COVID This Week
The looming question: Internal travel restrictions
1/22 This week: continued spread of Covid at a high rate in most of the US, continued shortages and delays in testing, and continued confusion about what the data show and what we need to do to control Covid.
The looming question: Internal travel restrictions
1/22 This week: continued spread of Covid at a high rate in most of the US, continued shortages and delays in testing, and continued confusion about what the data show and what we need to do to control Covid.
2/22 First, how much Covid is there? I track percent positivity as the least bad indicator. Reported cases are the tip of the iceberg: these cases reflect both how much spread there is and how much testing and reporting there is.
3/22 Although test positivity decreased slightly, from 7.7 to 7.0, it remains high in much of the country and very high in the South. But there’s a problem. Antigen tests becoming widespread and if not reported, we will lose ability to know of all positive and negative tests. 
4/22 Also, most places report proportion of tests positive. This proportion decreases with less re-testing of positives (generally not needed), & low-risk screening, even if cases don’t decrease. Proportion of patients positive is better, but harder & many places can’t do it yet.
5/22 Still, test positivity is very useful. See the gray line. Kids ages 5-17 now have the highest positivity rate of all age groups, and seniors (green line) went from highest to lowest. Age groups aren’t islands; spread in any group is a risk to all.
6/22 Incidence is misleading. Look at Alabama vs. Alaska. Alabama has nearly 3x the reported incidence of Alaska, but Alaska is testing at more than 3x the rate. The actual incidence is likely about 10x higher in Alabama. Test positivity is much more informative.
7/22 Even if accurate incidence is known, the key is how much unlinked spread there is. Singapore and other places doing a good job focus on this. If you knew that, you’d know the equivalent of how much Covid it’s raining in your community, and could protect yourself better.
8/22 For most of the US, the answer is simple: way too much Covid is spreading, uncontrolled, in the community. We must close bars, restaurants, and other indoor spaces, reduce gatherings, mask up (correctly & no valve), wash hands, clean surfaces, increase ventilation.
9/22 If we understand where Covid is spreading, we can reduce risk. Kudos to Louisiana for investigating this and reporting it openly. Of known outbreaks, food processing, bars, industry, casinos, and, yes, restaurants top 5. ldh.la.gov/index.cfm/page…
10/22 Other places that are doing a good job of sharing risk with communities include Oklahoma, Alaska, Ohio, Utah, the Southwest district of Idaho, Dallas, and the City of Los Angeles, all of which have implemented Covid alert level systems.
11/22 Some sloppy thinking about flu. With less global travel and more masks, handwashing, distancing, we may have a lot less flu. Look at this striking graph from Chile. An unexpected “health dividend” from Covid action could be less flu. But still, get a flu shot, definitely.
12/22 Nothing is more important than reducing deaths. This means not just deaths from Covid but also deaths from the disruption caused by Covid. Reported Covid deaths will reach 184K in US and 882K globally within a month. preventepidemics.org
13/22 Arizona, Florida, South Carolina, and Texas: more than twice as many excess deaths as Covid deaths. Some are undiagnosed/unreported Covid, some from disruption (especially heart attacks). Covid kills. "The death rate is a fact, all else is an inference." /econ.st/2WOS9d4
14/22 .@nytimes has an informative visualization of how many more people died than usual in each state and region of the US since the pandemic began. The total number of excess deaths in the US? At least 200,000. nyti.ms/30S7xri
15/22 What scares me most about Covid? Millions of deaths from disruption Covid causes, most in Africa. We must protect health care workers and health care systems, support communities to vaccinate against killer diseases, and continue treatment for HIV, TB, and malaria.
16/22 Meanwhile in China. They report they can now do 4.8M PCR tests/day. Schools are opening and staying open. Mask-wearing is, where appropriate, nearly universal. Last week, they had an average of 34 cases/day. That's a case rate less than 1/5,000th that of the US.
17/22 Three notable developments. Study suggests surgical masks are likely a lot better than cloth; we need to ramp up production and distribution. Immunity is complicated, with lots more to learn. Russia giving vaccine before studies done, a risky gamble. bit.ly/33YyrzX
18/22 White House considering limits on return of US citizens and permanent residents with Covid disease or exposure. Another distraction. The real issue: People from areas of US with Covid rates much higher than most countries in world to places like NY, with much lower rates.
19/22 This brings us back to incidence. Modeling is one way to estimate how hard it’s raining Covid in each community. With ~350K new infections/day in the US, that means about 2M infectious people, or about 1/165, but with a wide range. covid19-projections.com
20/22 Texas, Alabama and others have an estimated risk of infection 40X that of NY. Approximately 1 in 60 people in those states are infectious vs. about 1 in 2,500 in NY -- NY has the same level of risk of Germany.
21/22 So, you tell me, which makes more epidemiologic sense, restricting travel to NY of Americans coming from Germany, or from areas in the US that have failed to control Covid? Hint: The risk to New Yorkers is 40 times higher for the latter.
22/22 Epidemiology, not politics, should drive action to stop Covid. Australia, Canada, others limit travel within country. As differences in risk of Covid persist, pressure to reduce travel from lagging states will increase. Control Covid in your community, or please stay put.
