Latest data on immune response to COVID-19 reinforces need for vaccination, says Oxford-led study

Commentary

A health care worker study (PITCH) supported by the UK Coronavirus Immunology Consortium and conducted in collaboration with the universities of Liverpool, Sheffield, Newcastle, and Birmingham, investigated protective immunity from T cells to COVID-19 in 78 health care workers who experienced symptomatic or asymptomatic disease. Nineteen of the workers and an additional eight patients experiencing severe disease were studied.

Blood samples were collected monthly for one to six months after infection to investigate immune responses. The results showed that some people in both the symptomatic and asymptomatic groups had undetectable immune memory 6 months after infection, or even earlier. Thus, there may be a risk that these people will be reinfected.

The researchers were using a new machine learning approach (called SIMON) to identify detailed patterns in the data to see if early disease severity and early immune response could predict long-term immunity. Using this approach, Dr. AdrianaTomic of the Oxford VaccineGroup and the study authors found an early immune signature associated with both cellular and antibody immunity that was detectable as early as one month after infection.

The majority of people with symptomatic disease had measurable immune responses at 6 months post-infection, but a significant minority (17/66; 26%) did not. The majority of people who experienced asymptomatic disease (11/12; 92%) did not have a measurable immune response at 6 months post-infection. This underscores the importance of getting vaccinated, as antibodies may not persist for a long period of time even if there is a history of infection.