COVID-19 Immunity Test

Orbis' COVID-19 immunity test quantitatively measures antibodies that bind and neutralize the spike protein, the sticky part of the coronavirus that allows it to enter our cells.


Why test for immunity?

The last two years have shown that this coronavirus isn’t going anywhere soon. So, if it’s inevitable you’re going to meet the virus, then you want to be in the best position that you can when you encounter it.

Immunity is a very good indication of the level of protection a person has against a virus. For many people, knowing how protected they are against severe Covid-19 infection will be really helpful as they figure out what they are comfortable doing in an environment of uncertainty.

Immunity is not an on-off switch, it’s a spectrum that changes over time and varies widely between individuals. We know that breakthrough infection is more likely as time goes on since the last dose of vaccination and antibody levels wane, which is why boosters are so important. But because everyone responds differently to their vaccinations, a blanket approach to the timing of ongoing doses will leave some of us more vulnerable than others.

Everyone will have a different risk appetite which is why having accurate and timely information about your own risk of infection will allow individuals to determine what social activities they consider are safe for them to engage in.

What’s being tested?

Orbis is measuring specific neutralizing antibodies generated against the coronavirus from either vaccination or prior infection.

By measuring these antibody levels, key components of our immune system, research has shown that it is possible to estimate a person’s individual risk of symptomatic infection. Boosters can bring waning antibody levels back up at the time most needed, optimising our population’s protection on an ongoing basis.

What’s the difference between antigen testing and antibody testing?

Antigen testing by PCR is used to determine active infection, while antibody testing determines one’s immune response to the virus or vaccination. As we move through this next phase of the pandemic, understanding one’s own immunity status is important. Orbis’ COVID-19 Immunity test provides an evaluation of the immune response to the virus or vaccine, allowing individuals to know if prior infection or vaccination has resulted in a protective immune response.

I think I’ve had COVID-19. Can this test confirm that?

Orbis is measuring specific neutralizing antibodies generated against the coronavirus from either vaccination or prior infection. Your overall antibody level can be influenced by having had Covid-19 in the past, however the test cannot distinguish between vaccination and prior infection.

Antibodies are just one part of the immune system. What about cellular immunity?

The immune system is complex with many moving parts. Orbis is not measuring the entire immune system, but rather one important component that’s linked with your protection from infection. This is known as humoral (antibody-mediated) immunity.  

Cellular immunity is the other main branch of the immune system, and also plays an important role in the response to Covid-19 and other infectious diseases. For example T cells, which are key for clearing a virus out of infected cells. They are not as specific in their response as antibodies, which makes them more flexible at fighting variants. They can also endure for many months or years following infection or vaccination and can help more antibodies to be produced when needed.

However, T cells are not easy or quick to measure - the latest available tests have at least a seven-to-ten day turnaround time. While it’s possible that you could be protected from Covid-19 by T cells even with a low antibody level, they don’t seem to be as important as antibodies. “The antibody response is the most critical response for protection by vaccination, not the T cell response” concludes the lead author of a recent study that challenged T cell depleted monkeys with the coronavirus.

How are you adapting to new variants?

As the virus continues to evolve, there is the possibility that the antibodies required to neutralize it will also change. For the Omicron variant, the good news is that research shows that booster doses can boost antibody levels high enough to compensate for a lack of a perfect match.

Orbis has adapted its assay to account for protection against the Omicron variant and will notify customers if the test is updated to a new variant of concern.

What’s the benefit of a quantitative antibody test compared to a qualitative antibody test?

Quantitative tests provide a numeric result. In relation to Orbis’ Covid-19 immunity test this measures the concentration of neutralizing antibodies from a finger-prick blood sample. This number can then be converted to determine the protection an individual has against symptomatic infection. On the other hand, qualitative tests provide a binary yes/no result, for example 'yes, antibodies detected' or 'no antibodies detected'. Rapid strip antibody tests are qualitative but are used to diagnose infection rather than immunity as they are limited by their sensitivity. Leading researchers have concluded that only a quantitative immunity test can provide sufficient information to assess the level of protection a person has gained against Covid-19, and monitor this level over time to determine how it is tracking. 

The US FDA announced on 15 November 2021 that, for the first time, it also intends to focus its review on emergency use authorization requests for lab-based and Point of Care high volume antibody tests that can measure the amount of antibodies (fully quantitative antibody tests) or the amount of neutralizing antibodies, which is what Orbis Diagnostics provides.