The study, led by scientists at La Jolla Institute for Immunology at San Diego university in the USA, assessed elements of the immune response including antibodies and T-cells, and found the "immune memory" may last for at least eight months. The authors claimed that this is the first study of its kind, incorporating antigen-specific antibody, memory B cell, CD8+ T cell, and CD4+ T cell measurements, out past 6 months post-infection.
The more antibodies people had, the lower their chances of re-infection.
Dr Katie Jeffery, director of Infection Prevention and Control for Oxford University Hospitals said: "This is an exciting finding, indicating that infection with the virus provides at least short-term protection from re-infection - this news comes in the same month as other encouraging news about COVID vaccines".
A new study supports evidence that delirium can predict coronavirus infection in older patients who show no other typical symptoms of Covid-19.
Scientists are developing understanding of the role of T-cells but a recent study found people testing negative for coronavirus antibodies may still have some immunity.
Antibodies build up during a viral infection and stop the virus from getting inside the body's cells and attacking the rest of the immune system.
They found that the TNF-alpha and IFN-gamma combination triggered tissue damage and inflammation that mirror the symptoms of Covid-19 along with rapid death.
Research teams led by Sheahan and co-lead author Michel C. Nussenzweig, who is a professor, investigator, and senior physician at The Rockefeller University and Howard Hughes Medical Institute, tested the ability of several human antibodies to prevent SARS-CoV-2 infection in mice or hamsters.
But none of the three became unwell.
"By studying these multiple compartments of adaptive immunity in an integrated manner, we observed that each component of SARS-CoV-2 immune memory exhibited distinct kinetics", the researchers wrote in the study.
The staff tested were followed for up to 30 weeks.
"We are therefore confident that the majority of people who have survived SARS-CoV-2 infection have some protection against reinfection with SARS-CoV-2", he added. They found 91.1% of those who had recovered from COVID-19 had antibodies against the virus months after infection. The researchers focused on a select set of the most elevated cytokines in COVID-19 patients, the hospital said.
Scientists said the results indicated most people are unlikely to get COVID-19 again if they have already had it in the previous six months.
It is known as the innate immune response and includes the release of chemicals that cause inflammation and white blood cells that can destroy infected cells.