What does the COVID-19 antibody test result mean for me?

Executive summary

  • Your test results could be impacted by the time between when you were infected and get the test
  • You could get a positive result for other reasons besides COVID-19

I spent the beginning of my career looking at research studies for healthcare interventions, including pharmaceuticals, diagnostics and devices. However, I have never been close to requiring the information for a personal decision. The COVID-19 pandemic has made this decision close for the mass, so I decided to take a look into the types of tests that one could get in New York City. The New York City website talks about the antibody test, but it mostly focused on providing the public information on where to get it and open times. The New York State website has information on antigen, antibody and molecular testing.

I read the FDA emergency use authorization for the New York State antibody test they developed and found the following notes interesting:

  • Interpretation of results. On the fourth page, there is a table that shows what values were used to translate to categorical results of negative, indeterminate or positive.
  • Cross-reactivity. Although there is only one on page 4-5, the West Nile virus sample came up positive and three others were indeterminate with the test.
  • Clinical performance. On page six, there is a table showing the sensitivity increasing from 17.9% to 79.3% as the days from onset ranges increased (from less than 7 to greater than 20 days – there are five ranges). The results were from over six clinical studies totaling 753 subjects.
  • Limitation. There could be false results for patients taking biotin supplements.

Based on these notes, if I got the antibody test I would like to know my value before the categorical result (to know if I’m borderline) and contextualize the test to when I may have been exposed (if I got a negative result but was potentially exposed less than 20 days ago I may question the result). If I’m also positive, I would consider if I could possibly have the West Nile virus and check if I have biotin in anything I take.

Does the COVID-19 vaccine protect against all variants?

Executive Summary:

  • There is evidence that the vaccine is effective against some variants
  • It is uncertain whether the vaccine will be effective against future variants, in which case they will need to be updated

Whether you’re considering the COVID-19 vaccine or not, you may be wondering whether the vaccine protects against new variants being discovered. Although I’m public health professional, I didn’t stay up-to-date with the latest scientific research, because I knew that there is nothing safer than preventive measures: self-quarantining first and foremost; and physical distancing and wearing a mask when outside and in public spaces. As we launched cshell health, we realized that we needed to fundamentally address health literacy in the context of the present: COVID-19 vaccine and variants. So the first thing I did was go to the global authority source, the World Health Organization (WHO) to see what they had to say on variants (published December 31th 2020 and visited on January 21st 2021).

I discovered that in June 2020, the variant that was spreading globally was not the original strain identified in Wuhan, China. Furthermore, additional strains were found in Denmark and the United Kingdom in August/September and end of the year in 2020, respectively. In December 2020, a new variant in South Africa was spreading that was different from an earlier variant. This new variant showed that it was more likely to spread but there was no evidence at the time of worse outcomes.

WHO mentioned four factors in characterizing new variants:

  • is it more contagious?
  • is there a higher likelihood of mortality and morbidity?
  • how likely is reinfection?
  • how do antibodies respond to new variants?

The WHO risk assessment is that, all else equal, if new variants are more contagious, then that could lead to more deaths and hospitalizations.

I also checked what the Center for Disease Control and Prevention had to say on new variants (visited on January 21st 2021 and page last updated January 15th 2021). They have a section on what they do not know, including how new variants spread, the nature of the disease, and what this means for vaccines and therapies.

From what I can tell now, there is no robust evidence on how new variants would respond to the current vaccine. I found an article from CNN on a study suggesting how the vaccine protects against new variants (published January 20th 2021 and visited on January 21st 2021). I read the pre-published study cited, which was published January 19th 2021 by researchers from The Rockefeller University, California Institute of Technology, National Institutes of Health (and its Clinical Center) and Howard Hughes Medical Center. These institutions are reputable in medical science, technology and clinical practice. I noticed that the sample size was small of only 20 volunteers (of which 16 were Caucasian, 8 were females, 14 received the Moderna vaccine) in the report and that activity against some variants have been reduced by “a small but significant margin”. In the Discussion section, they suggest on-going vaccines update and immune monitoring to address viral evolution.

As I was writing this, Dr. Fauci returned to the media spotlight. What the New York Times summarized was aligned with what I found: vaccine may be effective for new variants for now but may need to be updated for mutations. I would say that he is good with not causing any unnecessary public alarm and focusing on when a positive outcome would be due if we followed the necessary public health steps, specifically vaccination rates to reduce the spread, mutation and pressure on health systems.