Professor Ooi Eng Eong, deputy director of the emerging infectious diseases programme at Duke-NUS Medical School, said that antibodies are but one part of the immune response that would protect patients from reinfection.
“Measuring only antibodies thus misses the other half of the immune response – those mediated by killer T-cells,” said Prof Ooi.
“Using antibody levels alone to infer immunity could thus be misleading.”
Both antibodies and T-cells are important elements of the human immune response against viral infections due to their ability to directly target and kill infected cells.
Separately, Singapore scientists found in another study the presence of virus-specific T-cell immunity in people who have recovered from Covid-19 and severe acute respiratory syndrome (Sars), as well as in some healthy study subjects who have never been infected by either virus.