Thursday, May 14, 2020

A few weeks ago I described a new Coronavirus antigen test as a “game changer.” But day after day the game looked pretty much the same. Today, however, there is a new headline from the UK: “Coronavirus: ‘Exciting ‘ results of antibody tests show ‘100% accuracy’ in potential breakthrough,” Game changer or not, this new antibody test, developed by the Swiss company Roche and the first one approved for use in the UK, comes at a time of rapidly increasing antibody testing. It’s time to take a closer look at antibodies.

Antibody — Antigen: Think of them as a lock and key

An antibody is an immunoglobulin which is a type of protein produced by your immune system. Antibodies bind to specific targets or antigens–in this case specific sites on the surface of the virus which it can then neutralize, rendering it harmless. This response to coronavirus happens in two phases: first you produce IgM (immunoglobulin M) and later comes IgG (immunoglobulin G), which lasts much longer, measured in months or years.

We don’t know at this point just how long the antibody production lasts and how much protection it may give against getting COVID-19 a second time. After all, COVID-19 has only been around in humans for a few months. As a former lab tech, I would cautiously state that a positive test means antibodies were detected. Assuming the test was specific for the COVID-19 antibody, positive means you have had a past or recent infection with COVID-19, even if you didn’t feel sick. A negative test, on the other hand, means no antibodies were detected. Maybe it’s too soon after your exposure to the virus. Maybe your immune system never encountered COVID-19. Maybe it did, but for some reason you were not able to make antibodies.

What about the claim of “100 percent accuracy”? That’s a short way of saying that if the test is positive you actually have been exposed to and produced antibody to SARS-CoV-2, the coronavirus which causes COVID-19. In other words, the test does not react to similar antibodies produced by other coronaviruses such as the common cold and SARS. When Roche claims 100 per cent specificity for its test, they mean that it can be relied on to track COVID-19 without false leads.

Because that is what the antibody test is used for. We hope to learn how widespread the infection is, where and how fast it is spreading, who is most likely to get it, how widespread is infection without symptoms, are the antibodies protective and how long do they last. But antibody testing is not only critical for reopening. It’s also vital to the development of vaccines and treatments.

Tracking and testing are usually public/private collaborative efforts and they are taking place all over the world. The CDC is involved with a number of large and small surveys in partnership with public institutions and private companies. Genalyte is working with San Diego Blood Bank with trials of convalescent plasma as a therapeutic treatment for COVID-19. Roche and the NIH (National Institutes of Health) are working in a public-private partnership called Accelerating COVID-19 Therapeutic Interventions and Vaccines or ACTIV. (https://www.roche.com/strongertogether/nih-partnership.htm).

So is the first antibody test to be approved in the UK a “game changer”? At least three people in the course of today’s article called it that: Prime Minister Boris Johnson, TV doctor Dawn Harper, and Junior Health Minister Edward Argar. I hope they’re right.

Today’s Notable Headlines

“Coronavirus: ‘Exciting’ results of antibody test show ‘100% accuracy’ in potential breakthrough,” Andy Weeks, Yahoo News UK, May 13, 2020. https://news.yahoo.com/coronavirus-antibody-test-065939982.html

“Coronavirus: UK government in talks with Roche about ‘highly specific’ antibody tests,” Edmund Heaphy, Finance and news reporter, Yahoo Finance UK, May 14, 2020.  https://www.yahoo.com/finance/news/coronavirus-uk-government-in-talks-with-roche-about-highly-specific-antibody-tests-083543704.html

“Genalyte and San Diego Blood Bank team up to fight COVID-19,” CBS8, May 13, 2020. https://www.cbs8.com/article/news/local/genalyte-and-san-diego-blood-bank-team-up-to-fight-covid-19/509-0c7051af-8b19-49b2-adbb-29f319d47652?fbclid=IwAR39-GwNOysENkh1Pip1_qgAPU-5DquTvxCG7tfrZjvA3UdMpGQ9P29UQIc

“ Coronavirus: Which countries have antibody tests and how accurate are they?” Ciara Giordano, The Independent, May 14, 2020. https://news.yahoo.com/coronavirus-countries-antibody-tests-accurate-124356361.html

“Antibody tests could be key to reopening the country. Here’s how they work,” USA Today, April 20,2020. https://www.usatoday.com/in-depth/news/2020/04/20/coronavirus-testing-how-antibody-tests-work-and-why-needed/2988440001/

Additional Sources:

Full technical explanation of specificity and sensitivity on https://en.wikipedia.org/wiki/Sensitivity_and_specificity

CDC on testing for COVID-19: https://www.cdc.gov/coronavirus/2019-ncov/symptoms-testing/testing.html

Guidance on Interpreting COVID-19 Test Results https://www.whitehouse.gov/wp-content/uploads/2020/05/Testing-Guidance.pdf

“COVI-19 and the mysterious world of antibodies,” Timothy Tellinghuisen, April 28, 2020. https://www.roche.com/strongertogether/covid-19-antibodies-immunity.htm

Public-private partnerships, such as the NIH and Roche, called Accelerating  COVID-19 Therapeutic Interventions and Vaccines or ACTIV. https://www.roche.com/strongertogether/nih-partnership.htm

Genalyte antibody test information sheet: https://www.genalyte.com/wp-content/uploads/2020/04/SARS-CoV-2-Product-Sheet-4_20.pdf

Why am I doing this?

The coronavirus pandemic will be indelibly written on our memories just as the Great Depression or the Battle of Britain left their mark on past generations. It is my intention to journal the events of these days from three perspectives: as a retired medical technologist, a historian (Ph.D., 2014), and an ordinary person living through an extraordinary crisis.

You are on History’s Edge.

2 thoughts on “Pandemic Day 65: Antibody Tests

  1. Pingback: Pandemic 155: Monoclonal Antibodies | History's Edge

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