Recovered COVID-19 patients may lose their immunity to the virus within months - and could catch it again and again much like a common cold, a UK study suggests.
A team of King's College London scientists have studied the immune response of 90 patients and healthcare workers who had contracted COVID-19. The research found levels of antibodies capable of destroying the SARS-CoV-2 virus peaked about three weeks after the onset of symptoms - but then rapidly declined.
Although 60 percent of people's immune systems demonstrated a strong antibody response at the peak of their infection, just 17 percent retained the same potency three months later.
Over the three-month-period, antibody levels became undetectable in some cases.
"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," Dr Katie Doores, the study's lead author, said in an interview with The Guardian.
The findings suggest people who have recovered from the virus could become reinfected in seasonal waves, particularly if antibodies are the main defence.
The effectiveness of a vaccine has also been called into question.
"If your infection is giving you antibody levels that wane in two to three months, the vaccine will potentially do the same thing," Doores said, suggesting that one shot of a COVID-19 vaccine may not provide sufficient protection.
The research also discovered antibody levels increased - and remained for a longer period - in more severe cases of the virus, potentially due to the patients producing more antibodies to fight a more relentless infection.
Co-author Professor Stuart Neil noted that people are typically susceptible to reinfection from the four other types of common coronavirus, responsible for an average winter cold. He suggested to The Guardian that the SARS-CoV-2 virus may follow the same trend, in terms of protective immunity against it not lasting indefinitely.
The study has been submitted to a journal but is yet to be peer-reviewed.
