I believe it lasts at least 6 months. Could be much longer. There hasn't really been enough time to confirm yet whether it lasts for a year or more. But people who had the original SARS still have antibodies for it.Pyrrho wrote: ↑Thu Dec 10, 2020 7:52 am Can't find a link--actually can't be arsed to find a link--but IIRC immunity from having had the virus lasts about 6 months.
Length of immunity from the vaccine remains to be seen although the data show that some people in the clinical trials who received the vaccine did get the virus anyway.
There was a study in Japan, and while I cannot seem to find the study itself, here's the Japan TImes' write-up:
Japan study finds 98% of COVID-19 patients had immunity six months later
Personally, I'm betting that if 98% still have antibodies after 6 months, it's a good bet that there will be long-term immunity in a solid majority of people.A Japanese research team has detected antibodies that neutralized the virus that causes COVID-19 in 98% of people who had been sick with the disease in tests performed six months after they became infected.
The team, led by Yokohama City University professor Takeharu Yamanaka, said Wednesday it plans to conduct a follow-up survey to see whether the people will still have such antibodies a year after their infections.
In the latest survey, which was the largest of its type conducted in the country, the team checked blood samples from 376 people who had already recovered from COVID-19. The samples were collected six months after they were infected.
“In general, people with neutralizing antibodies are believed to carry a low risk of reinfection,” Yamanaka told a news conference.
“This gives some hope” in relation to the vaccines set to be released, with the study showing that immunity obtained through natural infection can last at least six months, according to Yamanaka.
He cautioned, however, that immunity acquired through natural infection is not necessarily the same as that obtained from a vaccine.
The study was conducted on individuals who expressed an interest in participating, mostly from Tokyo, Kanagawa and Osaka prefectures. The average age of the participants, with equal numbers of men and women, stood at 49.
Of the participants, 71% had mild symptoms, 19% moderate symptoms and 6% severe symptoms, while 4% showed no symptoms.
The neutralizing antibodies were detected in 97% of the participants who were asymptomatic or had mild symptoms and 100% of those who experienced moderate or severe symptoms. Antibodies tended to be stronger in those whose symptoms had been more severe.
In the study, the team used cells from monkeys genetically modified to easily catch a virus similar to the novel coronavirus. After injecting blood serum taken from the participants into the cells, the team examined whether infection of the cells was prevented.
Various types of antibodies are created inside human bodies in response to viral infections. Some antibodies do not prevent further infection.