Ideally, if someone gets COVID-19, their body produces antibodies and they become immune from ever getting it again or they get immunity that lasts for several years. The answer to this is still unknown, but it doesn’t appear likely if we judge on the presence of antibodies in patients who have been infected.
A recent Chinese study showed that antibodies produced in response to COVID-19 may not last more than a few months, particularly if the infected patient was asymptomatic.
The study of 37 people with symptoms and 37 people with infection but no symptoms found after two months, 40% of the people without symptoms showed no antibodies while 18% of those who had symptoms with their infection showed no antibodies.
The authors concluded: “Together, these data might indicate the risks of using COVID-19 ‘immunity passports’ and support the prolongation of public health interventions, including social distancing, hygiene, isolation of high-risk groups and widespread testing.”
The study raises into question whether or not herd immunity (where enough of the population has had the disease and remain immune so that disease runs out of hosts to pass the germ onto) can ever be reached.
COVID-19 could well be with us forever (lacking scientific breakthroughs) just like the common cold, although with much more vicious (lethal) symptoms.
As a personal side note. I had an antibody test in early June, four months after my two week illness that left me with lingering shortness of breath. The test showed I had no antibodies, but I guess this study means I still cannot rule COVID out as the cause.