reopening? offer SARS-CoV-2 antibody screening for optimal safety
by Neoteryx | 3 min read
COVID-19 social distancing and face masking restrictions are gradually being lifted globally, but questions remain regarding how to safely return to the workplace.
The COVID-19 vaccines now being administered to the public provide some immunity to the SARS-CoV-2 virus, but this immunity does not last forever. Viral immunity is driven by antibodies that develop in a person’s body to fight a viral invader. When these antibodies begin to disappear over time, that person again becomes susceptible to infection from the virus and its variants.
To minimize the risk to their employees’ health, many companies have chosen to implement routine blood test screening for COVID-19 antibodies among their in-house staff, even for those that received both doses of an approved vaccine. If these screenings can detect specific neutralizing antibodies that are known to block SARS-CoV-2, they could provide an easy way to minimize the spread of the virus and newer variants.
Identifying SARS-CoV-2 Antibodies
The presence of SARS-CoV-2 antibodies within a person’s body indicates the person has developed a resistance to infection by this novel coronavirus. The antibody proteins bind to any SARS-CoV-2 cells around them to neutralize their effect, protecting that person from becoming sick or, at the very least, reducing the severity of an infection.
Current research suggests that the IgG class of neutralizing antibodies is the class primarily responsible for fighting SARS-CoV-2. Of these, IgG1 and IgG3 appear to be the longest-lasting and are, therefore, the ones that vaccination and antibody screening efforts are typically focused on.
According to recent research studies, these neutralizing antibodies provide some degree of immunity to SARS-CoV-2 for approximately 8 months after a COVID-19 infection or after receiving a COVID-19 vaccine. The effectiveness of these antibodies wanes over time, and it is believed that they may eventually disappear from the body altogether.
The antibodies raised in the body in response to a COVID-19 illness or a COVID-19 vaccine are expected to confer immunity for approximately the same amount of time, although this is still under investigation. Experts have suggested the virus may not spread widely if 70% of the population develops antibodies against SARS-CoV-2 through vaccination or a previous COVID-19 infection. When this 70% threshold is reached, it will be much safer for people to gather in groups without risk of contracting a serious case of COVID-19 illness. Governments and health officials are doing everything they can in countries around the world to reach that 70% threshold in order to revitalize economies and enable people to move about more freely and without fear.
Why Use Antibody Screening?
Analyzing the blood for the presence of SARS-CoV-2 antibodies offers an accurate way for institutions to screen for COVID-19 immunity. In some cases, blood analysis is even being used to screen for active COVID-19 infection, as an alternative to nasopharyngeal swab testing. Current indications suggest the sensitivity of nasopharyngeal testing is approximately 70%; it misses nearly 30% of positive cases. Further, nasopharyngeal testing can only uncover the SARS-CoV-2 virus if it is present in the person’s nasal cavity on the day the test is taken.
The pitfalls of nasopharyngeal testing have already begun to complicate matters for employers using this method to screen employees upon workplace re-entry. Army recruits reporting for training at Fort Benning, Georgia were recently swab tested for active COVID-19 upon arrival. Four recruits whose tests were positive were immediately isolated from the rest of the group.
However, after approximately three weeks had passed, other recruits began to feel ill. Following another round of swab testing, nearly a quarter of the recruits tested positive for COVID-19. This suggests that at least one infected individual was missed by the initial nasopharyngeal swab screening.
This begs the question, if blood sampling had been used in place of nasopharyngeal swabbing to screen for COVID-19, could this outbreak have been avoided? More studies of results from both types of samples are needed to make this determination.
Blood sampling via a finger-prick method for such screenings is also considered more convenient than nasal swabbing. If finger-prick sampling uses microsampling devices and techniques, the sample collection process can be completed at home or onsite within minutes and with minimal pain. For remote sampling, Mitra® devices can be shipped to recruits or employees in Mitra® Collection Kits. These kits contain easy-to-follow instructions and all supplies needed. The devices in the kits allow any individual to collect high-quality blood samples that can be shipped via regular mail to a centralized location for testing. No professional medical services are needed at any point during the sample collection process. These kit mailings can also provide employees a list of re-entry protocol expectations.
Employees or recruits that haven't developed antibodies may be asked to stay home while the employer determines next steps. Health officials in local governments in many counties or regions are establishing guidelines for employers to follow regarding screening employees and protocols to follow when employees haven't been vaccinated and/or haven't developed antibodies. These protocols aim to keep everyone safe from infection and help contain the spread of the virus in the workplace.