viral infection and immunity: the promise of remote sampling

We are living in unprecedented times. In March 2020, the World Health Organization (WHO) upgraded the COVID-19 epidemic to a pandemic and different countries implemented different ways to tackle the spread of the infectious disease known as SARS-CoV-2. Much of this involves social distancing, especially for the vulnerable in our societies.  

The rapid spread of the virus put strains on healthcare systems and the WHO recommended that governments test for the virus as much as they can. 

Current Ways to Test for Viral Infection

There are two primary ways to specifically test for viral infection:

1. Testing for the direct presence of the virus
2. Testing for antibodies raised against the virus.

Direct Viral Testing

Direct viral testing, which has been employed for diagnosis of COVID-19, involves detecting the presence of viral nucleic acids in affected tissues using rapid PCR techniques. Although rapid PCR allows for detection of specified viruses, it says nothing about if an individual has raised any antibodies to the virus. 

Antibody Testing

Screening for raised antibodies, allows for vaccine manufacturers to test the efficacy of their vaccines. This involves employing the use immunoassays specific to the pathogen or pathogens of choice and involves a blood test. However, blood sampling is challenging to accomplish when social distancing measures have been employed and healthcare systems are being stretched. In short, home testing kits that enable people to mail a dried blood sample to a laboratory can potentially help to reduce such a burden.  

Use of Remote Dried Blood Assays in Monitoring of Disease 

The use of remote sampling of dried blood samples for diagnosis of disease is widely used in screening neonates for inborn errors of metabolism. Over the years, there have been many papers published on the use of remote dried blood collection for monitoring viral infections such as HIV and hepatitis.   

In 2019, a paper was published in the Journal of Clinical and Translational Science, where the use of remote Volumetric Absorptive Microsampling was evaluated to successfully measure immunity to 33 stains of influenza virus. The test employed by the research lab was a multidimensional multiplex immunoassay to measure IgG antibodies. Twenty-one healthy volunteers were recruited to evaluate the feasibility of combining the benefits of at-home finger-stick blood sampling, with the mPlex-Flu assay.

In each case, phlebotomists were used to collect both venous blood via a traditional venipuncture blood draw, and capillary blood samples using Mitra devices and a lancet to prick the fingertip. The study volunteers were also asked to self-collect additional blood samples at home using Mitra^® devices based on VAMS^® technology. This enabled them to mail the sampled devices back to the lab.

The results were very impressive, including the following highlights: 

• Very good concordance (R2 0.9470) was observed when comparing the venous serum samples vs. extracts from the dried Mitra samples collected by the phlebotomists; 

• Equally excellent concordance (R2 0.9496) was observed between Mitra samples collected by the phlebotomists and the samples self-collected by volunteers at home;
  
  
• The samples looked very stable and, even more encouraging, this study was conducted in the New York area during an August heatwave where the samples mailed back to the lab would have been exposed to high temperatures.

Can microsampling be used for COVID-19? 

We contacted the lead author on the study (Dr. Jiong Wang) to see if their research group was developing a similar assay for COVID-19. She reported, "We are going to be using the same methods to estimate the antibodies against COVID-19 viral proteins, such as S, N, M, E and multiple strains. That will be helpful for vaccine development and understanding the mechanism of COVID-19 severe illness. We intend to use the Mitra^® Microsample Collection Kits for large scale sampling."

More Microsampling Information 

If you are curious to explore remote microsampling and how volumetric dried blood assays can help track viral infection and immunity, please contact us to speak with one of our expert Microsampling Specialists.