COVID-19: Can We Pass This Test? (April 14, 2020)

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COVID-19 continues to change our world. Who would have thought kids would miss going to school and adults would miss going to work? What tests must we pass to get back to normal?

On March 3rd, Keep.Health first wrote about COVID-19. At that time, China, Italy, Iran and South Korea had over 1000 cases each. Epidemic clusters were spreading around the world with over 93,000 cases and 3000 deaths. 51,000 people had recovered.

Six weeks later on April 14th, 73 countries have more than 1,000 cases of which fifteen have more than 20,000. Worldwide, there are ~1.9 million cases with ~450,000 recoveries and ~120,000 deaths. The COVID-19 mortality risk has risen to ~6% driven upwards by the 12% tragedy in Italy.

The Center for Disease Control (CDC) provides these guidelines to determine if and when you should get tested for COVID-19. So far, in the United States, nearly 3 million people have been tested with ~20% being positive, ~100,000 hospitalized and ~25,000 deaths. Because of social distancing and sheltering at home, the number of positive tests plateaued in early to mid-April at around ~30,000 new infections per day and is declining. With a population over 300 million, this is about 1 in 10,000 people receiving positive test results each day. Only about 90 in every 10,000 people have been tested so far. That’s less than 0.1%. Here’s a dashboard of how many tests are being done each day. There are lengthy delays and a shortage of testing materials. Much more testing is needed.

Inexpensive, regular and widespread testing is needed to identify:

  • Newly infected people (molecular testing)
  • Those who have recovered and developed immunity (serological testing)
  • How long that immunity lasts (recurring serological testing)

Newly infected people need to be alerted rapidly so they can then avoid infecting others. In the near-term if we follow what China did, continuous testing will take the form of temperature tests for anyone leaving home, taking public transportation, arriving at work or going into stores or events. Fevers are typically Day 2 COVID-19 symptoms, so there is still risk in spreading from those who are infected but asymptomatic. Alternatively, molecular testing could follow how influenza is diagnosed today. Rapid virus protein antigen tests use a swab of the nose or throat applied to a paper strip similar to a home pregnancy test. They attempt to determine if the COVID-19 molecules are present. Unfortunately, it is unlikely these can be reliable enough for COVID-19. One possible solution is being created at At Harvard’s Wyss Institute where scientists are working on many COVID-19 projects including developing a diagnostic mask which changes color in 1-3 hours after exposure to COVID-19. This would work well but may take a while to develop at scale and may not be inexpensive enough for mass distribution. Also, like N95 masks, they may need to be replaced daily to remain effective in protecting the wearer.

To help people know when they’ve encountered someone who has been infected, governments In South Korea, China and Singapore rely on apps such as TraceTogether to track people. They also use this to verify that infected or potentially infected people remain in quarantine. In the United States, social distancing tracking sites still show too much non-essential movement in many states so we continue to have a high rate of newly infected people.

To determine those who have developed immunity, over 60 companies are pursuing serological tests to identify IgM or IgG antibodies created in response to COVID-19 antigens. Their tests must distinguish COVID-19 antibodies from other coronavirus antibodies such as those for common colds. 

Rapid serological tests produce a result in under 15 minutes from a drop of blood, but are limited in accuracy. The first FDA approved serological test (from Cellex) was tested on only 128 people. It achieved ~94% accuracy in detecting positives for immunity and 96% accuracy detecting negatives. This means ~4% of those tested would think they are immune, but wouldn’t be. They will have little way of finding out that the test was wrong other than by contracting the virus in the future at which point, they may add to the list of people believing that re-infection is possible. (The potential for re-infection is scientifically unlikely despite the South Korea study claiming 53 people were re-infected.)

For those wondering, serological testing cannot be used safely for initial COVID-19 diagnosis because there are not enough antibodies in the blood during the early days of infection. 

Some countries such as France, Germany and Italy are considering rolling out immunity passports for those who are determined to have immunity. The immunity passport grants eligibility to enter a restricted zone and/or participate in normal activity. The concept is familiar to any frequent traveler who carries a yellow fever immunization card, and to any parent who has had to document their child’s measles immunity to register for school. However, near-term, only a small percentage of the population would be eligible. Widespread use of immunity passports won’t likely happen until vaccines become available and significant operational challenges are resolved.

Of note, intentionally getting COVID-19 so that you can get an immunity passport is not a good idea. Even if you survive, COVID-19 can cause permanent damage to your lungs and heart. Of 416 hospitalized patients in China, researchers found that 19% showed signs of new heart damage. About half survived. In fact, patients with no pre-existing heart conditions who incurred heart damage during their infection were more likely to die than patients with previous heart disease but no COVID-19-induced cardiac damage.

Additionally, COVID-19 is being evaluated for its effect on testicular function. ACE2, the receptor for entry into the target cells by COVID-19, is expressed abundantly in testes, including sperm. Testing of sex-related hormones between 81 reproductive-aged men with COVID-19 infection and 100 age-matched healthy men found significant changes. The impact is unknown.

Also, serological testing studies on other coronaviruses indicate that immunity for COVID-19 may only last for 1-3 years. This is why recurring serological testing and booster shots will be necessary.

The last reason not to intentionally get infected now is that hospitals are running short on sedatives and antibiotics for those they have to intubate to put on ventilators. 

In summary, the United States needs to develop, manufacture and deploy accurate widespread tests and eventually vaccines. The faster this can be done, the faster we can return to school and work…and then hopefully no longer complain about being there!

Additional Notes of Interest

Your Reward for Reading

As your reward for reading and because we need some fun at home to get through tragic times, check out Google’s augmented reality with 3D animals. You can view lions, tigers, cheetahs, wolves, brown bears, deer, emperor penguins, horses and alligators in your environment. Here’s the full animal list. This is great fun to entertain kids and to share with your friends.

On iPhone iOS 11+  and Android 7+ phone models:

  • Type the animal’s name into Google
  • Scroll down and then press ‘View in 3D’
  • This will bring up your camera; ~30 seconds later you have the animal in your house! 
  • You can take a photo with them

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