FAQ

If you are participating in one of the C4R cohorts, please contact the cohort directly.

Unfortunately, if you are not already participating in one of the cohort studies, it is not possible to enroll in C4R directly at this time.

If you have tested positive for COVID-19, we encourage you to contact your cohort directly to share this information. The cohort may ask you for some additional information at that time.

Still, please remember that the cohort studies and C4R are research studies. If you need medical attention for any reason, including COVID-19, you should contact a doctor or call 911.

C4R is using a “dried blood spot” to measure antibodies against SARS-CoV-2, the virus that causes COVID-19. We are asking participants to prick a finger and to drip a small amount of blood onto a special card. The card stores the dried blood in such a way that you can use it for antibody tests. This approach has been used safely for many decades and is even used in newborn babies for certain newborn screening programs.

Please check out this video on how to do the dried blood spot for C4R. Please reach out to your cohort if you have any questions or concerns.

We actually don’t need very much blood at all – just one 3mm drop is enough for our test. If you got this much, it’s a success! If not, please just contact your cohort for some more support. We really appreciate your effort.

If you received a result saying that antibodies were detected on your dried blood spot for C4R (a “positive” test), this means you may have had antibodies from an infection with the virus that causes COVID-19. It could also indicate that you have been vaccinated for COVID-19. Rarely, antibodies from a different type of coronavirus can lead to a positive result, even though you might not have been exposed to SARS-CoV-2 (a “false positive”). Please note that this does not necessarily mean that you are protected from COVID-19 in the future. It also does not mean that you have the virus now or might infect other people.

If you received a result saying that antibodies were not detected on your dried blood spot for C4R (a “negative” test), this tells that you did not have a detectable level of antibodies at the time you gave us your blood sample, although past exposure is still possible. Antibodies can take several weeks to develop and then antibodies decrease over time, eventually reaching a level so low that they might not be detectable.

We actually don’t need very much blood at all. The pre-printed circle on your DBS card is about half an inch in diameter – the goal is to try and fill the size of the printed circle. It doesn’t have to be exactly within the line or completely filled, but it is important that the blood soaks through to the other side of the filter paper.   

Here’s a picture of what a perfect DBS looks like:

This one isn’t quite as perfect, but it still works for our study:

Here’s an example of a dried blood spot that we won’t be able to test, since the blood didn’t soak through the paper:

If you have questions, or if you are having difficulty, please just contact your cohort for some more support. We really appreciate your effort.

We strongly encourage you to be vaccinated. Under no circumstances do we want the research study to delay or alter your vaccination plans. The dried blood spot provides important information for C4R whether you are pre-vaccination, between vaccinations, or fully vaccinated.

As a participant, you will not receive information on whether your antibodies, if present, are likely to be due to natural infection and/or vaccination. There are rules governing the types of information we can share with participants, and therefore we will only be able to tell you if you do or do not have evidence of antibodies to SARS-CoV-2 in your bloodspot.

Nonetheless, C4R will be able study whether your blood spot has antibodies to the “Spike” or “S” protein and/or to the “Nucleocapsid” or “N” protein as part of our research. This helps us understand whether your antibodies are from natural infection or vaccination. When you are infected with SARS-CoV-2, your body is likely to make antibodies to both S and N proteins. By contrast, the vaccine will only train your immune system to make antibodies to the S protein.

So, based on information regarding S and N antibodies, C4R researchers will be able to make the following interpretations:

• If you have antibodies to both parts of the virus (S and N), there is clear evidence of a former or current infection.
• If you have antibodies only to the N part, there is also clear evidence of a former or current infection.
• If you have antibodies to just the S part, this might be evidence of a former or current infection, but might also come from being vaccinated, since the vaccines use the S part of the virus to stimulate antibodies.
• If you do not have antibodies to either part of the virus, the test result could mean several different things:
  • You have never been infected
  • You were infected, but the infection was so long ago (usually >6-8 months ago) that the antibodies have left your blood
  • You were infected or vaccinated within the past few weeks, and you have not yet built enough antibodies to be detectable with our tests

Again, unfortunately we will not be able to share these details on S and N antibodies with you directly, but it will greatly contribute to our scientific investigations.

As you know, our understanding of COVID-19 continues to increase, thanks in large part to the commitment of study participants worldwide.

If you want to stay up-to-date on the latest in COVID-19, we know that there are a lot of resources. We are happy to recommend the following resources, which are updated regularly:

https://www.cdc.gov/coronavirus/2019-ncov/index.html

https://www.who.int/emergencies/diseases/novel-coronavirus-2019/advice-for-public