Antibodies to COVID-19 may disappear in some patients in as little as 2 months, according to a new study. As ABC News reported, the findings may dash hopes that so-called "immunity passports" could allow individuals to travel freely.
Antibodies are proteins produced by the body's immune system as protection against pathogens such as viruses or bacteria. When a person is sickened by a virus -- or administered an inactive or weakened pathogen via a vaccine -- the body produces antibodies, which can then fight off the pathogen should it re-infect the patient later.
However, a team of researchers from Chongqing Medical University in China has found that -- in the case of COVID-19, the respiratory illness caused by the novel coronavirus -- it appears that in some patients, those antibodies can fade away in as little as two months. In effect, that means that a patient who gets sick with COVID-19 and then recovers can get sick from it again, rather than being immune from it for the rest of their life.
In the study, researchers compared the immune responses of 37 people who had been diagnosed with COVID-19 but had no symptoms, to 37 patients who had the disease and were showing symptoms. Among the patients who weren't sick, 40 percent had no antibodies in their system just 2 months after they were diagnosed. By comparison, among the sickened patients, just 13 percent had lost their antibodies in the same time frame.
The study's findings seem to back up what the medical community has suspected for some time: that being exposed to the coronavirus once, and even coming down with COVID-19, doesn't necessarily mean that the patient can't get it again.
Dr. Anthony Fauci, the nation's top infectious-disease specialist, said previously that data seems to indicate that antibodies to the coronavirus family of viruses can fade in as little as 3-6 months.
"When you look at the history of the common coronaviruses that cause the common cold, the reports in the literature are that the durability of immunity that's protective ranges from 3 to 6 months to almost always less than a year."
The study's findings also seem to deal another blow to the concept of so-called "immunity passports" -- which is to say, a sort of theoretical documentation that a person has developed immunity to COVID-19 and thus can travel freely or return to work.
However, the Chinese study was small and limited in scope, and the scientific community is far from fully understanding the long-term effects on the body's response to the pathogen.