27 Jan, 5 tweets, 2 min read
Many Qs about why it is that new #covid19 variants that are more transmissible will cause exponentially more infections (i.e. why something that is 70% more transmissible doesn't just cause 70% more infections & deaths).

A thread with an illustrative example (1/5):
Let's say that R0 (virus reproduction number) is 1.1

In the first round of infection, number of people infected = 1 (original person) + 1.1 =2.1

Next round = (2.1-1)*1.1 + 2.1 = 3.3
Third round = (3.3-2.1)*1.1 + 3.3 = 4.6

After 9 rounds, we get to 15.9.
(2/5)
Now, let's say a new variant is 70% more transmissible--say the R0 for the new strain is 1.1*1.7.

You still start out with 1. Then:

First round = (1)*1.1* 1.7 + 1 = 2.9
Second round = (2.9-1)*1.1*1.7 + 2.9 = 6.4

After 9 rounds, we get to a whopping 600 infected.
(3/5)
Screenshot of my calculations and formula here.
(4/5)
This explains why countries where the new more contagious variants have become dominant faced such extraordinary surges.

Even if the lethality remains the same (note: B117 may be more lethal), a much greater rate of infections will lead to much higher number of deaths.
(5/5)

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# More from @DrLeanaWen

9 Jan
While I applaud pres-elect @JoeBiden's commitment to speeding up vaccinations, I'm concerned about the new policy to release all available doses without guarantee of timely administration of 2nd doses for all 1st doses given.

My @PostOpinions op-ed (1/6): washingtonpost.com/opinions/2021/…
First, the bottleneck now is not supply, but the "last mile" between getting the vaccine to distribution sites & injecting it into people's arms. Speeding up this process should be the focus, or else vaccines will just sit in different freezers.

(2/6)
I'm also deeply troubled by the idea that we could be rushing first doses out without a guarantee of timely 2nd doses. Clinical trials were conducted with 2nd dose 3- or 4-weeks after the 1st. If we deviate from science, this could fuel vaccine hesitancy.

(3/6)
29 Dec 20
At the current rate of #covid19 vaccinations, it will take the U.S. 10 years to inoculate 80% of Americans.

Instead of obfuscating & deflecting responsibility, the federal government needs to take 3 urgent steps.

My @washingtonpost op-ed (1/6): washingtonpost.com/opinions/2020/…
I know ramping up a complex operation is hard. It's possible 2 million is an undercount.

What concerns me most is that officials are backtracking on their promises. It's giving me flashbacks to the testing debacle (remember "everyone who wants a test can get one")? (2/6)
So what can be done? 3 things.

1) Set up a real-time public dashboard to hold the right officials responsible and to target additional resources to where are most needed. (3/6)
10 Jul 20
In my testimony to the House Homeland Security Subcommittee today, I provide 10 actions Congress must take to reduce the unequal impact of #covid19 on Latinos, African-Americans, Native-Americans & other communities of color.

My recommendations: (1/7)
homeland.house.gov/activities/hea…
1. Target testing to minority & underserved communities. Congress must instruct FEMA to ramp up testing & set up facilities all across the country.
2. Track demographic information to ensure equitable resource allocation.
3. Hire contact tracers from minority communities. (2/7)
4. Provide free facilities for isolation & quarantine.
5. Suspend immigration enforcement for those seeking medical assistance for covid-19. Congress should prohibit ICE from accessing records of those seeking care for covid-19. (3/7)
26 Jun 20
So much wrong with @WhiteHouse presser on #covid19. We have record #s of infections in the U.S.--40,000 yesterday, and if only 1 in 10 being detected, means 400,000 people became infected. Hospitalizations are rising. Deaths will soon follow. Where is the urgency? (1/4)
They're saying testing is important. That's what public health experts have been asking for all along.

But where's the national plan for testing (& tracing + isolation)? We need at least 10X amount of testing we have now. (2/4)
In some areas, testing, tracing, isolation will not be enough: we need aggressive social distancing measures. Yes, it's individual responsibility, but public officials need to emphasize public health messaging + institute policies. Require masks. Limit indoor gatherings. (3/4)
4 Jun 20
Testifying now to U.S. House of Representatives Select Subcommittee on #Coronavirus Crisis, on how #covid19 has unmasked long-standing health disparities among African-Africans & other minorities, who now bear the greatest brunt of this pandemic coronavirus.house.gov/news/press-rel… (1/9)
The problems of structural racism & systemic inequities are huge and cannot be solved overnight. But there are concrete actions that can be taken now.

I outline four in my oral testimony. Full written testimony to be posted on @COVIDOversight coronavirus.house.gov/subcommittee-a…. (2/9)
1. The federal government must target public health resources to minority and underserved communities. This includes targeted testing with a real-time dashboard for testing & contact tracing  + providing free housing for those who need to self-isolate. (3/9)
27 May 20
The U.S. has just reached 100,000 deaths from #covid19. What have we learned? A thread of 10 lessons:
1. This is an extremely contagious respiratory illness that spreads rapidly from person-to-person. Containment is very hard.
2. But it can be done. South Korea, New Zealand, Germany & many others have been able to reduce covid-19 infections to low enough levels that they can identify and rein in new infections. It takes strong, consistent & clear national leadership.