A brief report by Ryan T. Demmer et al at the University of Minnesota, Minneapolis published in the February 2022 issue of Mayo Clinic Proceedings reported on a study measuring both raised spike and nucleocapsid protein antibodies from blood microsamples collected remotely using Mitra® devices with VAMS® technology.
The paper is entitled “Identification of Natural SARS-CoV-2 Infection in Seroprevalence Studies Among Vaccinated Populations.” It describes a serological study of 81 healthcare workers (HCWs) before and during a COVID-19 vaccination program.
The study team was able to conclude that raised antibodies to the nucleocapsid protein was an accurate predictor of recent infection among a population of vaccinated HCWs. The team stated that these findings suggest that in the era of COVID-19 and SARS-CoV-2 vaccination, “seroprevalence studies monitoring natural infection will require assays that capture reactivity to the nucleocapsid protein.”
As of the May 2022, there have been more than 6 million deaths worldwide from COVID-19, with approximately 1 million of these in the United States alone. However, an April 2022 study by the Commonwealth Fund stated that COVID-19 vaccinations in the US saved over 2 million American lives, prevented 17 million hospitalizations and 66 million SARS-CoV-2 infections, and also saved $900 billion in associated healthcare costs.
Indeed, at the time of writing, 11.7 billion doses of the vaccines had been administered worldwide. Sadly, the statistics for low-income countries were not as positive, with less than 16% of these populations having received only one dose or more.
With their relatively high vaccination rates, many higher income countries are returning to normal life and beginning to learn to live safely with COVID-19 in their populations. This allows researchers to continue conducting serological and related studies of the virus and its prevalence.
In these studies, it is important to differentiate antibodies raised as a result of vaccination compared to antibodies raised as a result of natural infection. The work outlined by Ryan T. Demmer et al showed that measuring raised antibodies to nucleocapsid antigen, and comparing this to spiked antigen, was a reliable method to distinguish naturally raised antibodies from those raised by vaccination.
The reason for this is that the current SARS-CoV-2 vaccines target the spike protein only, so upon vaccination individuals do not raise antibodies to the nucleocapsid protein, only the spike. In contrast, when individuals are infected by SAR-CoV-2, their immune systems respond by raising antibodies against many of the viral proteins, including spike and nucleocapsid.
The study by Ryan T Demmer et al demonstrated the importance of differentiating vaccination raised antibodies vs natural immunity. As the world continues to open its borders and return to what approximates “normal life” prior to 2020, the likelihood of new SARS-CoV-2 variants being transmitted will potentially increase.
The massive success of the worldwide vaccine program has, to a certain extent, put the brakes on COVID-19 in many countries. Nonetheless, governments should remain vigilant for future waves of infection.
Furthermore, new variants may emerge where current vaccines may be less effective in protecting populations.
Therefore, allowing healthcare professionals to distinguish between natural antibodies vs vaccine-raised antibodies will provide critical serosurveillance as new waves of infection occur.
Indeed, we know from the microsampling work of the US National Institutes of Health (NIH) and others, which was conducted at the beginning of the pandemic, rates of COVID-19 infection were actually a lot higher than had been predicted by antigen testing alone.
The tool developed by Ryan T Demmer et al and others will be critical to obtain accurate population serological data early to allow for early planning to help mitigate further outbreaks.
Furthermore, because samples in this study were remotely collected using Mitra devices with success, it validates how effective home sampling is in contributing to furthering our knowledge of the COVID-19 Pandemic.
This study report was summarized for our readers by James Rudge, PhD, Neoteryx Technical Director. This is curated content. To learn more about the important research outlined in this review, visit the original report published in the Mayo Clinic Proceedings.
Image Credits: iStock, Neoteryx
For more information on microsampling, visit our infectious disease resources.
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