Scientists don’t yet have definitive answers about SARS-CoV-2 immunity. For now, people who have had the disease appear unlikely to get it again, at least within the bounds of the current outbreak. Small, early studies in animals suggest immune molecules may stick around for weeks (at least) after an initial exposure. Because researchers have only known about the virus for a few months, however, they can’t yet confidently forecast how long immune defenses against SARS-CoV-2 will last.
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From the immune system’s perspective, some pathogens are unforgettable. One brush with the viruses that cause chickenpox or polio, for instance, is usually enough to protect a person for life. Other microbes, however, leave less of an impression, and researchers still aren’t entirely sure why. This applies to the four coronaviruses known to cause a subset of common cold cases.
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COVID-19 packs a stronger punch than the common cold, so antibodies capable of fending off this new coronavirus may have a shot at lingering longer. Broadly speaking, the more severe the disease, the more resources the body will dedicate to memorizing that pathogen’s features, and the stronger and longer lasting the immune response will be, says Allison Roder, a virologist at New York University.
