Is it worth annoying my doc by requesting Covid antibody titer?
December 8, 2021 10:20 PM   Subscribe

I am due for bloodwork on Monday, routine stuff. I have had my two vax shots and should get my booster now (prior two were Pfizer). I have MS, diabetes type II, a boatload of autoimmune diseases -- I had a heart attack and triple bypass surgery followed by DVTs in both legs and multiple pulmonary embolisms.

A friend who was also vax'd was surprised to find that she had ZERO antibodies when her doc tested before her booster. She took a different vax for her booster.

My PCP has only known me a year and doesn't seem to like me to ask for extraordinary things. Is a titre test out of the ordinary, or could I ask her to include this, considering how much I have going on? I guess I'd like to know if the vaccination worked for me/stood up to time, given my immune system and co-morbid issues.

Or does this really not matter in the scheme of things? Just get the booster?
posted by alwayson_slightlyoff to Health & Fitness (15 answers total) 1 user marked this as a favorite
Best answer: "Present data are insufficient to determine an antibody titer threshold that indicates when an individual is protected from SARS-CoV-2 infection. There is neither any FDA-authorized or FDA-approved test nor any other scientifically validated strategy that providers or the public can use to reliably determine whether a person is protected from infection." Source

It is fair to want to know the information you're looking for. However, there is no reliable way to do so. So, yes, "just get the booster".
posted by saeculorum at 10:31 PM on December 8, 2021 [21 favorites]

yep, I'm immunosuppressed and my guidance from my infectious diseases doctor is precisely what saeculorum says above.
posted by mochapickle at 10:41 PM on December 8, 2021 [2 favorites]

I would consider, instead of getting a booster you would qualify for a third primary shot and then see if you can get Moderna instead of a Pfizer. (Usually all three would be the same but now that they allow mix and match boosters it might be possible.) With Pfizer the third shot and booster shot are the same. With Moderna, the initial two shots had a much higher level of active material while the booster has a half dose making it comparable to Pfizer. Moderna has had much better active levels as time goes by compared to Pfizer - my nonscientist brain assumes this is because they started with a higher dose so it wears off more slowly over time. So getting a third dose of Moderna might give you more protection then a booster dose of Pfizer. Plus which ever dose you get, getting the third shot now will allow you to get a booster dose in six months and keep your system as primed as possible giving your autoimmune issues.
posted by metahawk at 10:45 PM on December 8, 2021 [8 favorites]

There are studies that show mix-n-match shots generate stronger antibody responses.

But there is no specific level of antibodies that indicates immunity is "on". There are too many variables, like genetic susceptibility to COVID, pre-existing conditions, specific variants of COVID and mixes thereof...

I am not sure having the titre test done would give you more unease or actually ease your concerns either way.
posted by kschang at 12:26 AM on December 9, 2021 [3 favorites]

Antibody titers are "easy" to measure so you can get this done. Antibodies are produced by B-lymphocytes and after vaccination these will hang out ready to go if present with a whiff of The 'Rona. Your T-cells will be spoiling for a fight as well. Measuring these cells is not routine. So antibody titers are a bit like looking for your car-keys under the street-light.
posted by BobTheScientist at 1:08 AM on December 9, 2021 [3 favorites]

Best answer: I pressured my doc for an antibody test last May. At that time, the medical establishment was just beginning to notice the crowd of immune suppressed patients who could not trust that the Vax was effective for them. There are a variety of tests, and there may be some connection between the kind of vax you got and the test you should get.

Looking at your question from the patient point of view, there is every reason to want to know if you have reasonable protection or not. The usual advice to keep up all precautions whether vaxxed or not sounds good, but after two years, the burdens are tiresome, and it would be nice to know if running into a store to buy milk really is a life/death decision. For folks like you and me, the real value of the Vax is not the 75% protection from getting sick, but the huge reduction in the chances of serious disease, hospitalization or death.

OTOH, the test may not answer the question. The test I was given was called "SARS-CoV-2 IgG Ab Nucleocap Interp". Although under the covers, a numeric value is obtained, all that is returned to the patient is whether that value is greater than some threshold level which was set without a lot of scientific basis. The result I got read, in its entirety, "negative ". Objectively reasonable, psychologically unsatisfactory.
posted by SemiSalt at 4:59 AM on December 9, 2021 [2 favorites]

FDA Authorizes New Long-Acting Monoclonal Antibodies for Pre-exposure Prevention of COVID-19 in Certain Individuals
The product is only authorized for those individuals who are not currently infected with the SARS-CoV-2 virus and who have not recently been exposed to an individual infected with SARS-CoV-2. The authorization also requires that individuals either have:
  • moderate to severely compromised immune systems due to a medical condition or due to taking immunosuppressive medications or treatments and may not mount an adequate immune response to COVID-19 vaccination (examples of such medical conditions or treatments can be found in the fact sheet for health care providers) or;
  • a history of severe adverse reactions to a COVID-19 vaccine and/or component(s) of those vaccines, therefore vaccination with an available COVID-19 vaccine, according to the approved or authorized schedule, is not recommended.
posted by 1970s Antihero at 7:15 AM on December 9, 2021 [1 favorite]

So, an anecdote for you:

I got COVID (pretty mild case) in October 2020. At that point they were still asking folks to donate convalescent plasma and I was eager to contribute so I checked my antibody titers... not a trace. I almost thought my PCR test must have been a false positive. Except we had a few folks sick at the same time at work (in my hospital unit).

Then I got vaxxed, twice. Re-checked my titers. Still negative.

Got a booster in August or September (can't remember now but basically as soon as we were eligible).

Needed to get bloodwork for work and paid to recheck my titers on a whim and BAM a gigantic titer.

Got Pfizer all three times.

I have to say, it just gave me a huge psychological boost. I'm still keeping the same precautions but I'm definitely less worried.

So, my advice would be to get the booster first since it's a good idea to get one anyway. And then maybe ask for one for peace of mind.
posted by M. at 8:30 AM on December 9, 2021

Best answer: I do not believe you need to bug your doctor if you are willing to pay a bit more. You can self-refer and sign up at LabCorp or Quest Diagnostics yourself, or there may be other options local to you. Locally here, for example, the University of Minnesota will also do antibody testing for a fee. Make sure it's the semi-quantitative test so that your result includes a level you can track over time (The first test I took just showed presence/absence of antibodies).

But also, yes, just get the booster. The original two doses were probably too close together and the third dose or boost is showing remarkable protection.
posted by mcgsa at 9:52 AM on December 9, 2021

There is an issue with the AstraZenaca antibodies that Antihero posted about. During the trial, there were, proportionally speaking, more cardiac events in the test group than in the control. Reading between the lines, I think the feeling is that it's just a statistical thing, but my guess is that the OP's cardiologist will want to wait until they have more experience.

This affects me too, and it's very disappointing since it may mean a several month delay before getting some sort of anti-Covid protection.
posted by SemiSalt at 10:32 AM on December 9, 2021

Best answer: Primary care doc here--
When we order tests, one of the things we need to think about is whether or how that information will make an impact what we recommend doing. Otherwise the test is essentially wasted money. (this applies to tests across the board, not just COVID-related things)

In your case, we have the following issues:
- you are eligible for, and planning to get, the booster either way
- you have compelling medical reasons to get a booster either way
- as saeculorum notes, we do not currently have much information on whether there is a quantitative antibody threshold that indicates that a person is likely to avoid infection or to have a mild case if infected.

So right now it seems like there' s not a lot of point in checking your titers, because the result wouldn't give you reliable information on your level of immunity and you have strong reasons to just get the booster and no real inclination not to. The end result of checking vs not checking is likely to be receipt of a booster either way.

I have one patient who had COVID in fall 2020 and refuses to get vaccinated but is willing to get titers every 3 months and when they fall below the detection level they will think about getting vaccinated. I have explained to them multiple times that this plan is shaky on both scientific and public health grounds and that I think the most likely result is that they will get COVID again, but they are pretty adamant. I have agreed to keep testing, since I think it's realistically the only way they'll ever agree to a vaccine, although I suspect that once their titers are negative they'll find some other reason not to get it.
posted by The Elusive Architeuthis at 1:44 PM on December 9, 2021 [10 favorites]

Best answer: First and foremost: it is always OK to ask questions of your healthcare provider, even if it annoys them.

In addition to everything saeculorum said above, all of which is the correct answer to the practical matter of your question, it's worth noting that there are different kinds of antibody tests: very broadly, some test for antibodies against the viral nucleocapsid protein (anti-N), and some for antibodies against the viral spike protein (anti-S). All vaccines in the US produce only anti-S antibodies.

Anti-N tests are the most common, have been around the longest, and are what people are usually talking about when they talk about antibody tests. (SemiSalt, it sure sounds like you got this one). They will be positive only in people who have been infected with the SARS-CoV-2 virus[1]. If you've never had covid--even if you're vaccinated and boosted and your immune system is pumping out anti-S antibodies like a champ--your anti-N antibody test will be negative. Because....

Anti-S tests are newer and less common. They can be positive after vaccination and/or after previous infection. This is the test everyone wants to get to "prove" that they're protected by the vaccine, which I desperately wish were possible but simply isn't. Like folks said above, no one really knows what a positive test means in practice.

Here's a paragraph from the CDC that I had to read three times carefully to make sure I understood, taken from a longer and even more complicated document about guidelines for antibody testing:
Current vaccines distributed in the United States induce antibodies to S protein. Thus, the presence of antibodies to N protein indicates previous infection regardless of a person’s vaccination status, while presence of antibodies to S protein indicates either previous infection or vaccination. The presence of antibodies to S protein and absence of antibodies to N protein in the same specimen indicates vaccination in a person never infected or could signal prior infection in a person whose antibodies to N protein have waned.
Tl;dr: get boosted, ask your doctor about the new monoclonals that got an EUA yesterday, wear a well-fitting mask, avoid large indoor gatherings, and hang in there.

[1] Please note that it will not always be positive in everyone who's had covid before, or could be positive once and then negative later, for lots of reasons that can be best summarized as "the immune system is an immensely complicated thing."
posted by jesourie at 3:39 PM on December 9, 2021 [1 favorite]

My husband has MS and take biologics which are immune suppressing. He had an antibody test a few weeks after his Pfizer booster. (First two shots were AZ.) I think the plan was if no antibodies, to try Moderna for a fourth shot. As it turned out, he did have antibodies - but as others have noted above it’s a positive/negative result with no indication of how many. For him it was worth doing for peace of mind and also so if the result was negative he could plan accordingly. His neurologist organised the test.
posted by t0astie at 4:31 PM on December 9, 2021

Response by poster: As usual you folks are amazing and so genuinely kind in sharing your wisdom, knowledge and personal experience. So this is not the hill to die on with my PCP - we are already wrangling on thyroid management.

I have never taken any DMDs for MS or my other autoimmune conditions. Occasional topical steroid use. My providers have told me, for 40 years, never to take vaccines for any purpose -- no flu vaccine, shingles, etc., -- because it would up-regulate my immune system and likely cause an exacerbation. This time around, all bets were off, and I was told: take the vaccine. I hesitated, then acquiesced.

I am more concerned about being over-vax'd than under which most of you will see as folly -- but I guess I fear slipping into further disability more than I fear death.

However it doesn't appear likely that I will gain a definitive answer from the tests available. So I will get the booster -- my cardiologist advised I do so -- and continue best practices.

All my best wishes to you gracious travelers who provided me with the resources and comments above. Be well.
posted by alwayson_slightlyoff at 5:11 PM on December 9, 2021 [2 favorites]

Response by poster: BTW every answer here could and should be marked as "best" -- I just did not want to leave a dizzying wall of green text.
posted by alwayson_slightlyoff at 5:18 PM on December 9, 2021 [1 favorite]

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