Tag Archives: Coronavirus

Tale of a fast, accurate home COVID test

My son works at a company called Homodeus. It’s part of 4Catalyzer, an umbrella of seven medical biotechnology companies with a staff of 300 scientists and engineers. One of the Homodeus products, still waiting FDA guidance is a COVID-19, RNA self-tester called Homodeus Detect. It tests for COVID RNA directly, not for antibodies, with tests are much faster than hospital tests, taking 45 minutes, but more complex than the unreliable test strips. So far, the Detect tests have shown no false positives or false negatives. That would suggest 100% reliable, except but there are a fair number of invalid tests. The invalid tests are lares due to the complexity, and also to the fact that you are testing snot, essentially. There is no blood-taking involved, unlike with the test strips, but  just a nasal swab, and the cost is moderate, about $35 per test. However you have to do some lab work. After you swab your nose, you put the swab in a heated liquid bath where chemicals break up the snot and dissolve the shells on any viruses or pollen present. After 30 minutes, you pass the liquid onto a detector strip that contains a conjugate protein that binds to SARS-CoV-2 RNA. Your answer appears 15 minutes later as one of three lines: one for positive, one for negative, or one indicating an invalid test. Invalid tests show up more often than they like, about half the time, especially when the test is done by amateurs. 

Getting an invalid test result is a downside of the current product, but I don’t think it should prevent sales. You get better at doing the test, and speed and lack of false positives and negatives is a bigger plus. It seems worthwhile to fast-track offer this test for doctors offices and hospital admissions, at least. I’d also like to see it used for airplane boarding and interstate travel, so that a person traveling might avoid the two week quarantine that many states impose. I’d certainly pay $200 or more to avoid a two-week quarantine, and if I have to do a second or third test, I’d do that too. 

At least some people realize it’s a big advantage to know if you are currently infections.

Because this test measures virus RNA, and not antibodies, it indicates infection virtually as soon as you’re infected. That’s a benefit for those wishing to fly, or to meet with people, an advantage that is not lost on Elon Musk at least (see tweet). The test also shows negative as soon as the virus is gone, and that’s big. In recent months the FDA has fast-track approved an antibody indicating test from Abbott Labs, but that test has many false readings and only indicates infection several days afterward, and it does not indicate when you are no longer infectious. 

The FDA has not offered to fast track this test, or any other like it for approval. They have not even indicated what sort of reporting and privacy requirements they want, so things sit in limbo, both for Homodeus, and for competing companies. Here is a story in USA today: https://www.usatoday.com/story/news/2020/07/29/fda-opens-door-rapid-home-covid-19-tests/5536528002. One big issue that the FDA is contact tracing. The FDA would like to be able to trace all the contacts of anyone who tests positive, while maintaining privacy as demanded by the 4th Amendment.

One way around the 4th amendment concerns would be to require anyone who uses the test to sign a waiver allowing the government to trace their contacts. Alternately there could be a block-chain enabled app that would come with the test. An app coms already providing a timer for when to move to the next step, and it includes a machine-vision system to help analyze dim lines on the indicator. Perhaps the FDA would accept block chain as a way to allow full reporting while maintaining privacy The FDA has yet to provide guidance on what they want, though. Without guidance or fast-track approval, things sit in limbo. Here is a scathing legal analysis from the Yale Law Journal.

You can get a free test, but have to do it at Homodeus headquarters in Guilford, Connecticut. It’s free, and results appears in about 45 minutes.. Homodeus has been manufacturing the test in quantity; if you are interested, use the following link to sign up: https://www.homodeusinc.com/research. Healthcare providers are particularly welcome.

The Homodeus detect test kit. Picture from this article in the New Haven Register.

Why did the FDA fast-track approve Abott’s antigen/ antibody test. Maybe because the tests rethought to not lead to lower mask use. Alternately, Abott has more political pull. You can read the FDA’s explanation here. In my biassed opinion the Homodeus product is good enough to fast track especially for hospitals and healthcare providers. It could save lives while allowing the economy to reopen.

Robert Buxbaum, November 15, 2020 (with massive help from Aaron M. Buxbaum)

COVID-19 is worse than SARS, especially for China.

The corona virus, COVID-19 is already a lot worse than SARS, and it’s likely to get even worse. As of today, there are 78,993 known cases and 2,444 deaths. By comparison, from the first appearance of SARS about December 1 2002, there have been a total of 8439 cases and 813 deaths. It seems the first COVID-19 patient was also about December 1, but the COVID-19 infection moved much faster. Both are viral infections, but it seems the COVID virus is infectious for more days, including days when the patient is asymptomatic. Quarantine is being used to stop COVID-19; it was successful with SARS. As shown below, by July 2003 SARS had stopped, essentially. I don’t think COVID-19 will stop so easily.

The process of SARS, worldwide; a dramatic rise and it’s over by July 2003. Source: Int J Health Geogr. 2004; 3: 2. Published online 2004 Jan 28. doi: 10.1186/1476-072X-3-2.

We see that COVID-19 started in November, like SARS, but we already have 10 times more cases than the SARS total, and 150 times more than we had at this time during the SARS epidemic. If the disease stops in July, as with SARS, we should expect to see about a total of 150 times the current number of cases: about 12 million cases by July 2020. Assuming a death rate of 2.5%, that suggests 1/4 million dead. This is a best case scenario, and it’s not good. It’s about as bad as the Hong Kong flu pandemic of 1968-69, a pandemic that killed 60,000 approximately in the US, and which remains with us, somewhat today. By the summer of 69, the spreading rate R° (R-naught) fell below 1 for and the disease began to die out, a process I discussed previously regarding measles and the atom bomb, but the disease re-emerged, less infectious the next winter and the next. A good quarantine is essential to make this best option happen, but I don’t believe the Chinese have a good-enough quarantine.

Several things suggest that the Chinese will not be able to stop this disease, and thus that the spread of COVID-19 will be worse than that of the HK flu and much worse than SARS. For one, both those disease centered in Hong Kong, a free, modern country, with resources to spend, and a willingness to trust its citizens. In fighting SARS, HK passed out germ masks — as many as anyone needed, and posted maps of infection showing places where you can go safely and where you should only go with caution. China is a closed, autocratic country, and it has not treated quarantine this way. Little information is available, and there are not enough masks. The few good masks in China go to the police. Health workers are dying. China has rounded up anyone who talks about the disease, or who they think may have the disease. These infected people are locked up with the uninfected in giant dorms, see below. In rooms like this, most of the uninfected will become infected. And, since the disease is deadly, many people try to hide their exposure to avoid being rounded up. In over 80% of COVID cases the symptoms are mild, and somewhat over 1% are asymptomatic, so a lot of people will be able to hide. The more people do this, the poorer the chance that the quarantine will work. Given this, I believe that over 10% of Hubei province is already infected, some 1.5 million people, not the 79,000 that China reports.

Wuhan quarantine “living room”. It’s guaranteed to spread the disease as much as it protects the neighbors.

Also making me think that quarantine will not work as well here as with SARS, there is a big difference in R°, the transmission rate. SARS infected some 2000 people over the first 120 days, Dec. 1 to April 1. Assuming a typical infection time of 15 days, that’s 8 cycles. We calculate R° for this stage as the 8th root of 2000, 8√2000 = 2.58. This is, more or less the number in the literature, and it is not that far above 1. To be successful, the SARS quarantine had to reduce the person’s contacts by a factor of 3. With COVID-19, it’s clear that the transmission rate is higher. Assuming the first case was December 1, we see that there were 73,437 cases in only 80. R° is calculated as the 5 1/3 root of 73,437. Based on this, R° = 8.17. It will take a far higher level of quarantine to decrease R° below 1. The only good news here is that COVID-19 appears to be less deadly than SARS. Based on Chinese numbers the death rate appears to be about 2000/73,437, or about 3%, varying with age (see table), but these numbers are overly high. I believe there are a lot more cases. Meanwhile the death rate for SARS was over 9%. For most people infected with COVID-19, the symptoms are mild, like a cold; for another 18% it’s like the flu. A better estimate for the death rate of COVID-19 is 0.5-1%, less deadly than the Spanish flu of 1918. The death rate on the Diamond Princess was 3/600 = 0.5%, with 24% infected.

The elderly are particularly vulnerable. It’s not clear why.

Backing up my value of R°, consider the case of the first Briton to contact the disease. As reported by CNN, he got it at conference in Singapore in late January. He left the conference, asymptomatic on January 24, and spent the next 4 days at a French ski resort where he infected one person, a child. On January 28, he flew to England where he infected 8 more before checking himself into a hospital with mild symptoms. That’s nine people infected over 3 weeks. We can expect that schools, factories, and prisons will be even more hospitable to transmission since everyone sits together and eats together. As a worst case extrapolation, assume that 20% of the world population gets this disease. That’s 1.5 billion people including 70 million Americans. A 1% death rate suggests we’ll see 700,000 US deaths, and 15 million world-wide this year. That’s almost as bad as the Spanish flu of 1918. I don’t think things will be that bad, but it might be. The again, it could be worse.

If COVID-19 follows the 1918 flu model, the disease will go into semi-remission in the summer, and will re-emerge in the fall to kill another few hundred thousand Americans in the next fall and winter, and the next after that. Woodrow Wilson got the Spanish Flu in the fall of 1918, after it had passed through much of the US, and it nearly killed him. COVID-19 could continue to rampage every year until a sufficient fraction of the population is immune or a vaccine is developed. In this scenario, quarantine will have no long-term effect. My sense is that quarantine and vaccine will work enough in the US to reduce the effect of COVID-19 to that of the Hong Kong flu (1968), so that the death rate will be only 0.1 – 0.2%. In this scenario, the one I think most likely, the US will experience some 100,000 deaths, that is 0.15% of 20% of the population, mostly among the elderly. Without good quarantine or vaccines, China will lose at least 1% of 20% = about 3 million people. In terms of economics, I expect a slowdown in the US and a major problem in China, North Korea, and related closed societies.

Robert Buxbaum, February 18, 2020. (Updated, Feb. 23, I raised the US death totals, and lowered the totals for China).