Fri. Nov 18th, 2022

The results do not suggest people wont get reinfected. Rather, they suggest their immune systems should be able to control that infection and protect them from getting seriously ill.
This study, from The La Jolla Institute for Immunology, significantly expands the findings of an Australian study published in the sister journal, Science Immunology, last month.
“The La Jolla study is beautiful, ” says Associate Professor Menno van Zelm, from Monash Universitys Department of Immunology and Pathology, who lead the Australian research.
“The La Jolla study is beautiful,” says Associate Professor Menno van Zelm. Monash
“They did the same long-term follow up with 188 patients and looked at the whole breath of the adaptive immune response and showed all aspects are quite long lived. We looked at 25 patients and at antibodies and B cells.
“I’m very relieved we came to the same conclusion. The work strengthens each study, has been performed independently and is exactly how science works.”
The La Jolla researchers analysed blood samples from patients mostly from San Diego who had been naturally infected with COVID-19 and had not been vaccinated.
“We measured antibodies, memory B cells, helper T cells and killer T cells all at the same time,” says co-leader of the study, Professor Shane Crotty.
“As far as we know, this is the largest study ever, for any acute infection, that has measured all four of those components of immune memory.”
The immune response usually ramps up after infection and then decreases over time, until it reaches a stable state.
The researchers found virus-specific antibodies persist in the bloodstream months after infection. Importantly the body also has immune cells, called memory B cells, at the ready.
If a person encounters the virus again, these memory B cells could reactivate and produce antibodies to the virus to fight re-infection.
The researchers say different parts of the adaptive immune system work together and seeing all the components in the blood more than eight months following infection is a good sign.
They caution, however, that this protective immunity can vary greatly from person to person, noting they saw a 100-fold range in the magnitude of immune memory.
People with a weak immune memory may be vulnerable to recurrent COVID-19 in the future, or may be more likely to infect others.
That immune memory against the virus is possible, is a good sign for vaccine developers. It indicates at least some of the vaccine should be able to elicit immunity memory. This could be as long lasting after vaccination as it is after natural infection.
The team will continue to analyse samples from these study participants to track their responses 12 to 18 months after the onset of symptoms.