With rising questions and several reports of COVID 'reinfections,' a new study claims that immunity to coronavirus might last for a longer period of time than estimated.
Most people who have recovered from the coronavirus still have enough immune cells to fend off the virus, even after months, reports New York Times. This slow decay indicates that cells may survive for a longer period of time inside our bodies, finds the study that has not been peer reviewed yet.
The study's author told NYT,
“That amount of memory would likely prevent the vast majority of people from getting hospitalized disease, severe disease, for many years,”Shane Crotty, study lead, avirologist at the La Jolla Institute of Immunology
This may come as a relief for those who thought vaccines will have to be administered repeatedly to keep the pandemic under control.
The research also solidifies another finding that claims that most SARS-COV-2 survivors carry essential immune cells for a long time. To add to that, another recent study emphasised that COVID-19 survivors build powerful and protective killer immune cells
Not All People Show Immunity
However, a small proportion of people in this study didn't show immunity after recovery. Expert Jennifer Gommerman, an immunologist from the University of Toronto, told NYT that the reason could be the varying degree of coronavirus that people have been exposed to. Gommerman also suggested that this variability can be overcome by vaccines.
Yet the fear of multiple attacks by the virus still remains. Immunologists agree that it is natural for antibody levels to drop. And besides antibodies, even sterilising immunity plays a role in preventing subsequent attacks.
“Sterilising immunity doesn’t happen very often — that is not the norm,”Alessandro Sette, co-study lead, an immunologist at the La Jolla Institute of Immunology
The Study
Dr Sette and his colleagues recruited 185 men and women, aged 19 to 81, who had recovered from COVID-19. Majority had mild symptoms not requiring hospitalisation; most provided just one blood sample, but 38 provided multiple samples over many months.
In the study, four components were observed : antibodies, B cells that make more antibodies as needed; and two types of T cells that kill other infected cells. All the components were essential for the end result.
The study found that B-cells multiplied while T cells only demonstrated a slight decay in the body. Antibodies were durable, however there was a massive difference in the levels among the participants.
Since scientists are yet to figure what levels and proportions of different immune cells are needed to combat the virus, the longevity of the immune cells is still a mystery. But with the new study and the knowledge that even small amounts of T and B cells or antibodies can be enough to protect has brought us closer to solving this mystery.
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