As more people get over COVID-19, they have immunity. Considering there may have been cases in the U.S. since December or January, that means plenty of people now cannot get sick from the virus.

And the best expert estimate right now is that immunity could last up to three years. And it could possibly help others attack this virus.

The good news is testing for antibodies is much easier compared to testing for the virus that causes COVID-19.

In addition to red and white blood cells, the blood has serum. The serum has many proteins doctors can measure for various ailments.

In the case of COVID-19, the infectious disease caused by SARS CO-V-2, when the immune system begins to recognize the viral assailant, it produces two types of antibodies, IGM and IGG.

IGM acts rapidly determining the body’s initial response to infection. But over time IGG intensifies and lasts in the blood indicating a person has recovered from the infection and now has immunity that can be detected and possibly donated through their blood.

The antibodies potentially provide long lasting immunity.

So how do doctors find the antibodies? All it takes is a simple finger prick, much like how diabetics test their blood sugar. Just mail in the sample for evaluation.

Dr Elizabeth McNally said at Northwestern Medicine, they’re working on getting a system in place with the goal of ultimately running hundreds of antibody tests a day.

“Antibodies are proteins that float around in the blood stream. They are reasonably stable. What we’re looking for over the next couple of weeks is having something where we can reach out,” McNally said. “The best would be a mechanism where we could get blood samples from people at home and get them in and be able to get them results about what type of immunity our community has actually experienced. I think that is going to be critically important for us going forward.”

Coronavirus spikes are now an iconic image but they’re more than fascinating art, they’re actually critical to the formation of antibodies.

“When you see all those pictures of the little red spikes sticking out of the virus, that’s the spike protein,” McNally said. “Specifically they are looking at what is called the receptor binding domain – the part of the spike protein that then attaches to cells. That is what people are extremely interested in, looking at antibodies to those regions. That’s actually thought to be indicative of recovery and protection.”

Just as important is making synthetic antibodies in the lab to help those acutely ill with COVID-19.

“If we could come up with an antibody that actually is highly protective, then that could be used for the acutely ill infected person to cut down on their infection and potentially save their life,” McNally said.  “So yes, this isn’t just a signal of who has been infected and who has immunity, but the real homerun is to figure out some antibodies we could use therapeutically.”

There are a number of commercial companies working on antibody tests.

But buyer beware when it comes to home testing kits. McNally said make sure you are dealing with a reputable source. It is best to ask your doctor first or use a test from a known healthcare organization, and even for those with immunity, a vaccine, once it’s developed, will be recommended for protection.