The change in literature I've observed during the covid-19 pandemic is certainly prompting this question, but I think the question can be answered broadly in terms of immunology, which does have decade after decade of study, rather than the currently unfolding event.

Here's the claim from various sources, yes they're all about covid, I've yet to read the claim for another disease... but plenty more around covid still, if these aren't enough



Some other 'health' website

These all state you should be vaccinated regardless of previous infection.

To be clear, I'm not asking if it's better to get the vaccine or to get infected, obviously avoiding a potentially fatal, easy to spread disease is the better option - but if you've already been infected and recovered, I've always read that the naturally occurring immunity far exceeds that of immunity gained from a vaccine.

In the case of measles it's well documented the vaccine immunity is sub par to survivors - it was still a huge boon to society, created enough immunity to eliminate the disease in our country (yay vaccines!) until the anti-vax movement led to a critical number of parents deciding not to vaccinate their kids and allowing a recurrence (boo anti-vax).

Again looking at measles, amongst numerous other diseases we vaccinate for, it's well documented that contracting and recovering from the disease provides life long immunity. This article does outline an improperly vaccinated population that could catch it, but also supports the life long immunity claim in recovered patients.

I've only ever read this generally, haven't found good primary sources, and assume it will vary by disease to some extent? But really have no idea, please help out with any evidence.

So is there any evidence that shows a vaccine will provide additional protection against an infection the body already has a natural immunity to?

EDIT: I'm not looking for an expert opinion, strictly hard evidence that shows this. I can find plenty of videos of Fauci saying how important it is. Just haven't seen anything that actually backs it up.

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    To be honest it depends on the disease if catching it provides future immunity or not.
    – Joe W
    May 14, 2021 at 0:37
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    If you don't get satisfaction here, this might be a suitable question for Medical Sciences. Although it might fit as-written, it's best to take their tour, study their help center etc.. as you already patently know. May 14, 2021 at 1:48
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    Just to be clear, are you asking if vaccines in general protect someone who had a certain disease, or are you asking only about covid-19 vaccines? If you're asking about all vaccines, then you'll need to find someone specifically making that claim about vaccines in general, or your question may be closed as off-topic for lacking a notable claim.
    – Giter
    May 14, 2021 at 2:53
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    I closed for the reasons commented above. It isn't a notable claim that ALL vaccines give additional protection against reinfection to their corresponding diseases. The question is thus too broad.
    – Oddthinking
    May 14, 2021 at 14:35
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    Side point: IN an areas where there is likely many different studies with many different results, it is quite reasonable to quote experts who provide references to support their views. Discarding all expert sources isn't a fair restriction.
    – Oddthinking
    May 14, 2021 at 14:37

1 Answer 1


Your question cannot be answered broadly. Different viruses are different challenges - the flu, for example, isn't magic, it's just evolved to be incredibly fast at changing (the flu virus genome is in a bunch of tiny pieces that let it quickly swap out parts to find combinations that the population is naive to). HIV is an entirely different challenge for your immune system to respond to.

For COVID-19, there is evidence that the vaccine boosts the immune response to people who have recovered from COVID-19 infection.


In contrast, all SARS-CoV-2 recovered individuals had detectable levels of anti-spike and anti-RBD IgG at baseline, and these antibody responses were significantly increased after the first dose of vaccine (Fig. 1B). However, in SARS-CoV-2 recovered subjects, there was no additional increase in antibody levels following the second vaccine dose (Fig. 1B). Notably, the levels of anti-RBD IgG were similar in the SARS-CoV-2 naïve and SARS-CoV-2 recovered individuals at 1 week post-boost (timepoint 4) (Fig. 1B).

This is additional protection. Immune response varies widely individual to individual after recovery, but is enhanced by vaccination in all individuals in the small cohort tested.

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    It is your personal (&premature) inference to state "this is additional protection" (citation needed). If this Ab goes from already 100 to beyond the theoretical 100%, then what use would the extra 10 in 110 be; there is also 'too much'? Plus: Ab response is not all there is and we also have some evidence pointing at lowered T-cell effectiveness for 'recovered but jabbed again' (which certainly is diminished protection!) 10.1101/2021.02.01.21250923; 10.1101/2021.02.07.21251311; 10.1126/science.abh1282 May 15, 2021 at 12:23

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