Antibody immunity to coronavirus may be short-lived: UK study

Patients who recover from the novel coronavirus may have an antibody response that makes them immune to the deadly virus only for a few months, a new study in the UK has found.

A paper titled Longitudinal evaluation and decline of antibody responses in SARS-CoV-2 (Covid-19) infection', by King's College London researchers, analysed the immune response of more than 90 patients and healthcare workers at Guy's and St Thomas' NHS Foundation Trust, the London hospital which had treated Prime Minister Boris Johnson after he tested positive for coronavirus in March.

Research, led by Dr Katie Doores of King's College London, found levels of antibodies that can destroy the virus peaked about three weeks after the onset of symptoms then started declining.

People are producing a reasonable antibody response to the virus, but it's waning over a short period of time and depending on how high your peak is, that determines how long the antibodies are staying around, Doores told The Guardian.

Infection tends to give you the best-case scenario for antibody response, so if your infection is giving you antibody levels that wane in two to three months, the vaccine will potentially do the same thing. People may need boosting and one-shot might not be sufficient, she explains.

The study is the first longitudinal research to have monitored antibody levels in patients and hospital workers for three months after symptoms emerged. The scientists drew on test results from 65 patients and six healthcare workers who tested positive for the virus, and a further 31 staff who volunteered to have regular antibody tests between March and June.

Antibody (Ab) responses to SARS-CoV-2 can be detected in most infected individuals 10-15 days following the onset of Covid-19 symptoms. However, due to the recent emergence of this virus in the human population, it is not yet known how long these Ab responses will be maintained or whether they will provide protection from re-infection, notes the paper, which is yet to be peer-reviewed.

The immune system has multiple ways to fight the coronavirus but if antibodies are the main line of defence, the findings suggest people could become reinfected in seasonal waves just like the common cold and other kinds of flu.

"This study has important implications when considering widespread serological testing, Ab protection against reinfection with SARS-CoV-2 and the durability of vaccine protection, the paper adds.