@lnxw48a1 18 months, maybe 12 or less if it gets fast tracked (it most likely will and will be without full knowledge of side effects until maybe 18-24 months from start) and from what I have read the vaccine could only be effective for about a year, they really don't know.

Coronavirus vaccines: five key questions as trials begin
https://www.nature.com/articles/d41586-020-00798-8

>If humans do develop immunity, how long does it last?

>That’s another big unknown. Immunity is short-lived for the coronaviruses that cause common colds; even people who have high levels of antibodies against these viruses can still become infected, says Stanley Perlman, a coronavirologist at the University of Iowa in Iowa City.
>
>The evidence is more equivocal for the two other coronaviruses that have triggered epidemics: those that cause severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS). Perlman says his team has found that after people recover from MERS, their antibodies against the virus drop precipitously. He also says that his team has gathered data — not yet published — showing that SARS antibodies are still present in the body 15 years after infection. But it’s not clear whether this immune response is enough to prevent reinfection. “We don’t have good evidence of long-lasting immunity, but we also don’t have really good data from both SARS and MERS,” Perlman adds.