#MSCOVID19: antibody positive

Would knowing that you were anti-SARS-CoV-2 antibody-positive change your behaviour? 

The WHO and other public health agencies are trying to play down the importance of having antibodies to SARS-CoV-2 saying they don’t yet have the data to say these antibodies protect you from reinfection. Yes and no. No in that we don’t have data yet in relation to SARS-CoV-2, but YES in relation to other viral infections. 

If you have been infected with SARS-CoV-2, either asymptomatically or symptomatically (COVID-19), and have developed an antibody response (IgM and/or IgG) to the viral proteins then you are likely to be protected from reinfection in the short (months) and intermediated (years) term. We know from other coronavirus infections that these antibody levels wane with time and the protection is lost, which is why we can get repeated infections with other common coronaviruses. I suspect the same may happen with SARS-CoV-2 as well; in other words, immunity may not be life long. 

It is also clear that people who have asymptomatic and mild infections have lower antibody levels than people with severe infections and hence their immunity may be less effective and less longlasting. It also seems that having antibodies to other coronaviruses, i.e. previous coronavirus infections, may protect from getting severe COVID-19. The latter implies that some of these antibodies may be cross-protective. 

A lot of effort is going into the testing of convalescent plasma from COVID-19 patients, which contains anti-SARS-CoV-2 antibodies, as a treatment in severe COVID-19. The preliminary results are looking promising. In addition, many academic laboratories and pharma companies are trying to develop commercial neutralizing monoclonal anti-SARS-CoV-2 antibodies as a treatment to prevent and treat COVID-19. 

All of this evidence, and basic immunology, suggests that having anti-SARS-CoV-2 antibodies is likely to indicate that you will be immune to reinfection in the short to intermediate-term and even if you were reinfected you would get an asymptomatic or mild infection. The whole premise of herd immunity is built on these assumptions, which is why the WHO and public health officials should get off the fence. 

But why are they sitting on the fence? I suspect it has to do with behavioural psychology. They don’t want to see antibody-positive people relaxing their guard and acting normally, i.e. no social distancing, no handwashing, no masks, etc. They would set a bad example for people who are antibody negative. 

But knowing what I know about virology and immunology if I was antibody-positive it would be a great relief to me and my family. I would be at low risk of getting COVID-19, I could see patients face-2-face without putting them at risk and I could reassure my family that I am not going to infect them. I could even potentially visit and help vulnerable people living near me without fear of infecting them. It is for these reasons that I had my blood taken yesterday to find out if I have had SARS-CoV-2 infection or COVID-19. If antibody-positive then that severe flu-like illness I had over Christmas could have been the sentinel event. There is increasing evidence that SARS-CoV-2 was already circulating in London in December and I was unwell for 3 weeks with many symptoms compatible with COVID-19. If it was that event I could have been infected by patients or staff whilst working on the general medical wards. If on the other hand, if I was antibody negative then I will remain super vigilant and may not cancel my life insurance policy just yet.

Long et al. Antibody responses to SARS-CoV-2 in patients with COVID-19. Nature Medicine (2020), Published: 29 April 2020.

We report acute antibody responses to SARS-CoV-2 in 285 patients with COVID-19. Within 19 days after symptom onset, 100% of patients tested positive for antiviral immunoglobulin-G (IgG). Seroconversion for IgG and IgM occurred simultaneously or sequentially. Both IgG and IgM titers plateaued within 6 days after seroconversion. Serological testing may be helpful for the diagnosis of suspected patients with negative RT–PCR results and for the identification of asymptomatic infections.

CoI: none

22 thoughts on “#MSCOVID19: antibody positive”

  1. I work for the NHS and we have all been offered the antibody test. I’ve been more or less shielding since March as on ocrelizumab and received the shielding letter from my neurologist.
    I’ve had no obvious coronavirus symptoms but am considering a test as I’m curious in case I had an asymptomatic case previously.

    My question is around the ocrelizumab. Is it more likely that even if I had COVID 19 that I wouldn’t make detectable antibodies?

    1. Re: “My question is around the ocrelizumab. Is it more likely that even if I had COVID 19 that I wouldn’t make detectable antibodies?”

      That is the million or possibly billion-dollar question. I have been asking Roche to part-fund a study to answer this question, but they are playing ostrich at the moment. We won’t have to wait long to get an answer I am sure the MS community will answer this regardless of Roche trying to answer it themselves.

      My prediction is that ocrelizumab-treated patients will have a blunted antibody response, some negatives, but in general low-titre and poor quality antibodies, i.e. less likely to be neutralizing. You can see why Roche and I suspect Novartis, with ofatumumab in the wings, don’t want to know the answer to this research proposal as it may drive a rapid switch away from anti-CD20 therapies to other DMTs. This may happen anyway as a lot of neurologists are beginning to prepare their patients for a vaccine.

      1. The data will surface, I have seen enough info already to get a feel for what is happening, as these are obvious questions and as antibody tests come online the truth will be out. However the antibody tests will not give the definative answer because the Roche and Abbot tests look for nucleocapsid anti-bodies this is an protein internal to the virus and looks like the best target for showing you are infected however it is not going to tell you if neutralizing antibodies are made. Neutralizing antibodies are what will help prevent re-infection. This needs a test against the Spike protein and in particular the receptor binding domain but the commercial tests typically is against the whole spike.

      2. I would add one thing here and that is if the COVID-19 becomes endemic then it may be differnt to the SARS virus which seems to have died out. If there is no virus to stimulate the immune system, the antibodies eventually go. However, if you keep seeing the virus it will boost the response over and over again and keep the antibody levels up as long as that viral strain that you repsond to is around.

  2. I’ve had my antibodies tested this morning… pending results. I’ll let the ms registry know if there is facility on the questionnaire for that.

    Thoughts are similar to you, I would feel much more comfortable attending a family garden gathering with my parents who are in there 50/60s if I knew I was less likely to be harbouring it. I would keep all other behaviours the same.

    1. Did you feel you have had COVID symptoms? It seems that most tests can spot this in 90-95% or greater….however what will sort the different tests out are the asymptomatic people who have been infected. They often have low borderline levels of antibody. If the test does not have a high detection level you get a false negative.

      1. As many as 40% of those testing positive seem to be asymptomatic according to reports I’ve seen, which is going to make the test and trace strategy pretty difficult as with numbers like this being asymptomatic, we’re going to have to test the entire population. Mind you, the strategy appears to have always been herd immunity by stealth.

      2. You seriously believe the Government in Westminster has any sort of real strategy? Looks more like chicken with head cut off fire fighting to me.

      3. I didn’t have COVID symptoms, although had a worsening of MS symptoms whilst my other half simultaneously had COVID symptoms. I am not really confident, that either he or I have had it but having spent all of lockdown in a hospital so my risk is higher than most.

        The blood was donated for research purposes but results are being given as a sweetener for participation. The study is looking mainly at antibody response in non-symptomatic HCWs, and they are running a spectrum of antibody tests so the results should be more sensitive and descriptive than the standard NHS ones.

        Im yet to make up my mind on the NHS one, can’t figure out whether the government agenda is a PR stunt or just an attempt to consider the outcomes of all the terrible PPE.

  3. My behaviour has already changed, since I realised it’s hardly killing fit/healthy people under 50.
    Everyone should read the ONS (Office for national statistics) reports on death rates, specifically the bit relating to deaths by age group. then you can make a more informed decision regarding yourself and your loved ones.

    I think the reason you give above about behavioural changes is why these numbers aren’t more widely reported.

    If you can prove the data in the link below is false, I’ll happily review my position.


    I’m still following the government guidelines, and I avoid old people as they are the most at risk. I am far less concerned for myself, as for my age group I’m 3 times more likely to die in a fatal car accident, than from Covid 19.

    If you think it’s too dangerous to use a car, that’s a decision for the individual, not government (although driving a car is heavily regulated. Test, speed limits etc).

    I don’t drive due to MS, so another risk factor removed.

    Arm yourself with the facts and you can keep everyone you interact with safer.

  4. Very interesting. Good that you got it so quickly!

    I’m intrigued to hear you say it was probably around earlier. I had symptoms for 10 days in early March when there was no testing. No fever but cough++

    Sadly I’m on ocrelizumab so even if I can get a test (which I’m trying to) I doubt it would show positive anyway. Which may affect whether I can return f2f as a HCP or not. I am desperate to stop working from home!!!

    1. RE: “Sadly I’m on ocrelizumab so even if I can get a test (which I’m trying to) I doubt it would show positive anyway.”

      Not necessarily correct. Anti-CD20 therapies don’t necessarily suppress antibody responses completely, they are more likely to blunt them. So I suggest you get tested and cross the bridge later.

  5. I had a positive antibody test a few weeks ago and it has put my mind and my family’s at rest.
    I received my first dose of Ocrevus in October 2019 and was convinced if I got Covid, it wouldn’t be a great outcome.
    I spent most of January in bed, which I thought was due to sinus and ear infections, exaggerated by MS and Ocrevus. I didn’t know at the time, that Covid was circulating in the UK.
    My positive antibody test has put my mind at rest…..I had Covid and didn’t end up in hospital.
    My first full dose of Ocrevus was due in April and was put on hold due to the risks of the virus. I have a pending date for July and I wont be as scared about receiving it now.
    I hope my story helps.
    Best wishes.

  6. If I tested positive for antibodies then I would give my friends who have had the virus a hug. I’d probably keep all other behaviour the same. My family live in New Zealand, I visited in February so I am unlikely to go back soon. I live alone. And I’m a bit of a stickler for the rules.

    1. If they have had the virus, it will be soon long gone and they wont be infective

  7. We all could benefit from knowing our status. Also if a person had a case with few or no symptoms, why would getting exposed again be worse? Do they have a quality that helps them fight off this virus, even after their immunity-antibodies had dropped? Great article. And comments from people’s experiences more informative than news Blah-Blah. 👍🏼😎

  8. I had a five week cough in March, and was recently offered the test by my neurologist through a teaching hospital in the US. I was sad to see it was negative, but I like to think I would not have changed my behavior, at least not socially. While we don’t know for certain if exposure confers immunity or for how long, every person wearing masks in public and taking pains to not touch their faces and keeping distant from others encourages others to do the same. I’d probably relax my guard more in smaller private social settings, however. I now have a “normal” immune system after a second round of alemtuzumab in May 2019, so the aggressive handwashing bit is second nature anyhow.

  9. Hi Prof G

    My very good friend and her husband, who sadly has PD – had the similar virus to yourself over Christmas. They had both been immunised with the flu vaccine but both had this awful bug that was really awful and gave them both chesty breathing difficulties too!

    If this could have been COVID-19 – then it would come as great comfort to know that they are have the antibodies and can move a bit more freely with their young adult family and social group.

    I’m looking forward to hearing your results.


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