New research, undertaken by the German state of Bavaria, has found that people who have been infected with coronavirus start losing antibodies just a few months after recovering. Essentially, this means that people who have already contracted the virus could do so again.
A research project undertaken the Schwabing Clinic in Munich found that antibodies, which develop while someone is suffering from coronavirus and help neutralise the infection, start to decrease rapidly just months after the infection has been fought off. The project studied patients who have recovered from the virus from January onwards.
“In four out of nine patients, we see falling neutralising antibodies in a very special test that can only be carried out in a high-security laboratory," said Clemens Wendtner, chief physician of the Schwabing Clinic. "The extent to which this has an impact on long-term immunity and vaccination strategies is still speculative but must be monitored critically as it progresses."
The findings have led to doubts regarding the effectiveness of herd immunity, as well as the long-term immunity of those who have already recovered from the virus.
The findings concur with reports of people from South Korea and China contracting coronavirus again, despite having already recovered from it. A similar study from China also found that antibodies decreased significantly two months after patients initially caught the infection. Furthermore, those who were infected but did not develop symptoms accrued fewer antibodies than those who did display symptoms.
The researchers said more work needed to be done to determine the extent to which these declining antibodies could prevent further infection.