The immune response following a coronavirus infection can vary from individual to individual and may not be sufficient to fight against Alpha and Beta variants of Covid-19, according to study reinforcing the need for vaccination .
The study found that people who produced a weak immune response signature, obtained one and six months after infection, had no neutralizing antibodies against the Alpha variant, and none developed a neutralizing antibody response against the Beta variant. .
The preprint study was conducted by the University of Oxford, in collaboration with the universities of Liverpool, Sheffield, Newcastle and Birmingham, suggests that whether it is a symptomatic or asymptomatic infection, it does not protect necessarily long-term people with Covid-19, especially against worrisome new variants.
“Our study is one of the most comprehensive accounts of the immune response to Covid-19 in symptomatic and asymptomatic individuals. It is very important that we all receive the Covid vaccine when it is offered, even if you think you have had Covid-19 before, ”said Christina Dold, from the University of Oxford.
“We found that individuals had very different immune responses from each other after Covid-19, with some people in the symptomatic and asymptomatic groups showing no evidence of immune memory six months after infection or even earlier,” added Dold.
The study looked at how the immune system responds to Covid-19 in 78 healthcare workers who had suffered from symptomatic or asymptomatic illness. Eight other patients with severe disease were included for comparison.
Blood samples were taken monthly 1 to 6 months after infection to examine different parts of the immune response. The report details a very complex and variable immune response following infection with Covid-19.
The team found an early immune signature, detectable one month after infection and linked to both cellular immunity and antibodies, that predicted the strength of the immune response measured six months after infection.
This is the first time that such a signature has been discovered and provides a better understanding of the development of lasting immunity.
While the majority of people with symptomatic disease had measurable immune responses six months after infection, a significant minority (26%) did not. The vast majority of people who suffered from asymptomatic disease (92%) did not show a measurable immune response six months after infection, the researchers said.