Biology

Your body remembers every infection it beats

The first time your body meets a germ, it takes a week or more to build a weapon that fits it. After winning, it keeps long-lived memory cells tuned to that exact germ, so a second encounter is crushed in hours. Some antibodies last a lifetime: after measles, their half-life is over 200 years.

Sources & further reading

New England Journal of Medicine (Massachusetts Medical Society)Duration of Humoral Immunity to Common Viral and Vaccine AntigensA decades-long study showing antibodies against some viruses, like measles, can last far longer than a human lifetime.Nature Medicine (Nature Publishing Group)Duration of antiviral immunity after smallpox vaccinationA study finding smallpox defences still present in people more than 50 years after a single vaccination.Immunity (Cell Press)T Follicular Helper Cell Biology: A Decade of Discovery and DiseasesA review of how the body refines antibodies and then keeps long-lived memory cells that carry them.Immunity (Cell Press) / PubMed, National Library of Medicine (NIH)Humoral immunity due to long-lived plasma cellsThe study showing antibody-making cells settle in the bone marrow and keep secreting antibody for a very long time.Nature (Nature Publishing Group)Cross-neutralization of SARS-CoV-2 by a human monoclonal SARS-CoV antibodyThe study behind a COVID-19 antibody drug that came from a memory cell made by a SARS survivor back in 2003.Centers for Disease Control and PreventionHow Flu Viruses Can Change: Drift and ShiftThe public-health explanation of why the flu virus keeps changing its surface, so the vaccine is updated every year.World Health OrganizationThe eradication of smallpoxThe WHO record that smallpox was declared eradicated in 1980, the only human disease ever wiped out.