A new study conducted by researchers from Stanford Medicine explored one way to identify the severity of COVID-19 cases. According to their work, analyzing patients’ antibodies shortly after the onset of symptoms may indicate whether their case will be mild or severe.
“We’ve identified an early biomarker of risk for progression to severe symptoms,” said researcher Dr. Taia Wang. “And we found that antibodies elicited by an mRNA vaccine – in this case, Pfizer’s – differ in important, beneficial ways from those in infected people with SARS-CoV-2 who later progress to severe symptoms.”
Antibodies highlight differences in infection severity
For the study, the researchers collected blood samples from nearly 180 adults who tested positive for COVID-19. The team analyzed the participants’ antibodies the day they tested positive and then again 28 days later. When the study began, all of the participants had mild symptoms.
Ultimately, the researchers identified two major differences in antibodies between participants who had mild cases of COVID-19 and those with severe cases. For starters, they explained that neutralizing antibodies are the cells that are most effective at stopping pathogens from inciting more serious infections. Neutralizing antibodies played an important role here, as participants who developed severe cases of COVID-19 started the trial with very low levels of neutralizing antibodies. Conversely, participants with healthy levels of neutralizing antibodies tended to have mild symptoms.
The second difference was in the way that the antibodies were able to create chains that contain sugars that are important for immunity. These sugar fucose cells work with the antibodies to ensure inflammatory levels stay at a healthy place. However, the study showed that patients who went on to develop severe symptoms lacked these fucose cells, and their bodies were producing inflammatory cells at a much faster rate.
“Some inflammation is absolutely necessary to an effective immune response,” Wang said. “But too much can cause trouble, as in the massive inflammation we see in the lungs of people whose immune systems have failed to block SARS-CoV-2 quickly upon getting infected.
Understanding the vaccine response
The researchers also looked at how Pfizer’s COVID-19 vaccine affected participants’ antibody response. They compared the antibody blood samples of 29 adults who had received both doses of the vaccine with participants who developed severe cases of infection and those who had mild cases.
The findings from the first round of testing held up. Participants who were vaccinated showed higher levels of neutralizing antibodies and higher antibody fucose levels, both of which were linked with more mild cases of COVID-19.
The researchers concluded that the makeup of consumers’ antibodies is likely to predict the severity of their COVID-19 infection.