April 22, 2020
Earth Day
Winter returned to Seattle in the form of rain today. Not cold, just chilly and gray, but welcomed by the gardens, since this has been the driest April on record here. Jamie and I were optimistic and planted our tomatoes and padrone peppers last weekend when the sun was out. We use “walls of water” or “season extenders” that are teepee shaped tubes of water that keep the plants warm enough to get a jumpstart. If we are lucky we will be eating tomatoes by July. We always say that harvesting tomatoes in Seattle is proof of global warming. It just wasn’t possible 30 years ago.
So much news today that I can’t keep up. News of an earlier death in California shakes up the story about when SARS-Cov-2 first got to the US. Obviously it was here earlier- not completely surprising, because the person that died worked for a company that had offices in Wuhan. Worries that opening up public spaces too soon could cause more deaths now and a second, worse surge next fall.
Some other news was this story in the New York Times that compares 5 models used for predicting how the outbreak plays out over the next month. It makes sense to compare them this way to understand the varied situations. The caveat about the models is that they are all based on sticking with our social distancing model. But the good news is that deaths will be lower than the initial prediction. But there is still so much we don’t have data on yet- like how many people have already had COVID-19 and what the death rate really is. We need more testing to know.
That is why the big news in Seattle is that antibody testing for SARS-CoV-2 is being rolled out. UW is offering it now and we will have it next week. Patients are already calling asking for the test. I explained earlier that the test checks for antibodies called IgG to SARS-CoV-2, the virus that causes COVID-19. The antibodies take a couple of weeks to develop, so it is not the test to get if you think you have it right now. Our local blood bank is using the test to confirm if someone can donate their convalescent plasma to a critically ill patient.
But there are still things we don’t know. It may show if you had COVID-19, but there are both false positives and false negatives. And we don’t really know if a positive test means you are immune, meaning can you get the infection again? And if you are immune, how long will it last? We are hopeful, despite reports of patients that may have “relapsed”, but still not hopeful enough to say definitively that if an antibody test is positive that you can’t get COVID-19 again. I did read some early data from a study in Germany that shows lots of virus in the throat and sputum that started decreasing when the antibody was tested. This is a link to the abstract and you can download the PDF. The fact the virus started decreasing in these patients after they developed IgG is reassuring to me.
We have to keep in mind a few things. One is that these tests are new. The ones we will be using have been validated but only in a limited fashion, not as rigorously as usual. Things have sped up so that we have more tools. The hope is they will be accurate enough. Other antibody tests being sold have not been vetted as well, which matters. Another thing is that SARS-CoV-2 is a coronavirus which is related to one of the viruses that causes the common cold. Some of the tests may actually detect that IgG and not the SARS-CoV-2 virus and be a false positive. And that is one reason why we are not completely sure about long term immunity, because immunity to the coronavirus that causes colds does not last forever.
Our local public health department has put together this fact sheet that explains better than I can some of these concerns. This is good news overall. It will help us understand the true numbers of infections and help determine the overall death rate, but it is too early to say if it will help you know your future risks.
But the speed at how fast this knowledge and research is occurring is the hopeful thing. And to me, despite the political machinations of governments, the worldwide collaboration between researchers, physicians, Public Health Officials, and others truly makes today Earth Day.
Wash your hands!
And finally, my caveat is that this is my experience and my opinions, which are subject to change as more information is available, and not related to the organization I work for. Thanks for reading.
https://publichealthinsider.com/2020/04/21/antibody-serology-tests-what-we-know-and-dont-know/
https://www.nytimes.com/2020/04/22/us/santa-clara-county-coronavirus-death.html
https://www.washingtonpost.com/health/2020/04/22/reopening-america-states-coronavirus/
https://www.nytimes.com/interactive/2020/04/22/upshot/coronavirus-models.html?
https://www.nytimes.com/2020/04/21/magazine/coronavirus-scientific-journals-research.html