What are “antibodies” anyway?

New on the scene; antibody tests for the coronavirus family of viruses. Just the other day the ever-excitable Governor Cuomo of New York (and to be fair, he’s had plenty to be excited about recently) was talking about rolling out an “aggressive” antibody testing effort there, which would help determine how many people had been exposed, and might be immune, to COVID-19 viruses.

Filtered through the news media, it is not immediately apparent that the Governor is completely clear on what antibodies actually are, which again, to be fair, is not in his job description. But with the media undoubtedly about to pick on this new developing story, perhaps other people will be asking themselves the question:  What are antibodies, exactly, and what do they mean in this situation?

First important piece of information:

ANTIBODIES ARE NOT INFECTIOUS OR CONTAGIOUS AND HAVING THEM DOES NOT NECESSARILY MEAN A PERSON CAN SPREAD A DISEASE.

What antibodies are, are chemical compounds that your body makes in response to detecting foreign material in your body. Antibodies stay mostly in your bloodstream, and do not leave the body. Your body likes to save energy, so if you haven’t been exposed to a certain illness in a while, it often stops making so many antibodies, which is why you have to get “booster shot” vaccines.

In the best-case scenario, these antibodies then help in fighting off the disease that brought that material inside you. They bind to the foreign material, identifying it as bad to your body’s other defensive mechanisms, such as “white blood cells.” Your body then attacks and destroys or neutralizes the invading material.

We don’t always get the best-case scenario, of course.  Sometimes antibodies form to things we really don’t need to fight off, like pollen, or form against the body itself, leading to autoimmune diseases. Sometimes antibodies can be present and ready to help, but really too weak to help stave off a particular infection.

For diseases, the foreign material can get in there in two ways. First is from the big, bad world outside, as “germs,” that get inside your body through your nose, mouth, eyes, ears, skin, rectum, urethra, cuts, sores, and so on. The other way is through vaccination, in which case a substance that is very similar to a disease germ, but lacks its virulence, is deliberated introduced into your body. Your body then forms antibodies that can fight off the actual disease.

What does it mean if a person has antibodies to coronaviruses (either COVID-19 or something considered similar enough to count)?

AGAIN, THIS DOES NOT MEAN THEY NECESSARILY INFECTIOUS. IT ONLY MEANS THEY HAVE BEEN EXPOSED TO THESE VIRUSES AT SOME POINT IN TIME.

Viral illness spread by spreading the actual virus. Now if a person has an active case of a respiratory virus, they may also be forming antibodies at the same time. So, a person could have both virus and antibodies at a certain point in time. If they were at that time continuing to “shed virus” as the medical terminology states it, they could infect another person with the viruses they expel. However, if a person has antibodies, but no symptoms, they are extremely unlikely to be able to spread a respiratory illness, because at that point, they have most likely already finished the active, viral laden part of their illness. If they have antibodies but no virus present they cannot spread an illness.

Have people with coronavirus related antibodies all had a coronavirus related illness? That depends on your definition of coronavirus related illness. They have certainly been exposed to whatever viruses their particular test tests for, because that’s how you get antibodies. Your body can’t make antibodies without something to react against. They may or may not have actually had any symptoms, however.

Are people with antibodies “immune” to COVID-19? That is, if some gets into their bodies, will their immune system quickly and effectively take care of it, so they don’t experience actual illness?

Short answer, nobody knows. Antibodies vary in effectiveness, and they don’t often get produced in high levels indefinitely. Coronaviruses are cold viruses, and everybody knows that you don’t just catch one cold in your lifetime and then call it a day. Part of that is that there are a lot of viruses that cause “colds,” part is that viruses mutate and change over time, and part is that immunity can wear off. On the other hand, some vaccines or diseases give lifelong immunity after you have them once. Again, nobody knows yet what is going on in this particular recent outbreak. So long as antibodies are doing their job correctly, it’s probably better to have an immune response ready for a germ than not.

Why does anyone what to check for these, then? What New York State plans to do is check a sample of about 3,000 hopefully random people, to try and get an idea of how prevalent exposure to COVID-19 might be in the general community. This could be useful in determining how dangerous the virus really is, as when we only know about serious cases, we only see the worst results. It could also be a good guide as to what public health protections might work best. In previous posts, we have discussed that the lack of testing, and testing the wrong people (i.e. people we already know are sick) for coronavirus has been a problem in the United States. Used correctly, information about exposure levels could be helpful. Of course, expect it to be fodder for media scare stories as well. It’s unlikely that these stories will be scientifically based, and more likely they will be “it walks among us, hiding under our beds,” type stories. Don’t get sucked into this.

SUMMARY:

ANTIBODIES ARE NOT INFECTIOUS AND DO NOT SPREAD DISEASE.

ANTIBODIES MAY INDICATE A PERSON IS “IMMUNE” TO A DISEASE, BUT THIS IS NOT A GIVEN.

SCREENING MAY BE HELPFUL TO ANSWER QUESTIONS ABOUT HOW DANGEROUS THIS VIRUS ACTUALLY IS, OR WHAT PUBLIC HEALTH MEASURES MIGHT BE THE MOST HELPFUL, BUT BE ALERT FOR “SCARE STORIES” THAT DON’T REALLY UNDERSTAND WHAT ANTIBODIES ARE OR WHAT THEIR PRESENCE MEANS.