Millions of children missed routine immunizations during pandemic, insurance data shows

Immunity to the coronavirus that causes Covid-19 can last for at least six months, and possibly much longer, if not years, when all components of the body’s immune memory are taken into account, according to early research .

The pre-print document, published Monday on the online server biorxiv.org, appears to contradict previous research which has shown that immunity to the new coronavirus declines over time based on measurements of antibodies or protein components in the system. immune.

Yet the new study – which has not been peer reviewed or published in a scientific journal – involves analyzing several compartments of immune memory over time: antibodies, B cells, and T cells, among other characteristics of the immune system. immune memory.

About the study: The study included 185 adults, aged 19 to 81, in the United States who had recovered from Covid-19. Most of the adults had mild illness.

The researchers – from the La Jolla Institute for Immunology, the University of California at San Diego, and the Icahn School of Medicine at Mount Sinai – analyzed blood samples from adults, collected at various points after the onset of symptoms, some collecting more than six months later.

In the blood samples, the researchers looked at the components of immune memory. They found that the antibodies “were durable” with only “modest declines” emerging at six to eight months, but noted that there was an approximately 200-fold range in the level of antibody responses in adults. .

The researchers also found that memory B cells were detected in almost all cases of Covid-19 and that there appeared to be an increase in memory B cells over time. “B-cell memory of some other infections has been observed to be long lasting, including more than 60 years after vaccination against smallpox, or 90 years after infection with influenza,” the researchers wrote in their report. study.

The researchers identified two types of T cells and their data suggests that “T cell memory may reach a more stable plateau, or a slower decay phase, later than the first 6 months after infection,” they said. they wrote.

Remember: The study has limitations, including the fact that more research is needed to determine whether similar results would emerge in a larger group of people at multiple times.