New research suggests that protective immunity to SARS-CoV-2 lasts eight months or more

The relationship between immune memory, pictured from Science, 2021, doi:10.1126/science.abf4063.
data show that the immune response is present and remains the same," said Sette.
," Crotty said, "we measured antibodies, memory B cells, auxiliary T cells, and killer T cells at the same time."
to our knowledge, this is the largest study ever conducted to measure all four components of immune memory for any acute infection.
" These findings may mean that COVID-19 survivors may have protective immunity to serious diseases caused by SARS-CoV-2 virus infection within a few months or years of infection with SARS-CoV-2 virus.
new study could help clarify some data from other laboratories on COVID-19, which showed a sharp drop in antibodies resistant to COVID-19 in the months after infection.
that the drop in these antibodies means the body will not be able to fight re-infection.
Sette explains that the drop in antibodies is very normal.
, "Of course, the immune response will decline to some extent over time, but that's normal," Sette said.
is what the immune response does.
immune response rises in the first stage, and after this magical expansion, they eventually contract and reach a stable state.
" the researchers found that virus-specific antibodies do persist in the blood for months after infection.
important, the body also has immune cells called memory B cells on standby.
if a person encounters SARS-CoV-2 again, these memory B cells can be reactivated and produce SARS-CoV-2 antibodies to fight re-infection.
the SARS-CoV-2 virus uses its "spike" protein to initiate infections in human cells, the researchers looked for memory B cells specific to SARS-CoV-2 prickly proteins.
found that after six months of infection, there was actually an increase in prickly protein-specific memory B cells in the blood.
COVID-19 survivors also have an army of T-cells ready to fight re-infection.
memory CD4 plus "assistive" T cells will persist for a long time and can trigger an immune response at any time if they see SARS-CoV-2 again.
many memory CD8 plus "lethal" T cells still exist, ready to destroy infected cells and prevent re-infection.
different parts of the adaptive immune system work together, so it bodes well to see antibodies, memory B cells, memory CD4 plus T cells, and memory CD8 plus T cells in the blood more than 8 months after infection.
means that people are likely to have protective immunity during this time, at least against serious diseases, and probably well beyond that period of time," Crotty said.
"The team cautions that protective immunity does vary from person to person.
, the researchers saw a 100-fold range of immune memory.
with weak immune memory may be vulnerable to a recurrence of COVID-19 in the future, or they may be more susceptible to infection.
, "Some people have poor immune memory, and maybe they're more likely to get infected again," said Crotty, a government source.
," Weiskopf added, "people who appear to have been infected need a degree of protective immunity to prevent re-infection."
how protective it is remains to be determined.
" immune memory of SARS-CoV-2 is possible, which also bodes well for vaccine developers.
Weiskopf stressed that the study tracked responses to natural SARS-CoV-2 infections, rather than immune memory after vaccination.
, "Immune memory may have a similar persistence after vaccination, but we have to wait until the data are available to determine."
our research a few months ago has shown that natural infections induce strong reactions, and now this new study suggests that they are long-lasting.
is still in its infancy and has so far been shown to have a strong protective effect.
hope that vaccine-induced reactions will develop similar patterns over time.
" The researchers will continue to analyze samples of COVID-19 patients over the next few months and hope to track their responses within 12 to 18 months of the onse.
Sette said, "We're also doing very detailed analysis to determine which virus fragments are identified at a higher granular level."
and we plan to evaluate not only the immune response after natural infection, but also the immune response after vaccination.
are also trying to understand how immune memory is different in people of different ages and how this may affect the severity of COVID-19 cases.
: 1.Jennifer M. Dan et al. Immunological memory to SARS-CoV-2 assessed for up to 8 months after infection. Science, 2021, doi:10.1126/science.abf4063. 2.Protective immunity against SARS-CoV-2 could last eight months or more