Serological testing in Germany shows resistance to coronavirus SARS-CoV-2 at 14 percent

First preliminary results from widespread IgA/IgG SARS-CoV-2 resistance antibody testing in Heinsberg Germany

Being an active research scientist or having a life science research background during a once-in-a-lifetime worldwide epidemic is a remarkable thing. Whether reading pre-prints on MedRxiv or looking into the latest news of the day or reading interesting links from a variety of sources, having dozens of tabs open (and bringing your browser and computer to a crawl) is an endless feast of real-time information.

If you were curious how the pandemic has affected media consumption by generation, well here’s a handy visualization. Online press receives a healthy bump; what is it about Gen Z and Millennials about their consumption of online video, up 51% and 44% respectively, topping the increase of all media sources?

Anyway I last wrote about Cellex US having FDA Emergency Use Authorization approval for detection of protective antibodies (in this case IgG/IgM) against the causative virus for COVID-19 disease, which goes by the scientific name of SARS-CoV-2. It is notable the World Health Organization has decided not to use the scientific name, likely to not overly alarm people in the early days of the pandemic. Nonetheless I use the scientific name to be specific, there are some four coronaviruses that cause the ‘common cold’ and three other coronaviruses that cause nasty diseases (SARS ‘classic’ from 2003, MERS in 2012 and now SARS-CoV-2).

In Germany, a small town near the Netherlands border called Gangelt in the larger area called Heinsberg has a festival marking the beginning of Lent called Karneval. This town of Gangelt (about 12,000 residents) has been called ‘Germany’s Wuhan’ as it has had the largest number of infections and deaths in the country; Heinsberg (the larger principality with about 42,000 residents) as of this writing (10 April) has 1,521 cases and 45 deaths.

On 31 March 2020 it was announced they would test 1000 residents that were representative of the population, with the goal of determining at greater detail how the SARS-CoV-2 coronavirus spreads. Dr. Hendrik Streeck a Bonn virologist said at that time

If there are ways of preventing the illness from spreading in our environment, we want to know what they are, with the goal of finding out how we can freely move about in the environment together.

Dr. Hendrick Streeck, in The Guardian on 31 March 2020

It is surmised through active research across countries worldwide that the coronavirus is not spread through casual contact, such as grocery shopping or sitting next to some random people in public transit, but close social interaction such as hugging, singing, laughing and social kissing. (In Rhineland Germany they greet each other with a Bützchen, or kiss on the cheek.)

On 15 February 2020, a group of about 350 gathering for the Karneval listened to live music, mingled with food and drink, heard the town leaders and generally socialized for a total of four hours. 7 individuals, all attending that event, later tested positive, among the first of all cases in Germany.

Of the 1,000 volunteers who submitted for both rRT-PCR testing (via throat swab for active virus infection) and antibody testing for resistance to SARS-CoV-2 (via blood draw to test for anti-SARS-CoV-2 antibodies, specifically IgA and IgG), the results of the first 500 samples were released yesterday.

In the report (link to the PDF in German is here, the page this PDF comes from is located here) are some surprising, and very interesting, results: about 2% have tested positive for the virus via PCR testing, and 14% have tested positive for antibodies against the disease. Originally given the population size and infected rate, the researchers were expecting a smaller number of IgA/IgG-positive samples (perhaps 5%). In other words, one in seven have been infected and have recovered with antibodies against the virus, and can be considered ‘immune’ from being infected again (although that is also being actively studied).

This preliminary data has large (dare I say huge) implications for public health policy, as questions are currently being raised as to how the economies and society of many nations (and literally trillions of dollars of economic activity) will restart again.

From a translation of the German PDF, they claim a >99% specificity; will have to await the publication of the results to find out the details. (Friendly reminder, specificity is the ‘true negative’ rate, thus 1-specificity is the ‘false positive’ rate or <1%.)

The larger implication of this 14% number is the calculation of the death rate, known as a the ‘Case Fatality Ratio’ or CFR. If the denominator is much larger (i.e. many individuals having been infected and recovered from the virus) the CFR is much lower. Here the German virologists estimate a CFR of 0.37%, compared to the ‘official’ CFR of about 2% for Germany.

As a point of reference, the CFR for the United States is about 3.6%.

Many studies of this type are going on right now in the US; Stanford University recently announced serology testing (first among healthcare workers and this week more widely to the general population) and is ongoing in New York City although not to the wider population yet.

Accurate, and widespread serological testing is something to keep on the lookout for, as it will indicate who can be ‘certified’ to be virus-resistant. Antibody testing will be a vital tool in getting past this pandemic, along with a vaccine, and getting back to something or a normal life.

Update April 12, 2020:

Thanks to a good friend, I discovered a publication (Okba et al on the pre-print server MedRxiv.org) now up on the CDC website located here, with the details on the antigen used for their Eliza test with useful clinical-sample data. Inexplicably the CDC journal Emerging Infectious Diseases does not have this article as a tidy PDF.