We are racing to vaccinate the US and worldwide population for COVID19 for many reasons: to prevent deaths, limit emergence of dangerous strains, and achieve herd immunity. Let’s talk about the spread of vaccination behavior. 1/
We can think of some of our behavioral responses to an epidemic like #COVID19 (e.g., mask wearing, getting vaccinated) as a kind of *social contagion*, spreading from person to person, which in turn addresses the *biological contagion*. 2/
In 2017, we published a reconstruction of the temporal dynamics of the spread of vaccination behavior and of the H1N1 influenza virus during the 2009 pandemic in a circumscribed social network of @harvard students. nature.com/articles/srep4… via @SciReports @nature 3/
We could trace out how *both* the virus and vaccination behavior spread across social ties across time, day by day over four months, as the 2009 H1N1 epidemic peaked. 4/
Here is how the H1N1 virus spread over a period of three months in 2009. Infected individuals are colored red, friends of infected individuals are colored yellow, and node size is proportional to the number of friends infected. 5/
A video of the spread of the H1N1 virus from person to person in a defined social network during the 2009 pandemic is here: doi.org/10.1371/journa… via @PLOSONE 6/
People are more likely to get the flu if their friends get the flu. And people are also more likely to manifest behaviors (e.g., vaccination, masking) if their friends do so. 7/
Furthermore, each of those phenomena – the virus and behavior – affects the spread of the *other* phenomenon. 8/
We can think of these two contagions – one biological and one social – as a kind of *dueling contagion*. Each affects the other. This is the key idea behind #duelingcontagions. Which contagion wins out, and under what circumstances? 9/
Using data collected during the 2009 H1N1 pandemic that includes information about vaccination, flu, and the detailed structure of face-to-face social networks, we showed that well-connected individuals are more likely to get vaccinated. 10/
Using data collected during the 2009 H1N1 pandemic, we also showed that people who are exposed to friends who get vaccinated or are exposed to friends who get the flu are then more likely to get vaccinated. 11/
Our dueling contagion model suggests that the rate of vaccination contagion may be even *more* important than the biological contagion in determining the overall course of the epidemic. 12/
This figure shows the cumulative incidence of vaccinated individuals and of infected ones starting September 1, 2009 during the H1N1 pandemic. Levels of vaccination and of disease prevalence increase from zero and reach a plateau almost at the same time. 13/
This figure displays snapshots of the social network at time point t = 10, 40, 120 days. Size of nodes is proportional to network degree, and color of nodes represents their health status: RED infected, BLUE vaccinated, and GRAY are unvaccinated and healthy. 14/
The network snapshots provide a microscopic, spatio-temporal view of the dueling contagions on the friendship network, showing that the relatively fast spread of vaccination behavior impedes the spread of the germ and the development of a severe epidemic. NB @vivek_murthy 15/
Real world and online networks that make it easier to actually see when friends have been vaccinated (personalized vaccination campaigns) and when they get the flu (personalized flu warnings) could have a large impact on reducing the severity of epidemics. 16/
A similar formulation of the idea of #duelingcontagions was advanced by @Alison_Galvani and @cbauch1 in @ScienceMagazine in 2013: science.sciencemag.org/content/342/61… 17/
An old thread about the spread of the flu virus in this social network, along with other links and information, is here: These ideas also find use in our HUNALA app useful for assessing personal risk of COVID19 @HunalaApp 18/
An old thread about practical issues in actually getting a large fraction of the population vaccinated (inventing, manufacturing, distributing, and administering the COVID19 vaccine) is here: 19/
If you are interested in how social behavior changes in times of plague, and how this change in behavior affect the spread of pathogens more generally, there is more in #ApollosArrow: amazon.com/Apollos-Arrow-… 20/

• • •

Missing some Tweet in this thread? You can try to force a refresh

Keep Current with Nicholas A. Christakis

Nicholas A. Christakis Profile picture

Stay in touch and get notified when new unrolls are available from this author!

Read all threads

This Thread may be Removed Anytime!


Twitter may remove this content at anytime! Save it as PDF for later use!

Try unrolling a thread yourself!

how to unroll video
  1. Follow @ThreadReaderApp to mention us!

  2. From a Twitter thread mention us with a keyword "unroll"
@threadreaderapp unroll

Practice here first or read more on our help page!

More from @NAChristakis

8 Jan
Twitter permanently suspends Donald Trump account. I understood why they resisted until now, despite his prior violations, given the fact that he was president, but consistency is so important to values and public policy. Still, better late than never. nbcnews.com/tech/tech-news…
My key issue here is consistency. If others had to abide Twitter rules, I never liked that politicians, incl Trump, didn’t.

Distinctly, I also feel that monopolistic companies (eg, public square ones — see classic case of malls) might need to be regulated like public utilities.
This is a good example of why consistency is important and also so difficult. Will Twitter now delete any other accounts violating its rules?

To be clear, directly fomenting violence (and insurrection) is a special kind of speech.
Read 11 tweets
4 Jan
I had assumed that the #DisruptTexts movement was organic. But I recently discovered disrupttexts.org, and I think that, in addition to publishers springing into action to meet market demand, they may possibly be playing a role in fostering abandonment of classics. 1/
Because, there is perhaps much less money to be made selling classics. 2/
I need to be VERY clear that I am wholly in favor of *expanding* the cannon and adding relevant, engaging texts for students in middle school, high school, and (of course) college. Students can and should read Baldwin, Marquez, Tan, Walker, Morrison, Malcolm X, and on and on. 3/
Read 11 tweets
6 Dec 20
People have been talking about the Joe Rogan Experience #JRE podcast @joerogan, which I am happy to have been on twice. I think Joe is a first-rate interviewer, a great and genuinely curious conversationalist. And the breadth of the guests is astonishing, and to his credit. 1/
The breadth of his *listeners* and his reach are also astonishing and to his credit.

Here is a short personal illustration: After my first appearance, in March of 2019, I left my apartment in New Haven @yale the next morning to walk to work. 2/
The African-American doorman in my building, a man in his 50's with whom I have had countless warm conversations about many topics, told me he had heard me the preceding day and that he really enjoyed our conversation and "learned so much." 3/
Read 10 tweets
25 Nov 20
I’d need to better understand the motivations for this bill. And I’m not opposed per se. I find “period poverty” disconcerting.

But if the bill is based on righting an innate gender inequity, will the parliament also mandate equal life insurance premiums for men and women?
And pads and tampons can be crucial for young women in many settings, as in this classic study by Esther Duflo showing that providing menstrual products enhanced school attendance (and much else) in poor women in Africa. nytimes.com/2007/11/12/giv…
I misremembered some details. Here are some other studies: cgeg.sipa.columbia.edu/sites/default/… indicated that providing sanitary pads reduces absenteeism by 5.4 percentage points. But bmjopen.bmj.com/content/6/11/e… shows no effect. NB @jt_kerwin
Read 7 tweets
19 Nov 20
Actually, this could be a serious problem for COVID19 vaccine trials. I would have to look at the specific details of outcome ascertainment of the trials, but if participants have used testing to unblind themselves, this could affect their behavior and also measured outcomes. 1/
And here is a mention of a participant in the placebo arm who may have known their status (via @mjaeckel). 2/
Whether such unblinding has increased or decreased the estimated efficacy of the COVID-19 vaccine being assessed depends sensitively on a host of factors. 3/
Read 4 tweets
30 Oct 20
I am ashamed of how bad our great nation has done in combatting COVID19. When China locked down its country, on January 24, 2020, we should have used that time to better prepare. #ApollosArrowChat 1/
On January 24, 2020, China essentially put 930 million people under home confinement. Along with Chinese colleagues, we showed this in this @nature paper: nature.com/articles/s4158… Movement in the country stopped. 2/
In essence, China felt that SARS-CoV-2 was so powerful that it had to detonate a "social nuclear weapon," as I argue in #APOLLOSARROW (for some details, see this thread from March 9: ) 3/
Read 5 tweets

Did Thread Reader help you today?

Support us! We are indie developers!

This site is made by just two indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member ($3/month or $30/year) and get exclusive features!

Become Premium

Too expensive? Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal Become our Patreon

Thank you for your support!

Follow Us on Twitter!