The refinement may take as long as a week; both the process and the potency of the final antibodies can vary. Some people make powerful neutralizing antibodies to an infection, while others mount a milder response.
The antibodies generated in response to infection with some viruses — polio or measles, for example — bestow a lifetime of immunity. But antibodies to the coronaviruses that cause the common cold persist for just one to three years — and that may be true of their new cousin as well.
A study in macaques infected with the new coronavirus suggested that once infected, the monkeys
produce neutralizing antibodies and resist further infection. But it is unclear how long the monkeys, or people infected with the virus, will remain immune.
Most people who became infected during the SARS epidemic — that virus is a close cousin of the new coronavirus, called SARS-CoV-2 — had long-term immunity lasting eight to 10 years, said Vineet D. Menachery, a virologist at the University of Texas Medical Branch at Galveston.
Those who recovered from MERS, another coronavirus, saw much shorter-term protection, Dr. Menachery said. People who have been infected with the new coronavirus may have immunity lasting at least one to two years, he added: “Beyond that, we can’t predict.”