especially not wearing masks. As Natalie Dean, a biostatistician at the University of Florida, told me, given the huge numbers associated with these clusters, targeting them would be very effective in getting our transmission numbers down.
Overdispersion should also inform our contact-tracing efforts. In fact, we may need to turn them upside down. Right now, many states and nations engage in what is called forward or prospective contact tracing. Once an infected person is identified, we try to find out with whom they interacted afterward so that we can warn, test, isolate, and quarantine these potential exposures. But that’s not the only way to trace contacts. And, because of overdispersion, it’s not necessarily where the most bang for the buck lies. Instead, in many cases, we should try to work
backwards to see who first infected the subject.
Because of overdispersion, most people will have been infected by someone who also infected other people, because only a small percentage of people infect many at a time, whereas most infect zero or maybe one person. As Adam Kucharski, an epidemiologist and the author of the book
The Rules of Contagion, explained to me, if we can use retrospective contact tracing to find the person who infected our patient, and
then trace the forward contacts of the infecting person, we are generally going to find
a lot more cases compared with forward-tracing contacts of the infected patient, which will merely identify
potential exposures, many of which will not happen anyway, because most transmission chains die out on their own.
The reason for backward tracing’s importance is similar to what the sociologist Scott L. Feld called
the friendship paradox: Your friends are, on average, going to have more friends than you. (Sorry!) It’s straightforward once you take the network-level view. Friendships are not distributed equally; some people have a lot of friends, and your friend circle is more likely to include those social butterflies, because how could it not? They friended you and others. And those social butterflies will drive up the average number of friends that your friends have compared with you, a regular person. (Of course, this will not hold for the social butterflies themselves, but overdispersion means that there are much fewer of them.) Similarly, the infectious person who is transmitting the disease is like the pandemic social butterfly: The average number of people they infect will be much higher than most of the population, who will transmit the disease much less frequently. Indeed, as
Kucharski and his co-authors show mathematically, overdispersion means that “forward tracing alone can, on average, identify at most the mean number of secondary infections (i.e. R)”; in contrast, “backward tracing increases this maximum number of traceable individuals by a factor of 2-3, as index cases are more likely to come from clusters than a case is to generate a cluster.”
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