[EvaH (OP)]

Steve asks:

Care home worker here. I had the virus at least 6 months ago, most staff have antibodies as of 6 weeks ago. Should we be having any of the vaccines? Any research as to what happens to someone who already has the antibodies if they are given a vaccine? If the answer is we should still have one, then which of the front runners should we be having?

Can you help?

[Kryptid]

I would say yes. The antibody count goes down over time. The vaccine should help get the numbers back up again.

[alancalverd]

As to which "front runner" - I'd go for the first to reach me. The probability of reinfection increases every day, so why wait?

[set fair]

The body mounts a different response to a vaccine compared to disease infection. There ought to be a study of how vaccination affects those previously infected with covid. https://www.biorxiv.org/content/10.1101/2020.11.15.383323v1 gives some insight. In the OP's position I would want to be vaccinated... with the half dose Oxford vaccine perhaps.

[evan_au]

The fact that you recovered shows that you did develop an effective immunity at the time.
- But different people develop an immune response to different parts of the virus - whatever your immune system notices first
- Antibodies to some parts of the virus will be more effective than others. What we ideally want are neutralizing antibodies, which bind to the spike protein, and stop it from entering cells, ideally blocking infection before it happens.
- Many of the vaccines are aimed at the spike protein, although it's not clear yet whether they produce neutralizing antibodies.

So a booster shot is probably a good idea.
Oops - overlap with set fair...

[Petrochemicals]

I would say yes. The antibody count goes down over time. The vaccine should help get the numbers back up again.

What effect do antibodies rampaging round your system have, sepsis or fatigue?

[Bored chemist]

What effect do antibodies rampaging round your system have, sepsis or fatigue?

Fairly obviously, neither.
All of us have loads of antibodies in our blood all the time- as a result of having fought off countless infections over our lives.

[annie123]

I have tried to get an answer to this question from every supposed authority/web site/ radio programme/tv programme ad nauseam with no luck. If someone has recovered from covid, had anti bodies, has been free of symptoms for at least 2 weeks, why do they have to quarantine/isolate 2 weeks when visiting another jurisdiction? My Swedish based son cannot come to Canada to see me although he has had all the above. No one will say when he will be acceptable. No one will say whether a vaccinated person has the same conditions, although the suggestion is that once vaccinated everything will be all right again. What is the difference between the two in terms of threat to another population? One person told me that the recovered person could get the disease again which was why they couldn't come, but that will be true of everyone who has had it, so that's the end of the tourist industry. Vaccinated people could also get it again =- a few of them - so will the same apply to them?
I can't see the elites following these rules.Does BJohnson think he can go anywhere now? The media should keep careful watch on who among our 'better/richers' go away fro Xmas and don't isolate, or go anywhere outside their own jurisdictions, and make examples of them until,they come up with rules for the above that make sense for everyone.

[alancalverd]

why do they have to quarantine/isolate 2 weeks when visiting another jurisdiction?

Because (a) the most likely place to acquire an infection is any form of public transport and (b) I know of at least one traveller who lied about his journey, claiming to have spent 2 weeks in an approved travel corridor when he had actually just arrived from an infectious urban jungle and changed planes with a 2-hour break.

[evan_au]

If someone has recovered from covid, had anti bodies

If you depend on people just saying so, that is an unacceptable risk for any country.

Everyone who recovers will develop antibodies to different parts of the virus, and these antibodies will have different effectiveness against future infection.
- You could do an antibody test on arrival in a new country to confirm your claim
- One of the problems with antibody tests is that they may only detect antibodies to a couple of proteins, and so some recovered people will show up as a "negative" for antibodies.
- After a few months, the level of antibodies decline, and you will again show up as "negative" for antibodies
- nobody is yet sure how long the antibodies will be protective.
- The only solution then is to go into quarantine if you fail the antibody test at the airport - an unexpected delay of 2 weeks in a planned 1-2 week vacation!.

In contrast, if we had an internationally-recognized vaccination certificate, stating which vaccine you had received (and when, and where), the current trials will give a good indication of:
- Whether the vaccine protects you from catching the virus (no quarantine) or just protects you from the severe disease (quarantine)
- how long the vaccine is protective
- when you need a booster shot

The reality is: until a significant fraction of the population is fully vaccinated (enough for herd immunity=60% to 80%), the risk of an outbreak is severe.
- So quarantine restrictions will probably remain in place until the end of 2021 in many countries.
- At least for people coming from a country with a higher infection rate (eg Sweden to Canada)
- I'm afraid Zoom or Facetime might have to suffice for your Christmas greetings this year (other software is available)
- You may find that it is easier for you to travel to Sweden - but good luck getting back into Canada! (And take care of yourself while you are in Sweden - you will be more at risk than your son...)