Study: immunity from SARS-CoV-2 can last for at least six months

Study: immunity from SARS-CoV-2 can last for at least six months, or it may be longer, maybe a matter of years. Researchers also studied different forms of immunity, including antibodies, B cells and two groups of T cells. The study included 185 U.S. adults aged 19 to 81 who had recovered from infection with COVID-19. Researchers: Antibody reaction among the “200-fold set” participants in the study. The findings are consistent with the] latest discovery of SARS T cells 17 years after the original infection,” according to researchers. The findings are consistent with the latest observation that survivors of the SARS epidemic already had T cells more than a decade after recovery, they add. The results were released on Monday in the open-source e-virus journal iReporter on the bioRxiv pre-print server. The research was carried out by scientists at the La Jolla Institute of Immunology in California and the Icahn School of Medicine in New York.
Reference
Coronavirus immunity could last more than 6 months, possibly years: study. https://www.foxnews.com/health/coronavirus-immunity-6-months-possibly-years-study

Resistance to Covid-19 infection remains for at least five months

Resistance to Covid-19 infection remains for at least five months, investigators reported — and probably lengthier than that.

While the study may seem perplexing and contradictory to a comparable report out of Britain this week, it is not. People’s bodies generate an army of immune substances in response to an infection, and many are complicated at first, succumbing off quickly, while others develop more gradually.

The new account out Wednesday reveals 90% of men and women who recover from #Covid-19 infections maintain a stable antibody reaction.

British study demonstrates proof of subsiding immunity to Covid-19.

Although some researchers have suggested antibodies to this virus go away rapidly, experts have found just the reverse — that more than 90% of individuals who were moderately or averagely ill produce an antibody response strong adequate to counteract the virus, and the response is preserved for countless months.
This is important for successful vaccine improvement.

Can one get infected with Covid-19 two times? It is challenging
The team examined the antibody responses of more than 30,000 people who tested positive for Covid-19 at Mount Sinai’s Health System between March and October. They characterized their antibody reactions as minimal, moderate, or high. At least 90% had moderate to high amounts, or titers, of antibodies to the virus’s surge protein — the structure it uses to grip the cells it infects.

They then accurately studied 121 individuals who restored and contributed their plasma — once three months after they first produced signs, and again five months later.
Reference
Immunity to coronavirus lingers for months, study finds. https://www.cnn.com/2020/10/29/health/covid-immunity-lingers-months-wellness/index.html

A sizable English study showed the sheer number of individuals with Covid-19 antibodies declined significantly

A sizable English study showed the sheer number of individuals with Covid-19 antibodies declined significantly throughout the summer, suggesting that having the virus may well not confer long-lasting immunity from future infection.

The survey of 365,000 adults in England who tested themselves in the home using a finger-prick test showed the proportion of men and women testing positive for #Covid-19 antibodies declined by 26.5% between June 20—12 weeks following the peak of infections when looking at the country—and Sept. 28.

The outcome also suggested that folks who did not display symptoms were expected to lose detectable antibodies before they showed symptoms. The analysis, conducted by Imperial College London and Ipsos Mori polling organization, was funded because of the British government, which announced the outcome and published the analysis on Monday night. Other experts have not yet reviewed the outcome.

Doctors do not yet know whether antibodies confer any effective immunity against reinfection by Covid-19. However, just because they are doing, and the link between this survey is confirmed, it suggests the outlook of widespread, long-term herd immunity into the virus should be tough to achieve. Herd immunity occurs when enough people in a population develop an immune response, either through previous infection or vaccination, so the virus cannot spread quickly, and those who are not immune have protection.

The findings showed that 18-24-year-olds lost antibodies at a slower rate than those aged 75 and over. The littlest decline of 14.9% was of men and women aged between 18 and 24 years, together with the largest decline of 29% was of men and women aged 75 and over.

The analysis reflects earlier smaller trials and implies that antibodies into the virus decline over 6-12 months after infection, such as other seasonal coronaviruses, for instance, the common cold. The analysis does not indicate whether other kinds of immune responses—such as that contributed by so-called T cells—would help drive back reinfection.

The analysis showed that 6% of England’s population had antibodies on June 20, compared to 4.4% on Sept. 28. After September, 9% of individuals displayed antibodies in London, compared to just 1.6% in all affected regions when looking at England’s southwest.

Among ethnic groups, 13.8% of Black people tested with antibodies at end-September and 9.7% of Asians—mainly South Asians. This is compared to 3.6% of white people. Minority ethnic groups, when looking at the U.K., such as the U.S., have suffered disproportionately through the virus.
Reference
Study Shows Covid-19 Antibodies Waning Over Time, Suggesting Immunity May Wear Off. https://www.msn.com/en-us/health/medical/study-shows-covid-19-antibodies-waning-over-time-suggesting-immunity-may-wear-off/ar-BB1aqa1Z?li=BBnb7Kz